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1. Correlated pion-proton pair emission off hot and dense QCD matter

Author

J. Adamczewski-Musch, O. Arnold, C. Behnke, A. Belounnas, A. Belyaev, J.C. Berger-Chen, A. Blanco, C. Blume, M. Böhmer, P. Bordalo, S. Chernenko, L. Chlad, I. Ciepał, C. Deveaux, J. Dreyer, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Fonte, C. Franco, J. Friese, I. Fröhlich, T. Galatyuk, J.A. Garzón, R. Gernhäuser, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Höhne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kämpfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, M. Kohls, B.W. Kolb, G. Korcyl, G. Kornakov, F. Kornas, R. Kotte, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Malige, A. Mangiarotti, J. Markert, T. Matulewicz, S. Maurus, V. Metag, J. Michel, D.M. Mihaylov, S. Morozov, C. Müntz, R. Münzer, L. Naumann, K. Nowakowski, Y. Parpottas, V. Pechenov, O. Pechenova, O. Petukhov, K. Piasecki, J. Pietraszko, W. Przygoda, K. Pysz, S. Ramos, B. Ramstein, N. Rathod, A. Reshetin, P. Rodriguez-Ramos, P. Rosier, A. Rost, A. Sadovsky, P. Salabura, T. Scheib, H. Schuldes, E. Schwab, F. Scozzi, F. Seck, P. Sellheim, I. Selyuzhenkov, J. Siebenson, L. Silva, U. Singh, J. Smyrski, Yu.G. Sobolev, S. Spataro, S. Spies, H. Ströbele, J. Stroth, C. Sturm, O. Svoboda, M. Szala, P. Tlusty, M. Traxler, H. Tsertos, E. Usenko, V. Wagner, C. Wendisch, M.G. Wiebusch, J. Wirth, D. Wójcik, Y. Zanevsky, and P. Zumbruch

Subjects
Baryonic resonances, Heavy-ion reactions, Freezeout, Physics, QC1-999
Abstract

In this letter we report the first multi-differential measurement of correlated pion-proton pairs from 2 billion Au+Au collisions at sNN=2.42 GeV collected with HADES. In this energy regime the population of Δ(1232) resonances plays an important role in the way energy is distributed between intrinsic excitation energy and kinetic energy of the hadrons in the fireball. The triple differential d3N/dMπ±pdpTdy distributions of correlated π±p pairs have been determined by subtracting the πp combinatorial background using an iterative method. The invariant-mass distributions in the Δ(1232) mass region show strong deviations from a Breit-Wigner function with vacuum width and mass. The yield of correlated pion-proton pairs exhibits a complex isospin, rapidity and transverse-momentum dependence. In the invariant mass range 1.1

Published
2021
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2. Identical pion intensity interferometry in central Au+Au collisions at 1.23A GeV

Author

J. Adamczewski-Musch, O. Arnold, C. Behnke, A. Belounnas, A. Belyaev, J.C. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Böhmer, P. Bordalo, S. Chernenko, L. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Fonte, C. Franco, J. Friese, I. Fröhlich, T. Galatyuk, J.A. Garzón, R. Gernhäuser, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Höhne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kämpfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, B.W. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, T. Matulewicz, S. Maurus, V. Metag, J. Michel, D.M. Mihaylov, S. Morozov, C. Müntz, R. Münzer, L. Naumann, K. Nowakowski, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, O. Petukhov, K. Piasecki, J. Pietraszko, W. Przygoda, S. Ramos, B. Ramstein, A. Reshetin, P. Rodriguez-Ramos, P. Rosier, A. Rost, A. Sadovsky, P. Salabura, T. Scheib, H. Schuldes, E. Schwab, F. Scozzi, F. Seck, P. Sellheim, I. Selyuzhenkov, J. Siebenson, L. Silva, Yu.G. Sobolev, S. Spataro, S. Spies, H. Ströbele, J. Stroth, P. Strzempek, C. Sturm, O. Svoboda, M. Szala, P. Tlusty, M. Traxler, H. Tsertos, E. Usenko, V. Wagner, C. Wendisch, M.G. Wiebusch, J. Wirth, D. Wójcik, Y. Zanevsky, and P. Zumbruch

Subjects
Physics, QC1-999
Abstract

We investigate identical pion HBT intensity interferometry in central Au+Au collisions at 1.23A GeV. High-statistics π−π− and π+π+ data are measured with HADES at SIS18/GSI. The radius parameters, derived from the correlation function depending on relative momenta in the longitudinally comoving system and parametrized as three-dimensional Gaussian distribution, are studied as function of transverse momentum. A substantial charge-sign difference of the source radii is found, particularly pronounced at low transverse momentum. The extracted source parameters agree well with a smooth extrapolation of the center-of-mass energy dependence established at higher energies, extending the corresponding excitation functions down towards a very low energy.

Published
2019
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3. Sub-threshold production of Ks0 mesons and Λ hyperons in Au+Au collisions at sNN=2.4 GeV

Author

J. Adamczewski-Musch, O. Arnold, C. Behnke, A. Belounnas, A. Belyaev, J.C. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Böhmer, P. Bordalo, S. Chernenko, L. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Fonte, C. Franco, J. Friese, I. Fröhlich, T. Galatyuk, J.A. Garzón, R. Gernhäuser, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Höhne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kämpfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, B.W. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, S. Maurus, V. Metag, J. Michel, D.M. Mihaylov, S. Morozov, C. Müntz, R. Münzer, L. Naumann, K. Nowakowski, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, O. Petukhov, J. Pietraszko, W. Przygoda, S. Ramos, B. Ramstein, A. Reshetin, P. Rodriguez-Ramos, P. Rosier, A. Rost, A. Sadovsky, P. Salabura, T. Scheib, H. Schuldes, E. Schwab, F. Scozzi, F. Seck, P. Sellheim, I. Selyuzhenkov, J. Siebenson, L. Silva, Yu.G. Sobolev, S. Spataro, S. Spies, H. Ströbele, J. Stroth, P. Strzempek, C. Sturm, O. Svoboda, M. Szala, P. Tlusty, M. Traxler, H. Tsertos, E. Usenko, V. Wagner, C. Wendisch, M.G. Wiebusch, J. Wirth, Y. Zanevsky, P. Zumbruch, and Y. Leifels

Subjects
Physics, QC1-999
Abstract

We present first data on sub-threshold production of Ks0 mesons and Λ hyperons in Au+Au collisions at sNN=2.4 GeV. We observe an universal 〈Apart〉 scaling of hadrons containing strangeness, independent of their corresponding production thresholds. Comparing the yields, their 〈Apart〉 scaling, and the shapes of the rapidity and the pt spectra to state-of-the-art transport model (UrQMD, HSD, IQMD) predictions, we find that none of them can simultaneously describe these observables with reasonable χ2 values.

Published
2019
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4. Transverse extension of partons in the proton probed in the sea-quark range by measuring the DVCS cross section

Author

R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, E. Burtin, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, M. Dziewiecki, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, K. Juraskova, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, I.I. Kuznetsov, A. Kveton, A.A. Lednev, E.A. Levchenko, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, M. Pešková, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, N.S. Rogacheva, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, M. Tasevsky, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, B.M. Veit, J. Veloso, A. Vidon, M. Virius, S. Wallner, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, and M. Ziembicki

Subjects
Physics, QC1-999
Abstract

We report on the first measurement of exclusive single-photon muoproduction on the proton by COMPASS using 160GeV/c polarised μ+ and μ− beams of the CERN SPS impinging on a liquid hydrogen target. We determine the dependence of the average of the measured μ+ and μ− cross sections for deeply virtual Compton scattering on the squared four-momentum transfer t from the initial to the final proton. The slope B of the t-dependence is fitted with a single exponential function, which yields B=(4.3±0.6stat|sys−0.3+0.1)(GeV/c)−2. This result can be converted into a transverse extension of partons in the proton, 〈r⊥2〉=(0.58±0.04stat|sys−0.02+0.01±0.04model)fm. For this measurement, the average virtuality of the photon mediating the interaction is 〈Q2〉=1.8(GeV/c)2 and the average value of the Bjorken variable is 〈xBj〉=0.056. Keywords: Quantum chromodynamics, Deep inelastic scattering, Exclusive reactions, Deeply virtual Compton scattering, Generalized Parton Distributions, Proton size, COMPASS

Published
2019
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5. Longitudinal double-spin asymmetry A1p and spin-dependent structure function g1p of the proton at small values of x and Q2

Author

M. Aghasyan, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, L. Capozza, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, M. Dziewiecki, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, I.I. Kuznetsov, A. Kveton, A.A. Lednev, E.A. Levchenko, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, M. Pešková, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, N.S. Rogacheva, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, M. Tasevsky, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, J. Veloso, A. Vidon, M. Virius, S. Wallner, T. Weisrock, M. Wilfert, R. Windmolders, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, and M. Ziembicki

Subjects
Physics, QC1-999
Abstract

We present a precise measurement of the proton longitudinal double-spin asymmetry A1p and the proton spin-dependent structure function g1p at photon virtualities 0.006(GeV/c)2

Published
2018
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6. New analysis of ηπ tensor resonances measured at the COMPASS experiment

Author

A. Jackura, C. Fernández-Ramírez, M. Mikhasenko, A. Pilloni, V. Mathieu, J. Nys, V. Pauk, A.P. Szczepaniak, G. Fox, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, M. Dziewiecki, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, I.I. Kuznetsov, A. Kveton, A.A. Lednev, E.A. Levchenko, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, M. Pešková, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, N.S. Rogacheva, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, T. Schlüter, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, M. Tasevsky, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, J. Veloso, A. Vidon, M. Virius, S. Wallner, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, and M. Ziembicki

Subjects
Physics, QC1-999
Abstract

We present a new amplitude analysis of the ηπ D-wave in the reaction π−p→ηπ−p measured by COMPASS. Employing an analytical model based on the principles of the relativistic S-matrix, we find two resonances that can be identified with the a2(1320) and the excited a2′(1700), and perform a comprehensive analysis of their pole positions. For the mass and width of the a2 we find M=(1307±1±6) MeV and Γ=(112±1±8) MeV, and for the excited state a2′ we obtain M=(1720±10±60) MeV and Γ=(280±10±70) MeV, respectively.

Published
2018
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7. Deep sub-threshold ϕ production in Au+Au collisions

Author

J. Adamczewski-Musch, O. Arnold, C. Behnke, A. Belounnas, A. Belyaev, J.C. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Böhmer, P. Bordalo, S. Chernenko, L. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Fonte, C. Franco, J. Friese, I. Fröhlich, T. Galatyuk, J.A. Garzón, R. Gernhäuser, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Höhne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kämpfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, B.W. Kolb, G. Korcyl, G. Kornakov, R. Kotte, W. Kühn, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, S. Maurus, V. Metag, J. Michel, D.M. Mihaylov, S. Morozov, C. Müntz, R. Münzer, L. Naumann, K.N. Nowakowski, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, O. Petukhov, J. Pietraszko, W. Przygoda, S. Ramos, B. Ramstein, A. Reshetin, P. Rodriguez-Ramos, P. Rosier, A. Rost, A. Sadovsky, P. Salabura, T. Scheib, H. Schuldes, E. Schwab, F. Scozzi, F. Seck, P. Sellheim, J. Siebenson, L. Silva, Yu.G. Sobolev, S. Spataro, H. Ströbele, J. Stroth, P. Strzempek, C. Sturm, O. Svoboda, M. Szala, P. Tlusty, M. Traxler, H. Tsertos, E. Usenko, V. Wagner, C. Wendisch, M.G. Wiebusch, J. Wirth, Y. Zanevsky, and P. Zumbruch

Subjects
Physics, QC1-999
Abstract

We present data on charged kaons (K±) and ϕ mesons in Au(1.23A GeV)+Au collisions. It is the first simultaneous measurement of K− and ϕ mesons in central heavy-ion collisions below a kinetic beam energy of 10A GeV. The ϕ/K− multiplicity ratio is found to be surprisingly high with a value of 0.52±0.16 and shows no dependence on the centrality of the collision. Consequently, the different slopes of the K+ and K− transverse-mass spectra can be explained solely by feed-down, which substantially softens the spectra of K− mesons. Hence, in contrast to the commonly adapted argumentation in literature, the different slopes do not necessarily imply diverging freeze-out temperatures of K+ and K− mesons caused by different couplings to baryons.

Published
2018
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8. Sivers asymmetry extracted in SIDIS at the hard scales of the Drell–Yan process at COMPASS

Author

C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink

Subjects
SIDIS, Drell–Yan, Spin, Azimuthal asymmetries, Sivers, TMDs, Physics, QC1-999
Abstract

Eight proton transverse-spin-dependent azimuthal asymmetries are extracted in four regions of the photon virtuality Q2 from the COMPASS 2010 semi-inclusive hadron measurements in deep inelastic muon–nucleon scattering. These Q2 regions correspond to the four regions of the di-muon mass Q2 used in the ongoing analyses of the COMPASS Drell–Yan measurements, which allows for a future direct comparison of the nucleon transverse-momentum-dependent parton distribution functions extracted from these two alternative measurements. In addition, for the azimuthal asymmetries induced by the Sivers transverse-momentum-dependent parton distribution function various two-dimensional kinematic dependences are presented. The integrated Sivers asymmetries are found to be positive with an accuracy that appears to be sufficient to test the sign change of the Sivers function predicted by Quantum Chromodynamics.

Published
2017
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9. Multiplicities of charged kaons from deep-inelastic muon scattering off an isoscalar target

Author

C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, L. Capozza, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, F. Sozzi, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, R. Windmolders, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink

Subjects
Deep inelastic scattering, Kaon multiplicities, Quark fragmentation functions, Strange quark, Physics, QC1-999
Abstract

Precise measurements of charged-kaon multiplicities in deep inelastic scattering were performed. The results are presented in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y, and the fraction z of the virtual-photon energy carried by the produced hadron. The data were obtained by the COMPASS Collaboration by scattering 160 GeV muons off an isoscalar 6LiD target. They cover the kinematic domain 1(GeV/c)25 GeV/c2 in the invariant mass of the hadronic system. The results from the sum of the z-integrated K+ and K− multiplicities at high x point to a value of the non-strange quark fragmentation function larger than obtained by the earlier DSS fit.

Published
2017
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10. Interplay among transversity induced asymmetries in hadron leptoproduction

Author

C. Adolph, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, E. Burtin, W.-C. Chang, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, N. d'Hose, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, V. Duic, M. Dziewiecki, A. Efremov, C. Elia, P.D. Eversheim, W. Eyrich, A. Ferrero, M. Finger, M. Finger Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, D. von Harrach, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, N. Horikawa, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, P. Jörg, R. Joosten, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, N. Kuchinski, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, C. Marchand, B. Marianski, A. Martin, J. Marzec, J. Matousek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, Y. Miyachi, P. Montuenga, A. Nagaytsev, F. Nerling, D. Neyret, V.I. Nikolaenko, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, G. Pesaro, M. Pesek, D.V. Peshekhonov, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rychter, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, A. Selyunin, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, F. Sozzi, A. Srnka, M. Stolarski, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, J. ter Wolbeek, S. Tessaro, F. Tessarotto, F. Thibaud, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, T. Weisrock, M. Wilfert, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink

Subjects
Physics, QC1-999
Abstract

In the fragmentation of a transversely polarized quark several left–right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as the Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows quantitative relationships to be established among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.

Published
2016
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11. Search for exclusive photoproduction of Zc±(3900) at COMPASS

Author

C. Adolph, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Austregesilo, B. Badełek, F. Balestra, J. Barth, G. Baum, R. Beck, Y. Bedfer, A. Berlin, J. Bernhard, K. Bicker, E.R. Bielert, J. Bieling, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, E. Burtin, L. Capozza, M. Chiosso, S.U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, C. Elia, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, A. Filin, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, R. Geyer, I. Gnesi, B. Gobbo, S. Goertz, M. Gorzellik, S. Grabmüller, A. Grasso, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. von Harrach, D. Hahne, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, Ch. Höppner, N. Horikawa, N. d'Hose, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, P. Jasinski, P. Jörg, R. Joosten, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, M. Krämer, Z.V. Kroumchtein, N. Kuchinski, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, A. Maggiora, A. Magnon, N. Makke, G.K. Mallot, C. Marchand, A. Martin, J. Marzec, J. Matousek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, Y. Miyachi, A. Nagaytsev, T. Nagel, F. Nerling, S. Neubert, D. Neyret, V.I. Nikolaenko, J. Novy, W.-D. Nowak, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, R. Panknin, D. Panzieri, B. Parsamyan, S. Paul, D.V. Peshekhonov, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, E. Rocco, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rychter, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, C. Schill, T. Schlüter, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, M. Schott, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, S. Sosio, F. Sozzi, A. Srnka, L. Steiger, M. Stolarski, M. Sulc, R. Sulej, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, J. ter Wolbeek, S. Tessaro, F. Tessarotto, F. Thibaud, S. Uhl, I. Uman, M. Virius, L. Wang, T. Weisrock, M. Wilfert, R. Windmolders, H. Wollny, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink

Subjects
Physics, QC1-999
Abstract

A search for the exclusive production of the Zc±(3900) hadron by virtual photons has been performed in the channel Zc±(3900)→J/ψπ±. The data cover the range from 7 GeV to 19 GeV in the centre-of-mass energy of the photon–nucleon system. The full set of the COMPASS data set collected with a muon beam between 2002 and 2011 has been used. An upper limit for the ratio BR(Zc±(3900)→J/ψπ±)×σγN→Zc±(3900)N/σγN→J/ψN of 3.7×10−3 has been established at the confidence level of 90%. Keywords: COMPASS, Zc(3900), Photoproduction, Tetraquark

Published
2015
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12. Odd and even partial waves of ηπ− and η′π− in π−p→η(′)π−p at 191 GeV/c

Author

C. Adolph, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Austregesilo, B. Badełek, F. Balestra, J. Barth, G. Baum, R. Beck, Y. Bedfer, A. Berlin, J. Bernhard, K. Bicker, E.R. Bielert, J. Bieling, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, E. Burtin, L. Capozza, M. Chiosso, S.U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, C. Elia, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, R. Geyer, I. Gnesi, B. Gobbo, S. Goertz, M. Gorzellik, S. Grabmüller, A. Grasso, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. von Harrach, D. Hahne, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, Ch. Höppner, N. Horikawa, N. d'Hose, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, P. Jasinski, P. Jörg, R. Joosten, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, M. Krämer, Z.V. Kroumchtein, N. Kuchinski, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, A. Maggiora, A. Magnon, N. Makke, G.K. Mallot, C. Marchand, A. Martin, J. Marzec, J. Matousek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, Y. Miyachi, A. Nagaytsev, T. Nagel, F. Nerling, S. Neubert, D. Neyret, J. Novy, W.-D. Nowak, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, R. Panknin, D. Panzieri, B. Parsamyan, S. Paul, D.V. Peshekhonov, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, E. Rocco, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rychter, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, C. Schill, T. Schlüter, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, M. Schott, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, S. Sosio, F. Sozzi, A. Srnka, L. Steiger, M. Stolarski, M. Sulc, R. Sulej, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, J. ter Wolbeek, S. Tessaro, F. Tessarotto, F. Thibaud, S. Uhl, I. Uman, M. Virius, L. Wang, T. Weisrock, M. Wilfert, R. Windmolders, H. Wollny, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink

Subjects
Physics, QC1-999
Abstract

Exclusive production of ηπ− and η′π− has been studied with a 191 GeV/c π− beam impinging on a hydrogen target at COMPASS (CERN). Partial-wave analyses reveal different odd/even angular momentum (L) characteristics in the inspected invariant mass range up to 3 GeV/c2. A striking similarity between the two systems is observed for the L=2,4,6 intensities (scaled by kinematical factors) and the relative phases. The known resonances a2(1320) and a4(2040) are in line with this similarity. In contrast, a strong enhancement of η′π− over ηπ− is found for the L=1,3,5 waves, which carry non-qq¯ quantum numbers. The L=1 intensity peaks at 1.7 GeV/c2 in η′π− and at 1.4 GeV/c2 in ηπ−, the corresponding phase motions with respect to L=2 are different.

Published
2015
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13. A high-statistics measurement of transverse spin effects in dihadron production from muon–proton semi-inclusive deep-inelastic scattering

Author

C. Adolph, R. Akhunzyanov, M.G. Alekseev, Yu. Alexandrov, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Austregesilo, B. Badełek, F. Balestra, J. Barth, G. Baum, R. Beck, Y. Bedfer, A. Berlin, J. Bernhard, R. Bertini, K. Bicker, J. Bieling, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bravar, A. Bressan, M. Büchele, E. Burtin, L. Capozza, M. Chiosso, S.U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, C. Elia, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, A. Filin, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, R. Garfagnini, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, R. Geyer, M. Giorgi, I. Gnesi, B. Gobbo, S. Goertz, M. Gorzellik, S. Grabmüller, A. Grasso, B. Grube, A. Guskov, T. Guthörl, F. Haas, D. von Harrach, D. Hahne, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, Ch. Höppner, N. Horikawa, N. d'Hose, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, P. Jasinski, P. Joerg, R. Joosten, E. Kabuß, D. Kang, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, Z. Kral, M. Krämer, Z.V. Kroumchtein, N. Kuchinski, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, S. Levorato, J. Lichtenstadt, A. Maggiora, A. Magnon, N. Makke, G.K. Mallot, C. Marchand, A. Martin, J. Marzec, J. Matousek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, Y. Miyachi, A. Nagaytsev, T. Nagel, F. Nerling, S. Neubert, D. Neyret, V.I. Nikolaenko, J. Novy, W.-D. Nowak, A.S. Nunes, I. Orlov, A.G. Olshevsky, M. Ostrick, R. Panknin, D. Panzieri, B. Parsamyan, S. Paul, M. Pesek, D. Peshekhonov, G. Piragino, S. Platchkov, J. Pochodzalla, J. Polak, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, G. Reicherz, E. Rocco, V. Rodionov, E. Rondio, A. Rychter, N.S. Rossiyskaya, D.I. Ryabchikov, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, C. Schill, T. Schlüter, A. Schmidt, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, M. Schott, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, S. Sosio, F. Sozzi, A. Srnka, L. Steiger, M. Stolarski, M. Sulc, R. Sulej, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, J. ter Wolbeek, S. Tessaro, F. Tessarotto, F. Thibaud, S. Uhl, I. Uman, M. Vandenbroucke, M. Virius, J. Vondra, L. Wang, T. Weisrock, M. Wilfert, R. Windmolders, W. Wiślicki, H. Wollny, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, and M. Ziembicki

Subjects
Physics, QC1-999
Abstract

A measurement of the azimuthal asymmetry in dihadron production in deep-inelastic scattering of muons on transversely polarised proton (NH3) targets is presented. They provide independent access to the transversity distribution functions through the measurement of the Collins asymmetry in single hadron production. The data were taken in the year 2010 with the COMPASS spectrometer using a 160 GeV/c muon beam of the CERN SPS, increasing by a factor of about four the overall statistics with respect to the previously published data taken in the year 2007. The measured sizeable asymmetry is in good agreement with the published data. An approximate equality of the Collins asymmetry and the dihadron asymmetry is observed, suggesting a common physical mechanism in the underlying fragmentation.

Published
2014
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14. Corrigendum to 'Odd and even partial waves of ηπ− and η′π− in π−p → η(′)π−p at 191 GeV/c' [Phys. Lett. B 740 (2015) 303–311]

Author

S. Takekawa, L. Steiger, E. M. Kabuß, R. Panknin, I.A. Savin, N.S. Rossiyskaya, A. Srnka, A. Grasso, Frank Klein, Yu. Kisselev, M. Ostrick, E.R. Bielert, M. Boer, S. Ramos, M. Wilfert, S.-U. Chung, F. Tessarotto, J. Pretz, S.S. Dasgupta, S. Neubert, V. Anosov, S. Gerassimov, D.V. Peshekhonov, C. Quintans, N. Horikawa, M. Büchele, P. Sznajder, H. Wollny, P. Jörg, M. V. Zavertyaev, François Herrmann, Yu. Ivanshin, O.Yu. Shevchenko, S. Levorato, C. Braun, Z.V. Kroumchtein, B. Badelek, M. Stolarski, J.H. Koivuniemi, T. Iwata, M. Krämer, T. Szameitat, Asher Berlin, Fabrice Gautheron, S. Tessaro, D. Hahne, C. Marchand, D.I. Ryabchikov, M. A. Faessler, M. Gorzellik, Ch. Höppner, T. Nagel, A. Lehmann, C. Regali, O. Kouznetsov, K. Königsmann, Miroslav Sulc, R. Joosten, F. Hinterberger, B. Ketzer, R. Sulej, Yu.A. Khokhlov, J. Novy, A. Rychter, M. Chiosso, Franco Bradamante, F. Haas, O.P. Gavrichtchouk, I. Gnesi, Martin Bodlak, R. Hashimoto, R.P. Kurjata, M. Slunecka, R. Akhunzyanov, Y. Miyachi, L. Sinha, K. Klimaszewski, T. Matsuda, R. Geyer, M. Ziembicki, M. Finger, S. Sarkar, Laura Silva, A. Maggiora, A. Zink, I. Konorov, B. Gobbo, G. D. Alexeev, Aram Kotzinian, W. Dünnweber, V.N. Kolosov, K. Schönning, A.A. Lednev, K. Kurek, W. Meyer, Maria Liz Crespo, Lei Wang, M. Virius, T. Michigami, V. Jary, F. H. Heinsius, Federica Sozzi, S. Schopferer, R. Windmolders, Andres Cicuttin, I. Orlov, V.D. Samoylenko, G. Reicherz, L. Capozza, K. Kondo, S. Goertz, P. Schiavon, Mikhail Mikhasenko, S. Grabmüller, K. Bicker, A.B. Ivanov, S. V. Donskov, A. Magnon, Y. Bedfer, S. Sosio, O.Yu. Denisov, F. Kunne, R. Jahn, S. Dalla Torre, V. Duic, A. Sandacz, Alessandro Bressan, D. von Harrach, A. Austregesilo, C. Elia, G.V. Khaustov, G. Baum, G.V. Meshcheryakov, A.S. Nunes, Bakur Parsamyan, P.D. Eversheim, W. Eyrich, P. Jasinski, D. Panzieri, Janusz Marzec, M.G. Alexeev, S. Uhl, R. Beck, B. Grube, H. Suzuki, Nour Makke, J. Bieling, H. Matsuda, T. Grussenmeyer, M. Quaresma, Michal Dziewiecki, S. Platchkov, Yu. V. Mikhailov, Christian Schill, J. ter Wolbeek, C. Franco, J. Pochodzalla, Jan Matousek, S. Sirtl, A.G. Olshevsky, Andrea Ferrero, F. Nerling, Q. Curiel, R. Birsa, J. Lichtenstadt, M. Levillain, D. Neyret, W.-D. Nowak, H. Schmieden, P. Bordalo, F. Thibaud, J. Barth, V. Frolov, Soumen Paul, J.M. Friedrich, N. Kuchinski, J. Bisplinghoff, Gerhard K. Mallot, K. Schmidt, Norihiro Doshita, S. Huber, Matthias Schott, Anne-Laure Martin, T. Weisrock, N. d'Hose, E. Zemlyanichkina, E. Burtin, V.F. Konstantinov, S. Ishimoto, H. Fischer, V. Andrieux, Adam Szabelski, A. Nagaytsev, F. Balestra, K. Zaremba, V.A. Polyakov, G. Sbrizzai, A. Amoroso, N. du Fresne von Hohenesche, T. Schlüter, E. Rocco, C. Adolph, Johannes Bernhard, A.V. Efremov, A. Guskov, and I. Uman

Subjects
Physics, Nuclear and High Energy Physics, Angular distribution, Recoil, Coordinate system, Phase (waves), Atomic physics, Beam (structure), lcsh:Physics, lcsh:QC1-999
Abstract

In Fig. 5 on p. 311 of our Phys. Lett. B 740 (2015) 303 an adjustment by 180 ∘ is required for the phases with respect to the L = 2 , M = 1 wave, of the following waves: L = 1 , 3 , 5 with M = 1 , and L = 2 with M = 2 . After this correction (Fig. 5 (corrected) below), the extracted partial waves describe the angular distribution of the η ( ′ ) in the Gottfried-Jackson (GJ) frame, using Eq. (4) with implicit Condon-Shortley phase convention. The other results of our paper are not affected. The right-handed GJ coordinate system was defined by the z-axis pointing in the direction of the beam in the η ( ′ ) π − center-of-mass system and the y-axis pointing in the direction of p recoil GJ × p beam GJ .

Published
2020

15. K− over K+ multiplicity ratio for kaons produced in DIS with a large fraction of the virtual-photon energy

Author

S. Gerassimov, N. Horikawa, A. Srnka, A.G. Olshevsky, A. Rychter, F. Tosello, S. Tessaro, D. Hahne, R. Longo, M. Wilfert, V.N. Kolosov, L. Capozza, K. Kondo, F. Krinner, Yu.A. Khokhlov, Y.-S. Lian, C. Quintans, Alexandr Selyunin, Andrea Ferrero, I. Konorov, Y. Bedfer, K. Zaremba, C. Regali, C. Chatterjee, T. Sawada, Norihiro Doshita, V.A. Polyakov, Nour Makke, W. C. Chang, N. d'Hose, F. Kunne, Valery E. Lyubovitskij, C. Franco, R.R. Dusaev, V. Tskhay, Z.V. Kroumchtein, M. Chiosso, G. Sbrizzai, M. Quaresma, J. Barth, J. Smolik, E. Seder, J.F.C.A. Veloso, S.A. Mamon, O. Subrt, A. Amoroso, C.-Y. Hsieh, L. Dhara, B. Badełek, M. Ziembicki, Franco Bradamante, F. Pereira, N. du Fresne von Hohenesche, O.M. Kouznetsov, M. Stolarski, T. Szameitat, M. Grosse Perdekamp, B.M. Veit, A. Grasso, A. Gridin, A. Vidon, B. Marianski, Bakur Parsamyan, W. Augustyniak, S. Ramos, D.V. Peshekhonov, G. Pesaro, S. Platchkov, P. Zavada, Maria Liz Crespo, Miroslav Sulc, A. Kveton, Y. Miyachi, A.A. Lednev, P. Schiavon, M. A. Faessler, G.V. Khaustov, V. Frolov, B. Ketzer, Soumen Paul, R. Birsa, Jen-Chieh Peng, J. Lichtenstadt, P. Sznajder, J. Pochodzalla, V. Jary, Anne-Laure Martin, P. Jörg, S.S. Dasgupta, I. Gnesi, H. Schmieden, D. Steffen, Andrew Ivanov, S. Sarkar, Yu. Kisselev, O.P. Gavrichtchouk, Martin Bodlak, J.M. Friedrich, A. Sandacz, A. Vauth, H. Matsuda, R. Salac, M. Ostrick, S. Levorato, L. Sinha, T. Matsuda, D. Neyret, S. Dasgupta, A. Austregesilo, P. Bordalo, R. Akhunzyanov, Laura Silva, V.F. Konstantinov, Yakov Petrovich Kulinich, E.R. Bielert, D.I. Ryabchikov, A. Thiel, Q. Curiel, V.E. Burtsev, N. Mitrofanov, S. Huber, S. Wallner, E.A. Levchenko, S. Ishimoto, D. von Harrach, H. Fischer, E. M. Kabuß, E. Zemlyanichkina, Naomi C R Makins, G. D. Alexeev, R.P. Kurjata, Jan Tomsa, M. V. Zavertyaev, W. Dünnweber, K. Bicker, I.A. Savin, C. Marchand, M. Büchele, M.G. Alexeev, M. Krämer, S. Uhl, M. Finger, G. Hamar, J. Giarra, A.V. Efremov, Ilya Kuznetsov, J.H. Koivuniemi, Michal Dziewiecki, Andres Cicuttin, A. Moretti, I. Orlov, V.D. Samoylenko, Jan Matousek, G. Reicherz, Nikolay Anfimov, M. Pešková, M. Gorzellik, R. Heitz, M. Virius, J. Nový, R. Joosten, O.Yu. Denisov, Z. Kral, S. Dalla Torre, A. Antoshkin, P.D. Eversheim, F. Klein, Kamil Augsten, S.-U. Chung, G.V. Meshcheryakov, H. Suzuki, C.D.R. Azevedo, Yu. V. Mikhailov, R. Beck, A. Kerbizi, S. Sirtl, A. Maggiora, F. Tessarotto, Mikhail Mikhasenko, F. Nerling, François Herrmann, B. Grube, Johannes Bernhard, Ch. Dreisbach, S. V. Donskov, A. Guskov, M. Pešek, A.S. Nunes, Andrea Bressan, Markus Ball, D. Panzieri, Janusz Marzec, M. Tasevsky, E. Mitrofanov, G. Nukazuka, M. Slunecka, A. Magnon, Takahiro Iwata, Federica Sozzi, W. Meyer, K. Kurek, Gerhard K. Mallot, Aram Kotzinian, R. Windmolders, B.I. Vasilishin, M. Meyer, A.G. Chumakov, J. Pretz, Arseniy Rybnikov, W.-D. Nowak, V. Anosov, V. Andrieux, Adam Szabelski, A. Nagaytsev, F. Balestra, N. Pierre, F. Gautheron, C. Riedl, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, COMPASS, Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Akhunzyanov, R., Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Antoshkin, A., Augsten, K., Augustyniak, W., Austregesilo, A., Azevedo, C. D. R., Badełek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., Bernhard, J., Bicker, K., Bielert, E. R., Birsa, R., Bodlak, M., Bordalo, P., Bradamante, F., Bressan, A., Büchele, M., Burtsev, V. E., Capozza, L., Chang, W. -C., Chatterjee, C., Chiosso, M., Chumakov, A. G., Chung, S. -U., Cicuttin, A., Crespo, M. L., Curiel, Q., Dalla Torre, S., Dasgupta, S. S., Dasgupta, S., Denisov, O. Yu., Dhara, L., Donskov, S. V., Doshita, N., Dreisbach, Ch., Dünnweber, W., Dusaev, R. R., Dziewiecki, M., Efremov, A., Eversheim, P. D., Faessler, M., Ferrero, A., Finger, M., Fischer, H., Franco, C., du Fresne von Hohenesche, N., Friedrich, J. M., Frolov, V., Gautheron, F., Gavrichtchouk, O. P., Gerassimov, S., Giarra, J., Gnesi, I., Gorzellik, M., Grasso, A., Gridin, A., Grosse Perdekamp, M., Grube, B., Guskov, A., Hahne, D., Hamar, G., von Harrach, D., Heitz, R., Herrmann, F., Horikawa, N., D'Hose, N., Hsieh, C. -Y., Huber, S., Ishimoto, S., Ivanov, A., Iwata, T., Jary, V., Joosten, R., Jörg, P., Kabuß, E., Kerbizi, A., Ketzer, B., Khaustov, G. V., Khokhlov, Yu. A., Kisselev, Yu., Klein, F., Koivuniemi, J. H., Kolosov, V. N., Kondo, K., Konorov, I., Konstantinov, V. F., Kotzinian, A. M., Kouznetsov, O. M., Kral, Z., Krämer, M., Krinner, F., Kroumchtein, Z. V., Kulinich, Y., Kunne, F., Kurek, K., Kurjata, R. P., Kuznetsov, I. I., Kveton, A., Lednev, A. A., Levchenko, E. A., Levorato, S., Lian, Y. -S., Lichtenstadt, J., Longo, R., Lyubovitskij, V. E., Maggiora, A., Magnon, A., Makins, N., Makke, N., Mallot, G. K., Mamon, S. A., Marchand, C., Marianski, B., Martin, A., Marzec, J., Matoušek, J., Matsuda, H., Matsuda, T., Meshcheryakov, G. V., Meyer, M., Meyer, W., Mikhailov, Yu. V., Mikhasenko, M., Mitrofanov, E., Mitrofanov, N., Miyachi, Y., Moretti, A., Nagaytsev, A., Nerling, F., Neyret, D., Nový, J., Nowak, W. -D., Nukazuka, G., Nunes, A. S., Olshevsky, A. G., Orlov, I., Ostrick, M., Panzieri, D., Parsamyan, B., Paul, S., Peng, J. -C., Pereira, F., Pesaro, G., Pešek, M., Pešková, M., Peshekhonov, D. V., Pierre, N., Platchkov, S., Pochodzalla, J., Polyakov, V. A., Pretz, J., Quaresma, M., Quintans, C., Ramos, S., Regali, C., Reicherz, G., Riedl, C., Ryabchikov, D. I., Rybnikov, A., Rychter, A., Salac, R., Samoylenko, V. D., Sandacz, A., Sarkar, S., Savin, I. A., Sawada, T., Sbrizzai, G., Schiavon, P., Schmieden, H., Seder, E., Selyunin, A., Silva, L., Sinha, L., Sirtl, S., Slunecka, M., Sozzi, F., Smolik, J., Srnka, A., Steffen, D., Stolarski, M., Subrt, O., Sulc, M., Suzuki, H., Szabelski, A., Szameitat, T., Sznajder, P., Tasevsky, M., Tessaro, S., Tessarotto, F., Thiel, A., Tomsa, J., Tosello, F., Tskhay, V., Uhl, S., Vasilishin, B. I., Vauth, A., Veit, B. M., Veloso, J., Vidon, A., Virius, M., Wallner, S., Wilfert, M., Windmolders, R., Zaremba, K., Zavada, P., Zavertyaev, M., Zemlyanichkina, E., and Ziembicki, M.

Subjects
Hadron, 0 [higher-order], target: isoscalar, 01 natural sciences, COMPASS, deep inelastic scattering [muon+ nucleon], High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), K: multiplicity, High Energy Physics - Phenomenology (hep-ph), [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], isoscalar [target], Invariant mass, Nuclear Experiment, Boson, Physics, Quantum chromodynamics, quark: fragmentation function, higher-order: 0, photon, perturbation theory: higher-order, hep-ph, мюоны, lcsh:QC1-999, Bjorken [scaling], High Energy Physics - Phenomenology, beam [muon], рассеяние, factorization [cross section], multiplicity [pi], Particle Physics - Experiment, perturbation theory [quantum chromodynamics], Particle physics, Nuclear and High Energy Physics, Meson, FOS: Physical sciences, ratio [multiplicity], fragmentation function [quark], x-dependence, scaling: Bjorken, charged particle: multiplicity, phase space, multiplicity [charged particle], [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], виртуальные фотоны, 0103 physical sciences, ddc:530, universality, quantum chromodynamics: perturbation theory, 010306 general physics, Particle Physics - Phenomenology, muon+ nucleon: deep inelastic scattering, Muon, multiplicity: ratio, pi: multiplicity, 010308 nuclear & particles physics, hep-ex, muon: beam, Multiplicity (mathematics), cross section: factorization, CERN SPS, Deep inelastic scattering, higher-order [perturbation theory], [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], каоны, [ PHYS.HPHE ] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, multiplicity [K], hadronization, lcsh:Physics, experimental results
Abstract

The K$^{-}$ over K$^{+}$ multiplicity ratio is measured in deep-inelastic scattering, for the first time for kaons carrying a large fraction $z$ of the virtual-photon energy. The data were obtained by the COMPASS collaboration using a 160 GeV muon beam and an isoscalar $^6$LiD target. The regime of deep-inelastic scattering is ensured by requiring $Q^2>1$ (GeV/$c)^2$ for the photon virtuality and $W>5$ GeV/$c^2$ for the invariant mass of the produced hadronic system. Kaons are identified in the momentum range from 12 GeV/$c$ to 40 GeV/$c$, thereby restricting the range in Bjorken-$x$ to $0.010.75$. For very large values of $z$, $i.e.$ $z>0.8$, we observe the kaon multiplicity ratio to fall below the lower limits expected from calculations based on leading and next-to-leading order perturbative quantum chromodynamics. Also, the kaon multiplicity ratio shows a strong dependence on the missing mass of the single-kaon production process. This suggests that within the perturbative quantum chromodynamics formalism an additional correction may be required, which takes into account the phase space available for hadronisation., Comment: 16 pages, 7 figures

Published
2018
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16. Search for muoproduction of X(3872) at COMPASS and indication of a new state X˜(3872)

Author

L. Silva, S.S. Dasgupta, A.G. Chumakov, J. Nový, Y. Miyachi, P.D. Eversheim, P. Zavada, E. Zemlyanichkina, François Herrmann, S. Uhl, Y. Bedfer, A. Antoshkin, G. Sbrizzai, N.S. Rogacheva, A. Ferrero, G.V. Khaustov, A. Magnon, F. Pereira, I. Konorov, J. ter Wolbeek, Maria Liz Crespo, C. Regali, J. Marzec, A. Kveton, G.D. Alexeev, K. Schmidt, P. Kremser, O.Yu. Denisov, F. Gautheron, F. Nerling, Yu.A. Khokhlov, K. Kondo, N. C. R. Makins, M. Faessler, V.N. Kolosov, A. Amoroso, H. Matsuda, D. Neyret, C.D.R. Azevedo, V. Jary, V. Anosov, M. Grosse Perdekamp, S. Sarkar, Y.-S. Lian, R. Beck, A. Selyunin, B. Grube, M. Stolarski, M. Tasevsky, T. Sawada, N. Horikawa, M. Sulc, S. Tessaro, D. Hahne, V.D. Samoylenko, J. Giarra, N. d'Hose, W. Meyer, R. Joosten, Andres Cicuttin, O. Subrt, S. Wallner, S. Platchkov, R. Salac, Jen-Chieh Peng, V.A. Polyakov, J. Veloso, N. Zhuravlev, G.V. Meshcheryakov, A. Sandacz, M. Virius, F. H. Heinsius, S. Ishimoto, M. Aghasyan, A.M. Kotzinian, M. Zavertyaev, Jan Matousek, G. Reicherz, S. Dalla Torre, C. Quintans, M. Pešek, J. Barth, Alan D. Martin, M. Chiosso, N.V. Anfimov, Jan Tomsa, M. Ostrick, R.P. Kurjata, M. Finger, E. Kabuß, R.R. Dusaev, A.S. Nunes, T. Weisrock, R. Birsa, K. Augsten, V. Frolov, A. Maggiora, A. Vauth, A.A. Lednev, V.E. Lyubovitskij, C. Chatterjee, P. Jörg, Yakov Petrovich Kulinich, Gerhard K. Mallot, Andrey Ivanov, Frank Klein, P. Bordalo, A. Nagaytsev, Johannes Bernhard, Ch. Dreisbach, D. Panzieri, K. Zaremba, E.R. Bielert, Markus F. Krämer, J. Pochodzalla, K. Königsmann, M. Slunecka, A. Guskov, J.M. Friedrich, A. Srnka, H. Suzuki, S. Dasgupta, B. Marianski, T. Grussenmeyer, A. Rybnikov, Andrea Bressan, Anatoli Vasilievich Efremov, L. Dhara, T. Matsuda, M. Meyer, M. Dziewiecki, Markus Ball, M. Gorzellik, W.-D. Nowak, Yu. Kisselev, P. Schiavon, C. Santos, E. Mitrofanov, Bakur Parsamyan, W. Dünnweber, Martin Bodlak, Yu. Ivanshin, M.G. Alexeev, Ilya Kuznetsov, W. C. Chang, S.V. Donskov, D. Steffen, M. Wilfert, J. Smolik, K. Bicker, S. Ramos, L. Sinha, J. Pretz, E. Fuchey, S. Levorato, A. Austregesilo, A. Gridin, I. J. Choi, N. Mitrofanov, C. Franco, Stephan M. Paul, M. Levillain, A. Thiel, C. Riedl, V. Andrieux, Mikhail Mikhasenko, F. Krinner, I.A. Savin, O.P. Gavrichtchouk, N. Makke, I. Orlov, A. Szabelski, F. Giordano, E.A. Levchenko, N. du Fresne von Hohenesche, S. Gerassimov, N. Pierre, R. Longo, M. Quaresma, N. Doshita, B. Ketzer, A. Vidon, Yu.V. Mikhailov, I. Gnesi, G. Hamar, V.F. Konstantinov, P. Sznajder, Z. Kral, T. Iwata, B.I. Vasilishin, A. Grasso, V. Tskhay, H. Fischer, M. Ziembicki, M. Büchele, A. Rychter, S. Sirtl, Z.V. Kroumchtein, F. Balestra, S.-U. Chung, F. Tosello, T. Szameitat, D. von Harrach, K. Schönning, F. Tessarotto, J.H. Koivuniemi, Franco Bradamante, A. Kerbizi, J. Lichtenstadt, F. Kunne, M. Pešková, E. Seder, K. Kurek, G. Nukazuka, D.V. Peshekhonov, R. Heitz, O.M. Kouznetsov, V.E. Burtsev, R. Akhunzyanov, S.A. Mamon, H. Schmieden, C.-Y. Hsieh, B. Badełek, W. Augustyniak, D.I. Ryabchikov, A.G. Olshevsky, and S. Huber

Subjects
Physics, Nuclear and High Energy Physics, Muon, Mass distribution, 010308 nuclear & particles physics, Branching fraction, Hadron, State (functional analysis), 01 natural sciences, Momentum, 0103 physical sciences, Tetraquark, Atomic physics, 010306 general physics, X(3872)
Abstract

We have searched for exclusive production of exotic charmonia in the reaction μ + N → μ + ( J / ψ π + π − ) π ± N ′ using COMPASS data collected with incoming muons of 160 GeV/c and 200 GeV/c momentum. In the J / ψ π + π − mass distribution we observe a signal with a statistical significance of 4.1 σ. Its mass and width are consistent with those of the X ( 3872 ) . The shape of the π + π − mass distribution from the observed decay into J / ψ π + π − shows disagreement with previous observations for X ( 3872 ) . The observed signal may be interpreted as a possible evidence of a new charmonium state. It could be associated with a neutral partner of X ( 3872 ) with C = − 1 predicted by a tetraquark model. The product of cross section and branching fraction of the decay of the observed state into J / ψ π + π − is determined to be 71±28(stat)±39(syst) pb.

Published
2018
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17. The spin structure functiong1pof the proton and a test of the Bjorken sum rule

Author

N.S. Rossiyskaya, F. Giordano, F. Haas, A. Grasso, V. Anosov, A.G. Olshevsky, F. Tessarotto, Laura Silva, C. Riedl, S. Ramos, Fabrice Gautheron, Q. Curiel, D. Neyret, L. Capozza, K. Kondo, A. Srnka, P. Sznajder, R. Jahn, A. Lehmann, J. Pretz, V. Andrieux, K. Bicker, P.D. Eversheim, J. Lichtenstadt, Adam Szabelski, K. Klimaszewski, M. Büchele, Andres Cicuttin, H. Suzuki, I. Orlov, C.D.R. Azevedo, V.D. Samoylenko, G. Reicherz, S. Dalla Torre, O.Yu. Denisov, K. Zaremba, F. Kunne, J.H. Koivuniemi, W.-D. Nowak, P. Kremser, V.A. Polyakov, D.I. Ryabchikov, G. Sbrizzai, M. Levillain, E. M. Kabuß, A. Nagaytsev, Yu. Kisselev, V. Frolov, E. Burtin, A. Amoroso, V.F. Konstantinov, Takahiro Iwata, F. Balestra, M. Ostrick, Soumen Paul, R. Beck, S. Ishimoto, M. Stolarski, Jen-Chieh Peng, H. Fischer, E. Rocco, E.R. Bielert, R. Joosten, C. Adolph, R. Akhunzyanov, G. Baum, I.A. Savin, Andrea Ferrero, Miroslav Sulc, Bakur Parsamyan, F. Hinterberger, V. Tskhay, G. D. Alexeev, E. Fuchey, R.P. Kurjata, I. J. Choi, A.B. Ivanov, M. Boer, S. Dasgupta, A. Austregesilo, A.V. Efremov, O.P. Gavrichtchouk, F. Krinner, Martin Bodlak, M. Finger, L. Sinha, Aram Kotzinian, S. G. Gerassimov, T. Matsuda, Johannes Bernhard, Jan Matousek, A. Guskov, A. Zink, Frank Klein, Andrea Bressan, Alexandr Selyunin, R. Windmolders, M. Chiosso, A. Magnon, R. Birsa, M. Gorzellik, Yu. Ivanshin, M. Krämer, W. Meyer, Maria Liz Crespo, V.I. Nikolaenko, M.G. Alexeev, S. Uhl, S. Sarkar, G.V. Meshcheryakov, Michal Dziewiecki, K. Kurek, V. Jary, M. Ziembicki, Yu. V. Mikhailov, S. Sirtl, B. Grube, W. Eyrich, Nour Makke, F. H. Heinsius, W. C. Chang, Y. Bedfer, S.-U. Chung, D. von Harrach, S. V. Donskov, M. Pešek, A.S. Nunes, C.-Yu. Hsieh, François Herrmann, G.V. Khaustov, D. Panzieri, Janusz Marzec, I. Konorov, M. Quaresma, T. Grussenmeyer, D.V. Peshekhonov, M. Slunecka, T. Szameitat, Federica Sozzi, S. Schopferer, I. Gnesi, J. ter Wolbeek, Z.V. Kroumchtein, N. du Fresne von Hohenesche, F. Thibaud, J. Barth, Gerhard K. Mallot, T. Weisrock, N. Horikawa, F. Tosello, S. Tessaro, D. Hahne, P. Schiavon, Yu.A. Khokhlov, H. Matsuda, M. Wilfert, C. Quintans, O. Kouznetsov, Franco Bradamante, J.F.C.A. Veloso, V. Duic, Alan D. Martin, S.S. Dasgupta, M. V. Zavertyaev, H. Schmieden, R. Hashimoto, J.M. Friedrich, N. Kuchinski, J. Bisplinghoff, S. Huber, C. Marchand, E. Zemlyanichkina, C. Regali, A. Rychter, R. Longo, V.N. Kolosov, K. Schönning, K. Königsmann, S. Platchkov, F. Nerling, J. Novy, C. Franco, A. Maggiora, Celso Augusto Guimarães Santos, S. Grabmüller, K. Schmidt, Norihiro Doshita, N. d'Hose, J. Pochodzalla, P. Bordalo, T. Nagel, L. Dhara, C. Braun, Y. Miyachi, A.A. Lednev, T. Michigami, B. Badelek, A. Sandacz, B. Ketzer, S. Takekawa, F. Pereira, M. Virius, P. Jörg, O.Yu. Shevchenko, S. Levorato, M. Grosse-Perdekamp, and Naomi C R Makins

Subjects
Physics, Quantum chromodynamics, Nuclear and High Energy Physics, Particle physics, Muon, Proton, 010308 nuclear & particles physics, Deep inelastic scattering, 01 natural sciences, Helicity, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Sum rule in quantum mechanics, 010306 general physics, Nucleon, Spin-½
Abstract

New results for the double spin asymmetry A(1)(p) and the proton longitudinal spin structure function g(1)(p) are presented. They were obtained by the COMPASS Collaboration using polarised 200 GeV muons scattered off a longitudinally polarised NH3 target. The data were collected in 2011 and complement those recorded in 2007 at 160 GeV, in particular at lower values of x. They improve the statistical precision of g(1)(p)(x) by about a factor of two in the region x less than or similar to 0.02. A next-to-leading order QCD fit to the g(1) world data is performed. It leads to a new determination of the quark spin contribution to the nucleon spin, Delta Sigma, ranging from 0.26 to 0.36, and to a re-evaluation of the first moment of g(1)(p). The uncertainty of Delta Sigma is mostly due to the large uncertainty in the present determinations of the gluon helicity distribution. A new evaluation of the Bjorken sum rule based on the COMPASS results for the non-singlet structure function g(1)(NS) (x, Q(2)) yields as ratio of the axial and vector coupling constants vertical bar gA/gV vertical bar = 1.22 +/- 0.05 (stat.) +/- 0.10 (syst.), which validates the sum rule to an accuracy of about 9%.

Published
2016
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18. Transverse target spin asymmetries in exclusive ρ0 muoproduction

Author

C. Adolph, R. Akhunzyanov, M.G. Alekseev, V.Yu. Alexakhin, Yu. Alexandrov, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Austregesilo, B. Badełek, F. Balestra, J. Barth, G. Baum, R. Beck, Y. Bedfer, A. Berlin, J. Bernhard, R. Bertini, K. Bicker, J. Bieling, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bravar, A. Bressan, M. Büchele, E. Burtin, L. Capozza, M. Chiosso, S.U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, C. Elia, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, A. Filin, M. Finger, H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, R. Garfagnini, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, R. Geyer, M. Giorgi, I. Gnesi, B. Gobbo, S. Goertz, M. Gorzellik, S. Grabmüller, A. Grasso, B. Grube, R. Gushterski, A. Guskov, T. Guthörl, F. Haas, D. von Harrach, D. Hahne, R. Hashimoto, F.H. Heinsius, F. Herrmann, C. Heß, F. Hinterberger, Ch. Höppner, N. Horikawa, N. d'Hose, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, P. Jasinski, P. Joerg, R. Joosten, E. Kabuß, D. Kang, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, Z. Kral, M. Krämer, Z.V. Kroumchtein, N. Kuchinski, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, S. Levorato, J. Lichtenstadt, A. Maggiora, A. Magnon, N. Makke, G.K. Mallot, C. Marchand, A. Martin, J. Marzec, J. Matousek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, Y. Miyachi, A. Nagaytsev, T. Nagel, F. Nerling, S. Neubert, D. Neyret, V.I. Nikolaenko, J. Novy, W.-D. Nowak, A.S. Nunes, I. Orlov, A.G. Olshevsky, M. Ostrick, R. Panknin, D. Panzieri, B. Parsamyan, S. Paul, M. Pesek, D. Peshekhonov, G. Piragino, S. Platchkov, J. Pochodzalla, J. Polak, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, G. Reicherz, E. Rocco, V. Rodionov, E. Rondio, N.S. Rossiyskaya, D.I. Ryabchikov, V.D. Samoylenko, A. Sandacz, M.G. Sapozhnikov, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, C. Schill, T. Schlüter, A. Schmidt, K. Schmidt, L. Schmitt, H. Schmïden, K. Schönning, S. Schopferer, M. Schott, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, S. Sosio, F. Sozzi, A. Srnka, L. Steiger, M. Stolarski, M. Sulc, R. Sulej, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, J. Ter Wolbeek, S. Tessaro, F. Tessarotto, F. Thibaud, S. Uhl, I. Uman, M. Vandenbroucke, M. Virius, J. Vondra, L. Wang, T. Weisrock, M. Wilfert, R. Windmolders, W. Wiślicki, H. Wollny, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, and M. Ziembicki

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Muon, Meson, 010308 nuclear & particles physics, media_common.quotation_subject, Hadron, Elementary particle, Parton, 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, media_common, Lepton
Abstract

COMPASS has studied exclusive production of ρ 0 mesons using a 160 GeV/ c muon beam and a transversely polarised NH 3 target. Five single-spin and three double-spin azimuthal aymmetries were measured in dependence on Q 2 , x Bj , or p T 2 . Except the sin ϕ S asymmetry, obtained to be − 0.019 ± 0.008( stat .) ± 0.003( syst .), all others were found to be consistent with zero within experimental uncertainties. Phenomenological GPD-based model calculations agree well with the data and interpret the result as evidence for the existence of chiral-odd, transverse generalised parton distributions.

Published
2014
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19. Leading order determination of the gluon polarisation from DIS events with high-pThadron pairs

Author

S. Koblitz, S. Ramos, F. Haas, R. Geyer, R. Panknin, E. Rondio, Fabrice Gautheron, M. A. Faessler, V.Yu. Alexakhin, J. Polak, V.N. Kolosov, Christian Schill, N.S. Rossiyskaya, F. Kunne, R. Jahn, F. Tessarotto, C. Heß, C. Adolph, A. Korzenev, A. Grasso, J. M. Le Goff, D. Chaberny, V. Duic, E. M. Kabuß, O.P. Gavrichtchouk, A.A. Lednev, A. Nagaytsev, F. Balestra, A. Srnka, L. Sinha, T. Matsuda, G. D. Alexeev, F. Nerling, A.V. Efremov, W. Dünnweber, Yu.V. Mikhailov, R. Gushterski, Yu. Alexandrov, Yu. Kisselev, George I. Smirnov, S. Hedicke, Z.V. Kroumchtein, I.A. Savin, S. Grabmüller, I. Konorov, W.-D. Nowak, O.Yu. Denisov, A. Zvyagin, M. Ostrick, Bakur Parsamyan, C. Quintans, K. Zaremba, Alessandro Bressan, D. von Harrach, S. Gerassimov, G. Piragino, T. Guthörl, N. Horikawa, Sergey Donskov, L. Dhara, S. Ishimoto, Frank Klein, C. Braun, V.A. Polyakov, G. Sbrizzai, Ch. Höppner, A. Amoroso, S. Uhl, S.U. Chung, L. Schmitt, Oleg V. Ivanov, Maxence Vandenbroucke, B. Badelek, R. Birsa, Matthias Schott, N. du Fresne von Hohenesche, T. Schlüter, M. Giorgi, Michal Dziewiecki, E. Perevalova, S. Tessaro, E. Rocco, A. Richter, K. Klimaszewski, S. Das, R. Gazda, M. Chiosso, A.G. Olshevsky, Laura Silva, B. Ketzer, I. Uman, A. Morreale, Andres Cicuttin, A. Filin, A. Magnon, G. Reicherz, R. Joosten, V.D. Samoylenko, K. Kurek, A. Padee, L. G. Tkatchev, Yu.A. Khokhlov, D. Neyret, S. Paul, J. Pochodzalla, M. Stolarski, J.M. Friedrich, K. Bicker, R. Bertini, Andrea Ferrero, S. Dalla Torre, J. Bisplinghoff, S. Huber, G.V. Khaustov, S.S. Dasgupta, A. Mutter, Jean-Francois Rajotte, D.I. Ryabchikov, A.S. Nunes, Vladimir Nikolaenko, Miroslav Sulc, Aram Kotzinian, F. Hinterberger, P. Bordalo, D. Kang, R. Windmolders, H. Wollny, D. Panzieri, L. Lauser, O. Kouznetsov, E. Zemlyanichkina, W. Meyer, Maria Liz Crespo, J. Lichtenstadt, J. Marzec, Yu. Ivanshin, M.G. Alekseev, P. Jasinski, Franco Bradamante, M. V. Zavertyaev, Anne-Laure Martin, K. Schönning, Alexey Antonov, A. Bravar, P. Sznajder, J. ter Wolbeek, Johannes Bernhard, J. Nassalski, S. Sosio, S. Takekawa, M. Bettinelli, Michael Kramer, A. Guskov, K. Kondo, J. Barth, Y. Bedfer, E. Burtin, V.F. Konstantinov, A. Lehmann, C. Franco, J.H. Koivuniemi, C. Marchand, Gerhard K. Mallot, S. Goertz, V. Rapatsky, Sarben Sarkar, H. Fischer, P. Schiavon, K. Königsmann, A. Maggiora, B. Grube, N. dʼHose, N.V. Vlassov, Günter Baum, O.Yu. Shevchenko, S. Levorato, R. Garfagnini, M. Finger, Murray Moinester, François Herrmann, S. Platchkov, Lei Wang, M. Slunecka, M. Virius, W. Wiślicki, G.B. Pontecorvo, B. Gobbo, N. I. Zhuravlev, Federica Sozzi, S. Schopferer, T. Nagel, J. Pretz, R. Sulej, S. Procureur, T. Michigami, A. Mann, W. Eyrich, Nour Makke, J. Bieling, A. Sandacz, M. Quaresma, M.G. Sapozhnikov, K. Schmidt, D.V. Peshekhonov, Norihiro Doshita, A. N. Sissakian, G. Pesaro, I. Gnesi, P.D. Eversheim, S. Neubert, T. Iwata, M. Ziembicki, F. H. Heinsius, A. Austregesilo, and C. Elia

Subjects
Physics, Quantum chromodynamics, Nuclear and High Energy Physics, Particle physics, Muon, Proton, 010308 nuclear & particles physics, Hadron, Deep inelastic scattering, 01 natural sciences, Gluon, Nuclear physics, 0103 physical sciences, COMPASS experiment, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

We present a determination of the gluon polarisation Delta g/g in the nucleon, based on the longitudinal double-spin asymmetry of DIS events with Q(2) > 1 (GeV/c)(2) including a pair of large transverse-momentum hadrons in the final state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV/c polarised muon beam scattering off a polarised (LiD)-Li-6 target. The gluon polarisation is evaluated by a Neural Network approach for three intervals of the gluon momentum fraction x(g) covering the range 0.04 < x(g) < 0.27. The values obtained at leading order in QCD do not show any significant dependence on x(g). Their average is Delta g/g = 0.125 +/- 0.060 (stat.) +/- 0.063 (syst.) at average x(g) = 0.09 and a scale of mu(2) = 3 (GeV/c)(2).

Published
2013
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20. Quark helicity distributions from longitudinal spin asymmetries in muon–proton and muon–deuteron scattering

Author

M.G. Alekseev, V.Yu. Alexakhin, Yu. Alexandrov, G.D. Alexeev, A. Amoroso, A. Austregesilo, B. Badełek, F. Balestra, J. Barth, G. Baum, Y. Bedfer, J. Bernhard, R. Bertini, M. Bettinelli, R. Birsa, J. Bisplinghoff, P. Bordalo, F. Bradamante, A. Bravar, A. Bressan, G. Brona, E. Burtin, M.P. Bussa, D. Chaberny, M. Chiosso, S.U. Chung, A. Cicuttin, M. Colantoni, M.L. Crespo, S. Dalla Torre, S. Das, S.S. Dasgupta, O.Yu. Denisov, L. Dhara, V. Diaz, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, A. Efremov, A. El Alaoui, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, A. Filin, M. Finger, H. Fischer, C. Franco, J.M. Friedrich, R. Garfagnini, F. Gautheron, O.P. Gavrichtchouk, R. Gazda, S. Gerassimov, R. Geyer, M. Giorgi, I. Gnesi, B. Gobbo, S. Goertz, S. Grabmüller, A. Grasso, B. Grube, R. Gushterski, A. Guskov, F. Haas, D. von Harrach, T. Hasegawa, F.H. Heinsius, F. Herrmann, C. Heß, F. Hinterberger, N. Horikawa, Ch. Höppner, N. d'Hose, C. Ilgner, S. Ishimoto, O. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, P. Jasinski, G. Jegou, R. Joosten, E. Kabuß, D. Kang, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, S. Koblitz, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, R. Konopka, I. Konorov, V.F. Konstantinov, A. Korzenev, A.M. Kotzinian, O. Kouznetsov, K. Kowalik, M. Krämer, A. Kral, Z.V. Kroumchtein, R. Kuhn, F. Kunne, K. Kurek, L. Lauser, J.M. Le Goff, A.A. Lednev, A. Lehmann, S. Levorato, J. Lichtenstadt, T. Liska, A. Maggiora, M. Maggiora, A. Magnon, N. Makke, G.K. Mallot, A. Mann, C. Marchand, A. Martin, J. Marzec, F. Massmann, T. Matsuda, W. Meyer, T. Michigami, Yu.V. Mikhailov, M.A. Moinester, A. Mutter, A. Nagaytsev, T. Nagel, J. Nassalski, T. Negrini, F. Nerling, S. Neubert, D. Neyret, V.I. Nikolaenko, A.S. Nunes, A.G. Olshevsky, M. Ostrick, A. Padee, R. Panknin, D. Panzieri, B. Parsamyan, S. Paul, B. Pawlukiewicz-Kaminska, E. Perevalova, G. Pesaro, D.V. Peshekhonov, G. Piragino, S. Platchkov, J. Pochodzalla, J. Polak, V.A. Polyakov, G. Pontecorvo, J. Pretz, C. Quintans, J.-F. Rajotte, S. Ramos, V. Rapatsky, G. Reicherz, A. Richter, F. Robinet, E. Rocco, E. Rondio, D.I. Ryabchikov, V.D. Samoylenko, A. Sandacz, H. Santos, M.G. Sapozhnikov, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, C. Schill, T. Schlüter, L. Schmitt, S. Schopferer, W. Schröder, O.Yu. Shevchenko, H.-W. Siebert, L. Silva, L. Sinha, A.N. Sissakian, M. Slunecka, G.I. Smirnov, S. Sosio, F. Sozzi, A. Srnka, M. Stolarski, M. Sulc, R. Sulej, S. Takekawa, S. Tessaro, F. Tessarotto, A. Teufel, L.G. Tkatchev, S. Uhl, I. Uman, M. Virius, N.V. Vlassov, A. Vossen, Q. Weitzel, R. Windmolders, W. Wiślicki, H. Wollny, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, J. Zhao, N. Zhuravlev, A. Zvyagin, M. G., Alekseev, Alexakhin, V. Y. u., Alexandrovo, Y. u., G. D., Alexeev, A., Amoroso, A., Austregesilo, B., Badełek, F., Balestra, J., Barth, G., Baum, Y., Bedfer, J., Bernhard, R., Bertini, M., Bettinelli, R., Birsa, J., Bisplinghoff, P., Bordalo, Bradamante, Franco, A., Bravar, Bressan, Andrea, G., Brona, E., Burtin, M. P., Bussa, D., Chaberny, M., Chiosso, S. U., Chung, A., Cicuttin, M., Colantoni, M. L., Crespo, S., Dalla Torre, S., Da, S. S., Dasgupta, Denisov, O. Y. u., L., Dhara, V., Diaz, S. V., Donskov, N., Doshita, Duic, Venicio, W., Dunnweber, A., Efremov, A., El Alaoui, P. D., Eversheim, W., Eyrich, M., Faessler, A., Ferrero, A., Filin, M., Finger, M. Finger J., R., H., Fischeri, C., Franco, J. M., Friedrich, R., Garfagnini, F., Gautheron, O. P., Gavrichtchouk, R., Gazda, S., Gerassimov, R., Geyer, Giorgi, Marcello, I., Gnesi, B., Gobbo, S., Goertz, S., Grabmuller, A., Grasso, B., Grube, R., Gushterski, A., Guskov, F., Haa, D., von Harrach, T., Hasegawa, F. H., Heinsiu, F., Herrmann, C., He, F., Hinterberger, N., Horikawa, Hoppner, C. h., N., D’Hose, C., Ilgnerj, S., Ishimoto, O., Ivanov, Ivanshin, Y. u., T., Iwata, R., Jahn, P., Jasinski, G., Jegou, R., Joosten, E., Kabu, D., Kang, B., Ketzer, G. V., Khaustov, Khokhlov, Y. u. A., Kisselev, Y. u., F., Klein, K., Klimaszewski, S., Koblitz, J. H., Koivuniemi, V. N., Kolosov, K., Kondo, K., Konigsmann, R., Konopka, I., Konorov, V. F., Konstantinov, A., Korzenev, A. M., Kotzinian, O., Kouznetsov, K., Kowalik, M., Kramer, A., Kral, Z. V., Kroumchtein, R., Kuhn, F., Kunne, K., Kurek, L., Lauseri, J. M., Le Goff, A. A., Lednev, A., Lehmann, Levorato, Stefano, J., Lichtenstadt, T., Liska, A., Maggiora, M., Maggiora, A., Magnon, N., Makke, G. K., Mallot, A., Mann, C., Marchand, Martin, Anna, J., Marzec, F., Massmann, T., Matsuda, W., Meyer, T., Michigami, Mikhailov, Y. u. V., M. A., Moinester, A., Mutteri, A., Nagaytsev, T., Nagel, J., Nassalski, T., Negrini, F., Nerling, S., Neubert, D., Neyret, V. I., Nikolaenko, A. S., Nune, A. G., Olshevsky, M., Ostrick, A., Padee, R., Panknin, D., Panzieri, B., Parsamyan, S., Paul, B., Pawlukiewicz Kaminska, E., Perevalova, Pesaro, Giulia, D. V., Peshekhonov, G., Piragino, S., Platchkov, J., Pochodzalla, J., Polak, V. A., Polyakov, G., Pontecorvo, J., Pretz, C., Quintan, J. F., Rajotte, S., Ramo, V., Rapatsky, G., Reicherz, A., Richter, F., Robinet, E., Rocco, E., Rondio, D. I., Ryabchikov, V. D., Samoylenko, A., Sandacz, H., Santo, M. G., Sapozhnikov, S., Sarkar, I. A., Savin, Sbrizzai, Giulio, Schiavon, Paolo, C., Schill, T., Schluter, L., Schmitt, S., Schopfereri, W., Schroder, Shevchenko, O. Y. u., H. W., Siebert, L., Silva, L., Sinha, A. N., Sissakian, M., Slunecka, G. I., Smirnov, S., Sosio, Sozzi, Federica, A., Srnka, M., Stolarskij, M., Sulc, R., Sulej, Takekawa, Stefano, S., Tessaro, F., Tessarotto, A., Teufel, L. G., Tkatchev, S., Uhl, I., Uman, M., Viriu, N. V., Vlassov, A., Vossen, Q., Weitzel, R., Windmolder, W., Wi´slicki, H., Wollny, K., Zaremba, M., Zavertyaev, E., Zemlyanichkina, M., Ziembicki, J., Zhao, N., Zhuravlev, and A., Zvyagin

Subjects
Quark, Nuclear and High Energy Physics, Proton, High Energy Physics::Lattice, media_common.quotation_subject, Nuclear Theory, FOS: Physical sciences, COMPASS, 01 natural sciences, Asymmetry, Semi-inclusive deep inelastic scattering, Spin, Structure function, Parton distribution functions, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, COMPASS experiment, Nuclear Experiment, 010306 general physics, Spin-½, media_common, Physics, function, Muon, 010308 nuclear & particles physics, Scattering, High Energy Physics::Phenomenology, Structure, Helicity, High Energy Physics::Experiment, Particle Physics - Experiment
Abstract

Double-spin asymmetries for production of charged pions and kaons in semi-inclusive deep-inelastic muon scattering have been measured by the COMPASS experiment at CERN. The data, obtained by scattering a 160 GeV muon beam off a longitudinally polarised NH_3 target, cover a range of the Bjorken variable x between 0.004 and 0.7. A leading order evaluation of the helicity distributions for the three lightest quarks and antiquark flavours derived from these asymmetries and from our previous deuteron data is presented. The resulting values of the sea quark distributions are small and do not show any sizable dependence on x in the range of the measurements. No significant difference is observed between the strange and antistrange helicity distributions, both compatible with zero. The integrated value of the flavour asymmetry of the helicity distribution of the light-quark sea, \Delta u-bar - \Delta d-bar, is found to be slightly positive, about 1.5 standard deviations away from zero., Comment: 13 pages, 5 figures

Published
2010
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21. The spin-dependent structure function of the proton g1p and a test of the Bjorken sum rule

Author

P. Schiavon, I. Konorov, C. Hess, Miroslav Sulc, M. Ziembicki, F. Hinterberger, F.H. Heinsius, Achim Richter, A. Magnon, F. Massmann, S. Ramos, Norihiro Doshita, N. d'Hose, Alan D. Martin, D. Kang, K. Königsmann, Soumen Paul, T. Hasegawa, E. Rondio, A. Austregesilo, R. Gazda, A. Maggiora, E. Perevalova, R. Kuhn, A. N. Sissakian, S. Das, A.G. Olshevsky, R. Jahn, A. Ferrero, A. Maximov, C. Quintans, D. Cotic, M.P. Bussa, V.D. Samoylenko, O.P. Gavrichtchouk, Vladimir A. Polyakov, D. Neyret, Elena Rocco, J. Polak, W. Kafer, J.H. Koivuniemi, R. Joosten, L. Sinha, S. Neubert, A. Korzenev, T. Matsuda, K. Zaremba, Laura Silva, A.A. Lednev, A. Mutter, A. Lehmann, J. Ball, J. M. Le Goff, S. Platchkov, O. Kouznetsov, Yu.V. Mikhailov, A. Král, R. Windmolders, S. Sarkar, R. Bertini, Franco Bradamante, B. Pawlukiewicz-Kaminska, S.S. Dasgupta, M. V. Zavertyaev, C. Marchand, V. Rapatsky, A. Nagaytsev, F. Balestra, A. Srnka, L. Lauser, S. Grabmüller, W. Wislicki, J. Pochodzalla, V. Duic, G. Sbrizzai, A. Padee, F. Tessarotto, Moinester, P. Jasinski, O.Yu. Denisov, V. Diaz, T. Negrini, J. Marzec, G. Piragino, S. Uhl, P.D. Eversheim, G.B. Pontecorvo, K. Klimaszewski, M. Maggiora, P. Bordalo, F. Nerling, A. Amoroso, M. Chiosso, F. Haas, R. Geyer, Jean-Francois Rajotte, Takahiro Iwata, D.I. Ryabchikov, D. von Harrach, M. Giorgi, A.S. Nunes, S. Koblitz, Andres Cicuttin, L. Schmitt, T. Nagel, D. Panzieri, J. Pretz, T. Schlüter, A. El Alaoui, S. Gerassimov, M. Krämer, N. Horikawa, J. Zhao, K. Kondo, M.G. Alekseev, Sergey Donskov, T. Liška, G. Reicherz, H.-W. Siebert, F. Kunne, R. Gushterski, W. Eyrich, M. Virius, S. Tessaro, V.F. Konstantinov, Johannes Bernhard, A. Guskov, Y. Bedfer, G.V. Khaustov, A. Zvyagin, T. Michigami, S. Dalla Torre, E. Burtin, H. Santos, Q. Weitzel, M. Bettinelli, M. Slunecka, A. Sandacz, B. Gobbo, I.A. Savin, Andrea Bressan, W. Schröder, N. I. Zhuravlev, Ch. Höppner, Yu.A. Khokhlov, A. M. Kotzinian, W. Meyer, Maria Liz Crespo, H. Fischer, M. L. Colantoni, C. Ilgner, J. Barth, R. Konopka, A. Teufel, S. Schopferer, N.V. Vlassov, Günter Baum, M.G. Sapozhnikov, O.Yu. Shevchenko, S. Levorato, Yu. Kisselev, D. Chaberny, S.-U. Chung, V.N. Kolosov, V.I. Nikolaenko, D.V. Peshekhonov, J. Marroncle, A.V. Efremov, R. Garfagnini, Z.V. Kroumchtein, François Herrmann, A. Bravar, A. Mann, M. Ostrick, G. Jegou, K. Kurek, E. Kabuss, Oleg V. Ivanov, R. Hermann, H. Wollny, S. Sosio, Christian Schill, I. Uman, G. Pesaro, S. Takekawa, Yu. Alexandrov, J. Lichtenstadt, M. Stolarski, I. Gnesi, Bakur Parsamyan, G.I. Smirnov, Fabrice Gautheron, M. A. Faessler, R. Panknin, V.Yu. Alexakhin, A. Grasso, R. Sulej, M. Finger, C. Franco, R. Birsa, G. D. Alexeev, W. Dünnweber, J.M. Friedrich, J. Bisplinghoff, E. Zemlyanichkina, L. Dhara, B. Badelek, B. Ketzer, F. Robinet, A. Filin, Grzegorz Brona, Gerhard K. Mallot, A. Vossen, F. Sozzi, J. Nassalski, S. Ishimoto, Frank Klein, K. Kowalik, Yu. Ivanshin, L. G. Tkatchev, S. Goertz, and B. Grube

Subjects
Quantum chromodynamics, Physics, Coupling constant, Nuclear and High Energy Physics, Particle physics, Muon, Isovector, Proton, 010308 nuclear & particles physics, Deep inelastic scattering, 01 natural sciences, Nuclear physics, 0103 physical sciences, Sum rule in quantum mechanics, 010306 general physics, Spin-½
Abstract

The inclusive double-spin asymmetry, A 1 p , has been measured at COMPASS in deep-inelastic polarised muon scattering off a large polarised NH3 target. The data, collected in the year 2007, cover the range Q 2 > 1 ( GeV / c ) 2 , 0.004 x 0.7 and improve the statistical precision of g 1 p ( x ) by a factor of two in the region x 0.02 . The new proton asymmetries are combined with those previously published for the deuteron to extract the non-singlet spin-dependent structure function g 1 NS ( x , Q 2 ) . The isovector quark density, Δ q 3 ( x , Q 2 ) , is evaluated from a NLO QCD fit of g 1 NS . The first moment of Δ q 3 is in good agreement with the value predicted by the Bjorken sum rule and corresponds to a ratio of the axial and vector coupling constants | g A / g V | = 1.28 ± 0.07 ( stat . ) ± 0.10 ( syst. ) .

Published
2010
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22. Spin asymmetry A1d and the spin-dependent structure function g1d of the deuteron at low values of x and Q2

Author

Aram Kotzinian, R. Windmolders, M.G. Sapozhnikov, S. Neliba, L. Schmitt, A. Janata, J. Zhao, E. Burtin, J. Lichtenstadt, R. Geyer, D.V. Peshekhonov, P. Schiavon, V.F. Konstantinov, Q. Weitzel, J. Pretz, L. Ferrero, H. Fischer, A.G. Olshevsky, T. Hasegawa, S. Procureur, R. Ziegler, Yu. Alexandrov, A. Chapiro, M. Fabro, V.F. Obraztsov, M. Maggiora, K. Zaremba, D. Neyret, G.I. Smirnov, Fabrice Gautheron, M. A. Faessler, V.A. Polyakov, R. C. Webb, A. Mielech, S. Ishimoto, Frank Klein, Andres Cicuttin, A. Amoroso, G. Reicherz, J. Marzec, St. Goertz, V.Yu. Alexakhin, A. Korzenev, Colin Bernet, Massimo Lamanna, Yu. Kisselev, A. Sandacz, A. Srnka, R. Sulej, C. Ilgner, S. Platchkov, S. Dalla Torre, V.P. Sugonyaev, N.P. Kravchuk, A. Bravar, M. Ostrick, I. Konorov, M. Stolarski, C. Quintans, Grzegorz Brona, Gerhard K. Mallot, A. Zvyagin, Murray Moinester, S. Ramos, Alessandro Bressan, F. Tessarotto, E. M. Kabuß, A.M. Rozhdestvensky, N. V. Khomutov, A. Gorin, I.A. Savin, T. Matsuda, T. Iwata, Z.V. Kroumchtein, F. Sozzi, D. von Harrach, F. Balestra, Franco Bradamante, F.H. Heinsius, Norihiro Doshita, S. Gerassimov, W. Eyrich, J. Ball, L. G. Tkatchev, V. Falaleev, N. Horikawa, H.-W. Siebert, Yu.V. Mikhailov, S. Koblitz, N. d'Hose, E.V. Komissarov, A. Grasso, Sergey Donskov, S. Paul, V. Diaz Kavka, R. Jahn, A. Magnon, A. N. Sissakian, B. Grube, D. Panzieri, J. Nassalski, O.Yu. Denisov, T. Liška, Yu.A. Khokhlov, I. Ludwig, R. Joosten, K. Kurek, G. D. Alexeev, O.A. Grajek, Miroslav Sulc, F. Hinterberger, C. Marchand, A. Maximov, W. Dünnweber, M. Virius, J.M. Friedrich, V.D. Samoylenko, E. Weise, J. Pochodzalla, M.L. Colantoni, S. Hedicke, O.P. Gavrichtchouk, L. Sinha, J. Marroncle, S.S. Dasgupta, N. Takabayashi, J. Bisplinghoff, A.I. Ioukaev, E. Rondio, K. Kondo, R. De Masi, P. Bordalo, M.P. Bussa, A.A. Shishkin, G.V. Khaustov, Alan D. Martin, J. Heckmann, J. Franz, S. Wirth, Y. Bedfer, J. Hannappel, Paolo Pagano, Vladimir Peshekhonov, J. M. Le Goff, R. Birsa, N.I. Jouravlev, S. Horikawa, P.D. Eversheim, G. Piragino, V. Duic, W. Meyer, Maria Liz Crespo, M.E. Ladygin, A.A. Nozdrin, C. Heß, M. Giorgi, V. Frolov, V.N. Kolosov, F. Stinzing, N.A. Koutchinski, R. Kuhn, D. Kang, K. Königsmann, Christian Schill, A. Padee, O. Nähle, R. Bertini, A.B. Sadovski, R. Hermann, Andrea Ferrero, A. Maggiora, V.A. Dorofeev, L. Dhara, M. Slunecka, B. Badelek, W. Wiślicki, B. Gobbo, A.S. Korentchenko, A.M. Dinkelbach, B. Ketzer, A. Teufel, Oleg V. Ivanov, M. von Hodenberg, F. Kunne, A.A. Popov, N.V. Vlassov, Günter Baum, O.Yu. Shevchenko, V.I. Nikolaenko, R. Garfagnini, M. Finger, V.V. Tchalishev, S. Costa, J.H. Koivuniemi, and S. Panebianco

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Large Hadron Collider, 010308 nuclear & particles physics, media_common.quotation_subject, Structure function, Zero (complex analysis), 01 natural sciences, Asymmetry, Nuclear physics, Deuterium, 0103 physical sciences, COMPASS experiment, 010306 general physics, Spin-½, media_common
Abstract

We present a precise measurement of the deuteron longitudinal spin asymmetry A 1 d and of the deuteron spin-dependent structure function g 1 d at Q 2 1 ( GeV / c ) 2 and 4 × 10 −5 x 2.5 × 10 −2 based on the data collected by the COMPASS experiment at CERN during the years 2002 and 2003. The statistical precision is tenfold better than that of the previous measurement in this region. The measured A 1 d and g 1 d are found to be consistent with zero in the whole range of x.

Published
2007
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23. Gluon polarization in the nucleon from quasi-real photoproduction of high-pT hadron pairs

Author

R. Sulej, S. Neliba, P. Berglund, B. Grube, M.G. Sapozhnikov, H. Schmitt, A. Maggiora, E. Rondio, M. Varanda, A. Zvyagin, W. Kastaun, Colin Bernet, A. Srnka, I. Konorov, M.P. Bussa, A. Korzenev, E.S. Ageev, F. H. Heinsius, S. Gerassimov, J. M. Le Goff, T. Toeda, Marc Wagner, P.D. Eversheim, A. Mielech, S. Ishimoto, Frank Klein, K. Kondo, K. Zaremba, M. Wiesmann, J. Reymann, A.A. Shishkin, V. Duic, Sergey Donskov, O.P. Gavrichtchouk, S. Platchkov, P. Rebourgeard, Y. Bedfer, N. Dedek, L. Sinha, F. Balestra, S. Paul, R. Ziegler, V.N. Kolosov, V.A. Polyakov, N.P. Kravchuk, A.K. Konoplyannikov, J. Zhao, R. Jahn, A. Gorin, V. Diaz, M. Maggiora, R. Ijaduola, N. Takabayashi, R. De Masi, P. Bordalo, J. Bisplinghoff, Massimo Lamanna, Yu. Kisselev, A. Amoroso, Vladimir Peshekhonov, R. Birsa, E.V. Komissarov, Andres Cicuttin, J. Lichtenstadt, Norihiro Doshita, G. Piragino, N. d'Hose, Yu.A. Khokhlov, A. Maximov, G. Reicherz, Josef Pochodzalla, I. Ludwig, Naoaki Horikawa, M. Ostrick, Aram Kotzinian, R. Windmolders, A.A. Nozdrin, J. Nassalski, M. Giorgi, R. Bertini, Andrea Ferrero, Oleg V. Ivanov, R. Joosten, S. Dalla Torre, A. N. Sissakian, J.M. Friedrich, V.D. Samoylenko, Yu. Alexandrov, P. Fauland, Christian Schill, C. Marchand, M.E. Ladygin, V.F. Obraztsov, M. Finger, E. Weise, L. Ferrero, D. Kang, M.L. Colantoni, K. Königsmann, S. Hedicke, A. Colavita, S. Horikawa, R. C. Webb, A.M. Dinkelbach, K. Platzer, V.N. Bytchkov, A.V. Dolgopolov, S. Procureur, K. Kowalik, A.B. Sadovski, L. Cerini, V.I. Tretyak, J. Pretz, A. Grünemaier, G.V. Krivokhizhin, O.A. Grajek, N.A. Koutchinski, M. von Hodenberg, A. Sandacz, F. Karstens, U. Wiedner, S. S. Dasgupta, G.V. Khaustov, L. Schmitt, A. Grasso, M. Stolarski, J. Franz, L. G. Tkatchev, F. Stinzing, Grzegorz Brona, Miroslav Sulc, D. Thers, Anna Zanetti, A. Janata, Franco Bradamante, Gerhard K. Mallot, J. Ehlers, F. Kunne, V.V. Tchalishev, N.I. Jouravlev, S. Costa, E. Burtin, V.F. Konstantinov, W. Meyer, Maria Liz Crespo, A.I. Ioukaev, F. Sozzi, R. Hermann, E. M. Kabuß, Paolo Pagano, V.P. Sugonyaev, Q. Weitzel, A.A. Popov, S. Ramos, J.H. Koivuniemi, K. Rith, F. Hinterberger, P. Schiavon, S. Panebianco, H. Fischer, K. Medved, Alan D. Martin, Z.V. Kroumchtein, W. Eyrich, T. Hasegawa, A. Chapiro, Murray Moinester, T. Schmidt, D. Neyret, M. A. Faessler, Alessandro Bressan, D. von Harrach, C. Ilgner, Yu.V. Mikhailov, S. Trousov, J. Marzec, R. Geyer, A.G. Olshevsky, St. Goertz, O.Yu. Denisov, C. Heß, A. Magnon, L. Dhara, M. Slunecka, Takahiro Iwata, E. Saller, S. Koblitz, M. Sans, B. Gobbo, B. Badelek, J. Marroncle, A. Teufel, Miroslav Virius, K. Kurek, A. Padee, B. Ketzer, D. Peshekhonov, W. Wiślicki, H. D. Pereira, N.V. Vlassov, S. Wirth, C. Quintans, J. Hannappel, Günter Baum, O.Yu. Shevchenko, I.A. Savin, A. Bravar, V.I. Nikolaenko, R. Garfagnini, H.-W. Siebert, I. Manuilov, V. Falaleev, D. Panzieri, T. Liška, M. Fabro, M. Leberig, A.M. Rozhdestvensky, N. V. Khomutov, J. Ball, G.I. Smirnov, Fabrice Gautheron, T. Matsuda, V. Frolov, V.Yu. Alexakhin, W. Dünnweber, G. D. Alexeev, V.A. Dorofeev, A.S. Korentchenko, F. Tessarotto, R. Kuhn, O. Nähle, V. Kalinnikov, and A. Skachkova

Subjects
Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Particle physics, Muon, 010308 nuclear & particles physics, Hadron, Deep inelastic scattering, 01 natural sciences, Helicity, Gluon, Nuclear physics, 0103 physical sciences, COMPASS experiment, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

We present a determination of the gluon polarization Δ G / G in the nucleon, based on the helicity asymmetry of quasi-real photoproduction events, Q 2 1 ( GeV / c ) 2 , with a pair of large transverse-momentum hadrons in the final state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV polarized muon beam scattered on a polarized 6 LiD target. The helicity asymmetry for the selected events is 〈 A ∥ / D 〉 = 0.002 ± 0.019 ( stat ) ± 0.003 ( syst ) . From this value, we obtain in a leading-order QCD analysis Δ G / G = 0.024 ± 0.089 ( stat ) ± 0.057 ( syst ) at x g = 0.095 and μ 2 ≃ 3 ( GeV / c ) 2 .

Published
2006
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24. Anomalous suppression in PbPb interactions at 158 GeV/c per nucleon

Author

R. Haroutunian, G. Landaud, J.Y. Grossiord, F. Bellaiche, L. Ramello, P. Bordalo, A. Devaux, Paolo Giubellino, S. Silva, B. Cheynis, Petar Temnikov, C. Racca, A. Musso, V. Capony, Carlos Lourenco, L. Kluberg, N.S. Topilskaya, Ermanno Vercellin, Corrado Cicalo, Y. Lebornec, C. Quintans, W.L. Prado da Silva, Bruno Alessandro, C. Vale, I. Chevrot, A. Romana, G. Puddu, F. Ohlsson-Malek, João Cruz, O. Drapier, Y.K. Gavrilov, J. Fargeix, A. Marzari-Chiesa, Calin Alexa, Sergio Serci, Marek Idzik, A. Bussiere, M. Bedjidian, L. Luquin, B. Chaurand, Wladyslaw Dabrowski, C. Gerschel, N. De Marco, C. Soave, A. Guichard, M.B. Golubeva, A. Piccotti, J. Castor, D. Jouan, T. Chambon, X. Tarrago, A. B. Kurepin, F.F. Guber, Serban Constantinescu, G. L. Usai, A. De Falco, J. Astruc, P. Saturnini, N. Willis, L. Riccati, Ph. Gorodetzky, A. Masoni, Stefania Beole, G. Dellacasa, J.R. Pizzi, P. Force, S. Ramos, A. Baldit, S. Sartori, M.C. Abreu, T.L. Karavitcheva, B. Espagnon, Massimo Masera, E. Chiavassa, C. Baglin, P. Rato-Mendes, P. Macciotta, P. Guaita, Sanda Dita, François Fleuret, Mauro Gallio, V. Boldea, P. Petiau, P. Sonderegger, L. Gatignon, G. Bonazzola, S. Mourgues, Enrico Scomparin, A. Borhani, and M. Gonin

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Proton, Yield (chemistry), Quark–gluon plasma, Drell–Yan process, Atomic physics, Expected value, Nucleon, Central region, Ion
Abstract

The Drell-Yan and J ψ cross-sections measured in PbPb collisions are compared with the values extrapolated from the results obtained in proton and light ion induced reactions. While the Drell-Yan production exhibits the normal expected behaviour, the yield of J ψ in PbPb interactions is abnormally low, as it lies 9 standard deviations below the expected value. Moreover, the departure from the expected behaviour increases significantly from peripheral to central collisions.

Published
1997
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25. Muon pair and vector meson cross-sections in p-W and SU collisions at 200 GeV/nucleon

Author

R. Ferreira, Carlos Lourenco, A. Baldisseri, J. Fargeix, A. Romana, L. Kluberg, J. Castor, S. Papillon, B. Chaurand, Luis Peralta, C. Gerschel, X. Tarrago, Ph. Gorodetzky, A. Bussière, C. Racca, R. Kossakowski, J.M. Gago, E. Descroix, P. Bordalo, A. Devaux, P. Liaud, T. Chambon, O. Drapier, Rachid Mazini, G. Landaud, J.-R. Pizzi, Didier Contardo, S. Silva, M. Bedjidian, Joao Varela, M.C. Abreu, A. Guichard, B. Espagnon, C. Baglin, R. Haroutunian, P. Force, J.-Y. Grossiord, P. Sonderegger, J. P. Guillaud, S. Ramos, A. Baldit, and D. Jouan

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Muon, Pair production, Transverse momentum, Rapidity, Vector meson, Nucleon, Power law
Abstract

Muon pair production is studied in p-W and SU collisions at 200 GeV per nucleon, as a function of transverse momentum PTμμ. The inclusive ϱ+ω and Φ differential cross-sections dσ dP T are measured in the dimuon decay channel, for PT ≥ 0.6 GeV/c, in the central rapidity region, 3.0≤ y ≤ 4.0. Assuming the power law A-dependence σ = σ0(Abeam·Atarget)α, the study of the integrated cross-sections for p-W and SU collisions leads to αϱ+ω = 1.00±0.02±0.07 and αΦ = 1.23±0.03±0.05, showing clear evidence of Φ enhancement in SU interactions as compared to p-W collisions.

Published
1996
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26. Production of ϱ + ω and Φ in p-W and SU collisions at 200 GeV/nucleon

Author

B. Espagnon, C. Baglin, A. Romana, M.C. Abreu, S. Papillon, G. Landaud, Ph. Gorodetzky, S. Silva, J. Castor, X. Tarrago, A. Guichard, B. Chaurand, Joao Varela, O. Drapier, M. Bedjidian, C. Gerschel, R. Kossakowski, C. Racca, D. Jouan, S. Ramos, A. Baldit, A. Bussière, R. Ferreira, E. Descroix, P. Force, J. Fargeix, P. Sonderegger, J.-R. Pizzi, J.M. Gago, Didier Contardo, Luis Peralta, Carlos Lourenco, L. Kluberg, T. Chambon, Rachid Mazini, A. Baldisseri, P. Liaud, P. Bordalo, A. Devaux, J.-Y. Grossiord, J. P. Guillaud, and R. Haroutunian

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Transverse momentum, Energy density, Transverse mass, Rapidity, Nuclear Experiment, Nucleon
Abstract

The transverse mass differential cross-sections for the ϱ + ω and Φ resonances is obtained, in the central rapidity region, in p - W and S  U interactions at 200 GeV/nucleon. The measured ϱ + ω and Φ temperatures are ∼ 15% higher in S  U as compared to p - W collisions. The ratio of cross-sections times branching ratios into the dimuon channel B Φ σ Φ (B ϱ σ ϱ + B ω σ ω ) is studied as a function of the energy density reached in the collision and of the dimuon transverse momentum. The measured ratio is 2 to 3 times larger in S  U than in p - W collisions and an enhancement is observed in S  U interactions with increasing energy density.

Published
1996
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27. Ψ′ and J/Ψ production in p-W, p-U and S-U interactions at 200 GeV/nucleon

Author

P. Liaud, C. Barriere, P. Force, B. Espagnon, R. Haroutunian, R. Kossakowski, J. Castor, L. Luquin, J.-R. Pizzi, T. Chambon, X. Tarrago, O. Drapier, B. Chaurand, R. Mandry, P. Bordalo, C. Gerschel, S. Ramos, M.C. Abreu, Didier Contardo, A. Devaux, A. Guichard, Carlos Lourenco, L. Kluberg, G. Landaud, M. Bedjidian, C. Baglin, C. Racca, Luis Peralta, P. Sonderegger, Joao Varela, S. Silva, R. Ferreira, Rachid Mazini, J.-Y. Grossiord, J.P. Guillaud, P. Saturnini, F. Ohlsson-Malek, B. Ronceux, A. Bussiere, D. Jouan, D. Lazic, J. Fargeix, E. Descroix, A. Romana, and Ph. Gorodetzky

Subjects
inorganic chemicals, Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, chemistry, digestive, oral, and skin physiology, chemistry.chemical_element, Tungsten, Uranium, Nucleon, respiratory tract diseases
Abstract

Ψ′ and J/Ψ yields are compared in p-W, p-U and S-U interactions at 200 GeV/nucleon. Their ratio decreases from proton-t to sulphur-induced reactions. It also decreases in sulphur-induced reactions from peripheral to central collisions. This result could indicate that the Ψ′ and J/Ψ suppression mechanisms have different origins in p- and S-induced reactions.

Published
1995
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28. φ, ϱ, and ω production in pU, OU and SU reactions at 200 GeV per nucleon

Author

Ph. Gorodetzky, B. Grosdidier, R. Ferreira, R. Kossakowski, G. Landaud, L. Fredj, S. Papillon, Francois Vazeille, A. Romana, R. Cases, Claude Charlot, E. Descroix, P. Bordalo, S. Ramos, M.C. Abreu, A. Baldit, X. Tarrago, F. Staley, A. Devaux, Philippe Busson, S. Silva, J. Castor, A. Guichard, P. Liaud, Luis Peralta, T. Chambon, P. Sonderegger, J. Fargeix, A. Baldisseri, D. Jouan, M. Bedjidian, C. Racca, R. Haroutunian, Joao Varela, A. Bussière, O. Drapier, Didier Contardo, C. Baglin, J.M. Gago, Carlos Lourenco, L. Kluberg, J.-R. Pizzi, X. Felgeyrolles, J.-Y. Grossiord, B. Chaurand, C. Gerschel, J. P. Guillaud, and P. Force

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Muon, 010308 nuclear & particles physics, Nuclear Theory, Hadron, Continuum (design consultancy), 7. Clean energy, 01 natural sciences, Ion, Nuclear physics, Pair production, Yield (chemistry), 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, Low Mass
Abstract

Low mass muon pair production at high P T and low X F studied in pU, OU and SU 200 GeV per nucleon react ions. When energy density or projectile mass are increased, φ production is enhanced as compared with the yield of muon pairs in the mass continuum (1.7 M μμ c 2 ), whereas the production of ω and ϱ, experimentally unresolved, remains approximately constant. This φ enhancement is in agreement with predictions based on quark-gluon plasma formation and, together with the previously reported J/Ψ suppression, puts severe constraints on a purely hadronic description of nucleus-nucleus collisions.

Published
1991
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29. Initial state interactions and J/ψ production in nucleus-nucleus collisions

Author

F. Vazeille, Ph. Gorodetzky, A. Bussiere, C. Baglin, J.-R. Pizzi, Philippe Busson, S. Silva, M. Bedjidian, M.C. Abreu, O. Drapier, J. Fargeix, A. Romana, Joao Varela, L. Fredj, S. Papillon, A. Baldisseri, R. Haroutunian, Didier Contardo, R. Ferreira, J. Castor, Luis Peralta, G. Landaud, J.P. Guillaud, X. Tarrago, B. Chaurand, R. Kossakowski, C. Gerschel, C. Racca, A. Guichard, Carlos Lourenco, L. Kluberg, T. Chambon, J.M. Gago, P. Bordalo, F. Staley, Claude Charlot, A. Devaux, B. Grosdidier, S. Ramos, A. Baldit, P. Force, P. Sonderegger, J.-Y. Grossiord, C. Barriere, P. Liaud, D. Jouan, E. Descroix, Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), ALICE, Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), NA38, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Quantitative Biology::Neurons and Cognition, Meson, 010308 nuclear & particles physics, Hadron, Elementary particle, Quarkonium, 01 natural sciences, Nuclear physics, medicine.anatomical_structure, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, medicine, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus, Boson
Abstract

The mean squared transverse momentum of J/ψ's measured in pCu, pU, OCu, OU and SU collisions at 200 GeV/ nucleon is analyzed in terms of initial state interactions. Taking this effect into account, the mechanism which suppresses the J/ψ production in ion-induced collisions would only have a weak PT dependence.

Published
1991
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30. Transverse momentum of produced in pCu, pU, 16OCu, 16OU and 32SU collisions at 200 GeV per nucleon

Author

R. Haroutunian, X. Tarrago, F. Staley, X. Felgeyrolles, P. Busson, Joao Varela, P. Liaud, O. Drapier, A. Romana, M. Bedjidian, Ph. Gorodetzky, B. Chaurand, D. Jouan, R. Kossakowski, J.-R. Pizzi, C. Gerschel, S. Silva, A. Baldisseri, E. Descroix, J.-Y. Grossiord, Claude Charlot, R.A. Salmeron, M. Alimi, J.M. Gago, C. Baglin, P. Force, L. Fredj, S. Papillon, A. Guichard, M.C. Abreu, Luis Peralta, P. Bordalo, A. Bussière, R. Ferreira, A. Devaux, G. Landaud, B. Grosdidier, Francois Vazeille, R. Cases, C. Racca, S. Ramos, A. Baldit, Carlos Lourenco, L. Kluberg, J. Castor, P. Sonderegger, Didier Contardo, T. Chambon, J. P. Guillaud, and J. Fargeix

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, 0103 physical sciences, Transverse momentum, 010306 general physics, Nucleon, 01 natural sciences
Published
1991
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31. Transverse spin effects in hadron-pair production from semi-inclusive deep inelastic scattering

Author

T. Negrini, M. Chiosso, L. Schmitt, M. Ziembicki, K. Klimaszewski, Andres Cicuttin, G. Reicherz, R. Panknin, N.S. Rossiyskaya, E. Burtin, V.F. Konstantinov, A. Austregesilo, C. Elia, Murray Moinester, S. Dalla Torre, A. Grasso, K. Königsmann, M.G. Sapozhnikov, D.V. Peshekhonov, P.D. Eversheim, H. Fischer, Alan D. Martin, Achim Richter, F. Massmann, G. Pesaro, F. Tessarotto, E. Rondio, O.M. Kouznetsov, S. Ramos, M. Stolarski, C. Heß, I. Gnesi, Johannes Bernhard, A. Guskov, A. Maggiora, S. Neubert, P. Sznajder, Miroslav Sulc, F. Hinterberger, Yu. Kisselev, S. Grabmüller, V.N. Kolosov, M. Bettinelli, Andrea Bressan, E. Perevalova, A. Lehmann, M. Ostrick, Christian Schill, Laura Silva, Aram Kotzinian, R. Windmolders, J. Pochodzalla, R. Sulej, I. Uman, R. Joosten, P. Bordalo, D. Kang, O.P. Gavrichtchouk, L. Sinha, T. Matsuda, V. Duic, P. Jasinski, S.S. Dasgupta, Z.V. Kroumchtein, M. V. Zavertyaev, S. Koblitz, R. Bertini, Andrea Ferrero, J. ter Wolbeek, K. Bicker, C. Marchand, W. Eyrich, G. Piragino, Nour Makke, J. Bieling, J. Barth, L. Lauser, S. Uhl, M. Giorgi, Ch. Höppner, Yu.V. Mikhailov, M. Quaresma, Gerhard K. Mallot, Michal Dziewiecki, O.Yu. Denisov, Takahiro Iwata, A. Vossen, K. Kondo, Y. Bedfer, S. Gerassimov, N. Horikawa, Sergey Donskov, S. Tessaro, K. Schmidt, Norihiro Doshita, A. N. Sissakian, W.-D. Nowak, A. Morreale, P. Schiavon, M. Finger, M. Virius, Yu.A. Khokhlov, R. Gushterski, T. Guthörl, J.M. Friedrich, J. Bisplinghoff, K. Zaremba, S. Huber, Vladimir Nikolaenko, E. Zemlyanichkina, F. Haas, R. Geyer, Soumen Paul, G.I. Smirnov, Fabrice Gautheron, M. A. Faessler, M. Slunecka, W. Wiślicki, B. Gobbo, Yu. Alexandrov, Bakur Parsamyan, C. Quintans, A. Srnka, V.A. Polyakov, A. Korzenev, V.Yu. Alexakhin, N. I. Zhuravlev, A. Zvyagin, R. Birsa, J. Lichtenstadt, L. Wang, G. Sbrizzai, L. Dhara, Federica Sozzi, R. Gazda, S. Das, C. Braun, B. Badelek, S. Schopferer, Franco Bradamante, B. Ketzer, A. Filin, D. Neyret, A. Nagaytsev, F. Balestra, A. Amoroso, K. Schönning, Alexey Antonov, A. Bravar, S. Sosio, A. Mutter, S.-U. Chung, L. G. Tkatchev, S. Takekawa, R. Jahn, Matthias Schott, J. Marzec, G. D. Alexeev, M. Krämer, François Herrmann, W. Dünnweber, C. Franco, A. Mann, N. du Fresne von Hohenesche, T. Schlüter, S. Platchkov, K. Kurek, A.A. Lednev, N.V. Vlassov, Günter Baum, O.Yu. Shevchenko, S. Levorato, E. Rocco, S. Sarkar, F. Nerling, F. Kunne, A. Padee, G.B. Pontecorvo, T. Nagel, J. Pretz, D. Chaberny, R. Garfagnini, C. Adolph, T. Michigami, Oleg V. Ivanov, H. Wollny, Jean-Francois Rajotte, D.I. Ryabchikov, A.S. Nunes, A. Sandacz, D. Panzieri, E. M. Kabuß, I.A. Savin, A.V. Efremov, M.G. Alekseev, I. Konorov, F.H. Heinsius, A.G. Olshevsky, A. Magnon, A. Mielech, S. Ishimoto, Frank Klein, J. Polak, J.H. Koivuniemi, V. Rapatsky, Yu. Ivanshin, S. Goertz, V.D. Samoylenko, B. Grube, D. von Harrach, Maxence Vandenbroucke, G.V. Khaustov, W. Meyer, Maria Liz Crespo, N. dʼHose, C., Adolph, M. G., Alekseev, Alexakhin, V. Y. u., Alexandrov, Y. u., G. D., Alexeev, A., Amoroso, A. A., Antonov, A., Austregesilo, B., Badełek, F., Balestra, J., Barth, G., Baum, Y., Bedfer, J., Bernhard, R., Bertini, M., Bettinelli, K., Bicker, J., Bieling, Birsa, Renato, J., Bisplinghoff, P., Bordalo, Bradamante, Franco, C., Braun, A., Bravar, Bressan, Andrea, E., Burtin, D., Chaberny, M., Chiosso, S. U., Chung, A., Cicuttin, M. L., Crespo, DALLA TORRE, Silvia, S., Da, S. S., Dasgupta, Denisov, O. Y. u., L., Dhara, S. V., Donskov, N., Doshita, Duic, Venicio, W., Dünnweber, M., Dziewiecki, A., Efremov, Elia, Carmine, P. D., Eversheim, W., Eyrich, M., Faessler, A., Ferrero, A., Filin, M., Finger, H., Fischer, C., Franco, N., du Fresne von Hohenesche, J. M., Friedrich, R., Garfagnini, F., Gautheron, O. P., Gavrichtchouk, R., Gazda, S., Gerassimov, R., Geyer, Giorgi, Marcello, I., Gnesi, B., Gobbo, S., Goertz, S., Grabmüller, A., Grasso, B., Grube, R., Gushterski, A., Guskov, T., Guthörl, F., Haa, D., von Harrach, F. H., Heinsiu, F., Herrmann, C., Heß, F., Hinterberger, N., Horikawa, Höppner, C. h., N., Dʼhose, S., Huber, S., Ishimoto, O., Ivanov, Ivanshin, Y. u., T., Iwata, R., Jahn, P., Jasinski, R., Joosten, E., Kabuß, D., Kang, B., Ketzer, G. V., Khaustov, Khokhlov, Y. u. A., Kisselev, Y. u., F., Klein, K., Klimaszewski, S., Koblitz, J. H., Koivuniemi, V. N., Kolosov, K., Kondo, K., Königsmann, I., Konorov, V. F., Konstantinov, A., Korzenev, A. M., Kotzinian, O., Kouznetsov, M., Krämer, Z. V., Kroumchtein, F., Kunne, K., Kurek, L., Lauser, A. A., Lednev, A., Lehmann, Levorato, Stefano, J., Lichtenstadt, A., Maggiora, A., Magnon, Makke, Nour, G. K., Mallot, A., Mann, C., Marchand, Martin, Anna, J., Marzec, F., Massmann, T., Matsuda, W., Meyer, T., Michigami, A., Mielech, Mikhailov, Y. u. V., M. A., Moinester, A., Morreale, A., Mutter, A., Nagaytsev, T., Nagel, T., Negrini, F., Nerling, S., Neubert, D., Neyret, V. I., Nikolaenko, W. D., Nowak, A. S., Nune, A. G., Olshevsky, M., Ostrick, A., Padee, R., Panknin, D., Panzieri, B., Parsamyan, S., Paul, E., Perevalova, Pesaro, Giulia, D. V., Peshekhonov, G., Piragino, S., Platchkov, J., Pochodzalla, J., Polak, V. A., Polyakov, G., Pontecorvo, J., Pretz, M., Quaresma, C., Quintan, J. F., Rajotte, S., Ramo, V., Rapatsky, G., Reicherz, A., Richter, Rocco, Elena, E., Rondio, N. S., Rossiyskaya, D. I., Ryabchikov, V. D., Samoylenko, A., Sandacz, M. G., Sapozhnikov, S., Sarkar, I. A., Savin, Sbrizzai, Giulio, Schiavon, Paolo, C., Schill, T., Schlüter, K., Schmidt, L., Schmitt, K., Schönning, S., Schopferer, M., Schott, Shevchenko, O. Y. u., L., Silva, L., Sinha, A. N., Sissakian, M., Slunecka, G. I., Smirnov, S., Sosio, Sozzi, Federica, A., Srnka, M., Stolarski, M., Sulc, R., Sulej, P., Sznajder, S., Takekawa, J., Ter Wolbeek, Tessaro, Susanna, F., Tessarotto, L. G., Tkatchev, S., Uhl, I., Uman, M., Vandenbroucke, M., Viriu, N. V., Vlassov, A., Vossen, L., Wang, R., Windmolder, W., Wiślicki, H., Wollny, K., Zaremba, M., Zavertyaev, E., Zemlyanichkina, M., Ziembicki, N., Zhuravlev, and A., Zvyagin

Subjects
Nuclear and High Energy Physics, Particle physics, COMPASS, SIDIS, two hadron azimuthal asymmetries, transversity, Hadron, Nuclear Theory, FOS: Physical sciences, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, 010306 general physics, Nuclear Experiment, Physics, Large Hadron Collider, Muon, Spectrometer, ta114, 010308 nuclear & particles physics, Scattering, two hadron azimuthal asymmetrie, High Energy Physics::Phenomenology, Deep inelastic scattering, Pair production, Distribution function, High Energy Physics::Experiment, Particle Physics - Experiment
Abstract

First measurements of azimuthal asymmetries in hadron-pair production in deep-inelastic scattering of muons on transversely polarised ^6LiD (deuteron) and NH_3 (proton) targets are presented. The data were taken in the years 2002-2004 and 2007 with the COMPASS spectrometer using a muon beam of 160 GeV/c at the CERN SPS. The asymmetries provide access to the transversity distribution functions, without involving the Collins effect as in single hadron production. The sizeable asymmetries measured on the NH_ target indicate non-vanishing u-quark transversity and two-hadron interference fragmentation functions. The small asymmetries measured on the ^6LiD target can be interpreted as indication for a cancellation of u- and d-quark transversities., Comment: 13 pages, 4 figures, updated to the published version

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32. Corrigendum to 'Odd and even partial waves of ηπ− and η′π− in π−p → η(′)π−p at 191 GeV/c' [Phys. Lett. B 740 (2015) 303–311]

Author

C. Adolph, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Austregesilo, B. Badełek, F. Balestra, J. Barth, G. Baum, R. Beck, Y. Bedfer, A. Berlin, J. Bernhard, K. Bicker, E.R. Bielert, J. Bieling, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, E. Burtin, L. Capozza, M. Chiosso, S.U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, C. Elia, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, R. Geyer, I. Gnesi, B. Gobbo, S. Goertz, M. Gorzellik, S. Grabmüller, A. Grasso, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. von Harrach, D. Hahne, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, Ch. Höppner, N. Horikawa, N. d'Hose, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, P. Jasinski, P. Jörg, R. Joosten, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, M. Krämer, Z.V. Kroumchtein, N. Kuchinski, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, A. Maggiora, A. Magnon, N. Makke, G.K. Mallot, C. Marchand, A. Martin, J. Marzec, J. Matousek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, M. Mikhasenko, Y. Miyachi, A. Nagaytsev, T. Nagel, F. Nerling, S. Neubert, D. Neyret, J. Novy, W.-D. Nowak, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, R. Panknin, D. Panzieri, B. Parsamyan, S. Paul, D.V. Peshekhonov, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, E. Rocco, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rychter, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, C. Schill, T. Schlüter, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, M. Schott, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, S. Sosio, F. Sozzi, A. Srnka, L. Steiger, M. Stolarski, M. Sulc, R. Sulej, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, J. ter Wolbeek, S. Tessaro, F. Tessarotto, F. Thibaud, S. Uhl, I. Uman, M. Virius, L. Wang, T. Weisrock, M. Wilfert, R. Windmolders, H. Wollny, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink

Subjects
Physics, QC1-999
Abstract

In Fig. 5 on p. 311 of our Phys. Lett. B 740 (2015) 303 an adjustment by 180∘ is required for the phases with respect to the L=2,M=1 wave, of the following waves: L=1,3,5 with M=1, and L=2 with M=2. After this correction (Fig. 5 (corrected) below), the extracted partial waves describe the angular distribution of the η(′) in the Gottfried-Jackson (GJ) frame, using Eq. (4) with implicit Condon-Shortley phase convention. The other results of our paper are not affected. The right-handed GJ coordinate system was defined by the z-axis pointing in the direction of the beam in the η(′)π− center-of-mass system and the y-axis pointing in the direction of precoilGJ×pbeamGJ.

Published
2020
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33. Measurement of the cross section for hard exclusive π0 muoproduction on the proton

Author

M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, M. Jandek, V. Jary, R. Joosten, P. Jörg, K. Juraskova, E. Kabuß, F. Kaspar, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo Horikawa, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A. Kveton, S. Levorato, Y.-S. Lian, J. Lichtenstadt, P.-J. Lin, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, B. Marianski, A. Martin, J. Marzec, J. Matoušek, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, C. Naim, A. Nagaytsev, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, M. Pešková, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, D.I. Ryabchikov, A. Rybnikov, A. Rychter, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, H. Schmieden, A. Selyunin, L. Silva, L. Sinha, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, B.M. Veit, J. Veloso, A. Vidon, M. Virius, M. Wagner, S. Wallner, M. Wilfert, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, Y. Zhao, and M. Ziembicki

Subjects
Quantum chromodynamics, Muoproduction, Hard exclusive meson production, Generalised Parton Distributions, COMPASS, Physics, QC1-999
Abstract

We report on a measurement of hard exclusive π0 muoproduction on the proton by COMPASS using 160GeV/c polarised μ+ and μ− beams of the CERN SPS impinging on a liquid hydrogen target. From the average of the measured μ+ and μ− cross sections, the virtual-photon proton cross section is determined as a function of the squared four-momentum transfer between initial and final proton in the range 0.08(GeV/c)2

Published
2020
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34. K− over K+ multiplicity ratio for kaons produced in DIS with a large fraction of the virtual-photon energy

Author

R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, A. Bressan, M. Büchele, V.E. Burtsev, L. Capozza, W.-C. Chang, C. Chatterjee, M. Chiosso, A.G. Chumakov, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, W. Dünnweber, R.R. Dusaev, M. Dziewiecki, A. Efremov, P.D. Eversheim, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, I. Gnesi, M. Gorzellik, A. Grasso, A. Gridin, M. Grosse Perdekamp, B. Grube, A. Guskov, D. Hahne, G. Hamar, D. von Harrach, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, Z. Kral, M. Krämer, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, I.I. Kuznetsov, A. Kveton, A.A. Lednev, E.A. Levchenko, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, V.E. Lyubovitskij, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, S.A. Mamon, C. Marchand, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Moretti, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, G. Pesaro, M. Pešek, M. Pešková, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, H. Schmieden, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, F. Sozzi, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, M. Tasevsky, S. Tessaro, F. Tessarotto, A. Thiel, J. Tomsa, F. Tosello, V. Tskhay, S. Uhl, B.I. Vasilishin, A. Vauth, B.M. Veit, J. Veloso, A. Vidon, M. Virius, S. Wallner, M. Wilfert, R. Windmolders, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, and M. Ziembicki

Subjects
Physics, QC1-999
Abstract

The K− over K+ multiplicity ratio is measured in deep-inelastic scattering, for the first time for kaons carrying a large fraction z of the virtual-photon energy. The data were obtained by the COMPASS collaboration using a 160 GeV muon beam and an isoscalar 6LiD target. The regime of deep-inelastic scattering is ensured by requiring Q2>1(GeV/c)2 for the photon virtuality and W>5GeV/c2 for the invariant mass of the produced hadronic system. Kaons are identified in the momentum range from 12 GeV/c to 40 GeV/c, thereby restricting the range in Bjorken-x to 0.010.75. For very large values of z, i.e. z>0.8, we observe the kaon multiplicity ratio to fall below the lower limits expected from calculations based on leading and next-to-leading order perturbative quantum chromodynamics. Also, the kaon multiplicity ratio shows a strong dependence on the missing mass of the single-kaon production process. This suggests that within the perturbative quantum chromodynamics formalism an additional correction may be required, which takes into account the phase space available for hadronisation.

Published
2018
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35. Σ0 production in proton nucleus collisions near threshold

Author

J. Adamczewski-Musch, G. Agakishiev, O. Arnold, E.T. Atomssa, C. Behnke, J.C. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Böhmer, P. Bordalo, S. Chernenko, C. Deveaux, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Fröhlich, T. Galatyuk, J.A. Garzón, R. Gernhäuser, K. Gill, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, S. Hlavac, C. Höhne, R. Holzmann, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kämpfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, B.W. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krása, E. Krebs, H. Kuc, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, S. Maurus, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Müntz, R. Münzer, L. Naumann, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, V. Petousis, J. Pietraszko, W. Przygoda, S. Ramos, B. Ramstein, L. Rehnisch, A. Reshetin, A. Rost, A. Rustamov, A. Sadovsky, P. Salabura, T. Scheib, K. Schmidt-Sommerfeld, H. Schuldes, P. Sellheim, J. Siebenson, L. Silva, Yu.G. Sobolev, S. Spataro, H. Ströbele, J. Stroth, P. Strzempek, C. Sturm, O. Svoboda, A. Tarantola, K. Teilab, P. Tlusty, M. Traxler, H. Tsertos, T. Vasiliev, V. Wagner, C. Wendisch, J. Wirth, J. Wüstenfeld, Y. Zanevsky, and P. Zumbruch

Subjects
Physics, QC1-999
Abstract

The production of Σ0 baryons in the nuclear reaction p (3.5 GeV) + Nb (corresponding to sNN=3.18 GeV) is studied with the detector set-up HADES at GSI, Darmstadt. Σ0s were identified via the decay Σ0→Λγ with subsequent decays Λ→pπ− in coincidence with a e+e− pair from either external (γ→e+e−) or internal (Dalitz decay γ⁎→e+e−) gamma conversions. The differential Σ0 cross section integrated over the detector acceptance, i.e. the rapidity interval 0.5

Published
2018
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36. First measurement of the Sivers asymmetry for gluons using SIDIS data

Author

C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, A. Antoshkin, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N.S. Rogacheva, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, A. Vauth, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink

Subjects
Deep inelastic scattering, Gluon, Sivers, TMD, PDF, Physics, QC1-999
Abstract

The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. For quarks, it was studied in previous measurements of the azimuthal asymmetry of hadrons produced in semi-inclusive deep inelastic scattering of leptons off transversely polarised nucleon targets, and it was found to be non-zero. In this letter the evaluation of the Sivers asymmetry for gluons is presented. The contribution of the photon–gluon fusion subprocess is enhanced by requiring two high transverse-momentum hadrons. The analysis method is based on a Monte Carlo simulation that includes three hard processes: photon–gluon fusion, QCD Compton scattering and the leading-order virtual-photon absorption process. The Sivers asymmetries of the three processes are simultaneously extracted using the LEPTO event generator and a neural network approach. The method is applied to samples of events containing at least two hadrons with large transverse momentum from the COMPASS data taken with a 160 GeV/c muon beam scattered off transversely polarised deuterons and protons. With a significance of about two standard deviations, a negative value is obtained for the gluon Sivers asymmetry. The result of a similar analysis for a Collins-like asymmetry for gluons is consistent with zero.

Published
2017
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37. Final COMPASS results on the deuteron spin-dependent structure function g1d and the Bjorken sum rule

Author

C. Adolph, M. Aghasyan, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, Ch. Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F.H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, A. Vauth, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, R. Windmolders, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink

Subjects
COMPASS, Deep inelastic scattering, Spin, Structure function, Parton helicity distributions, Physics, QC1-999
Abstract

Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6LiD target. The data were taken at 160 GeV beam energy and the results are shown for the kinematic range 1(GeV/c)24GeV/c2 in the mass of the hadronic final state. The deuteron double-spin asymmetry A1d and the deuteron longitudinal-spin structure function g1d are presented in bins of x and Q2. Towards lowest accessible values of x, g1d decreases and becomes consistent with zero within uncertainties. The presented final g1d values together with the recently published final g1p values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g1 world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge a0, which is identified in the MS‾ renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a0(Q2=3(GeV/c)2)=0.32±0.02stat±0.04syst±0.05evol. Together with the recent results on the proton spin structure function g1p, the results on g1d constitute the COMPASS legacy on the measurements of g1 through inclusive spin-dependent deep inelastic scattering.

Published
2017
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38. Multiplicities of charged pions and charged hadrons from deep-inelastic scattering of muons off an isoscalar target

Author

C. Adolph, M. Aghasyan, R. Akhunzyanov, G.D. Alexeev, M.G. Alexeev, A. Amoroso, V. Andrieux, N.V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, L. Capozza, W.-C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, D. von Harrach, R. Hashimoto, F.H. Heinsius, R. Heitz, F. Herrmann, F. Hinterberger, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O.M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, R. Kuhn, Y. Kulinich, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y.-S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, C. Marchand, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G.V. Meshcheryakov, M. Meyer, W. Meyer, T. Michigami, Yu.V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, P. Montuenga, A. Nagaytsev, F. Nerling, D. Neyret, V.I. Nikolaenko, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, E. Seder, A. Selyunin, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, F. Sozzi, A. Srnka, D. Steffen, M. Stolarski, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, J. Vondra, T. Weisrock, M. Wilfert, R. Windmolders, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, and A. Zink

Subjects
Deep inelastic scattering, Pion multiplicities, Fragmentation functions, Physics, QC1-999
Abstract

Multiplicities of charged pions and charged hadrons produced in deep-inelastic scattering were measured in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y and the relative hadron energy z. Data were obtained by the COMPASS Collaboration using a 160GeV muon beam and an isoscalar target (6LiD). They cover the kinematic domain in the photon virtuality Q2>1(GeV/c)2, 0.004

Published
2017
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39. Longitudinal double spin asymmetries in single hadron quasi-real photoproduction at high pT

Author

C. Adolph, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, W. Augustyniak, A. Austregesilo, C.D.R. Azevedo, B. Badełek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E.R. Bielert, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, E. Burtin, W.-C. Chang, M. Chiosso, I. Choi, S.-U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, L. Dhara, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, D. von Harrach, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, N. Horikawa, N. d'Hose, C.-Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, R. Joosten, P. Jörg, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z.V. Kroumchtein, N. Kuchinski, R. Kuhn, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, N. Makins, N. Makke, G.K. Mallot, C. Marchand, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, Y. Miyachi, P. Montuenga, A. Nagaytsev, F. Nerling, D. Neyret, V.I. Nikolaenko, J. Nový, W.-D. Nowak, G. Nukazuka, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, J.-C. Peng, F. Pereira, M. Pešek, D.V. Peshekhonov, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rychter, V.D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, A. Selyunin, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, F. Sozzi, A. Srnka, M. Stolarski, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, S. Tessaro, F. Tessarotto, F. Thibaud, F. Tosello, V. Tskhay, S. Uhl, J. Veloso, M. Virius, T. Weisrock, M. Wilfert, J. ter Wolbeek, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink

Subjects
COMPASS, Deep inelastic scattering, Double spin asymmetry, High pT, ΔG, Physics, QC1-999
Abstract

We measured the longitudinal double spin asymmetries ALL for single hadron muoproduction off protons and deuterons at photon virtuality Q2

Published
2016
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40. Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised protons

Author

C. Adolph, R. Akhunzyanov, M.G. Alexeev, G.D. Alexeev, A. Amoroso, V. Andrieux, V. Anosov, A. Austregesilo, B. Badełek, F. Balestra, J. Barth, G. Baum, R. Beck, Y. Bedfer, A. Berlin, J. Bernhard, K. Bicker, E.R. Bielert, J. Bieling, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, E. Burtin, L. Capozza, M. Chiosso, S.U. Chung, A. Cicuttin, M.L. Crespo, Q. Curiel, S. Dalla Torre, S.S. Dasgupta, S. Dasgupta, O.Yu. Denisov, S.V. Donskov, N. Doshita, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, C. Elia, P.D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, Jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J.M. Friedrich, V. Frolov, F. Gautheron, O.P. Gavrichtchouk, S. Gerassimov, R. Geyer, I. Gnesi, B. Gobbo, S. Goertz, M. Gorzellik, S. Grabmüller, A. Grasso, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. von Harrach, D. Hahne, R. Hashimoto, F.H. Heinsius, F. Herrmann, F. Hinterberger, Ch. Höppner, N. Horikawa, N. d'Hose, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, P. Jasinski, P. Jörg, R. Joosten, E. Kabuß, B. Ketzer, G.V. Khaustov, Yu.A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski, J.H. Koivuniemi, V.N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V.F. Konstantinov, A.M. Kotzinian, O. Kouznetsov, M. Krämer, Z.V. Kroumchtein, N. Kuchinski, F. Kunne, K. Kurek, R.P. Kurjata, A.A. Lednev, A. Lehmann, M. Levillain, S. Levorato, J. Lichtenstadt, A. Maggiora, A. Magnon, N. Makke, G.K. Mallot, C. Marchand, A. Martin, J. Marzec, J. Matousek, H. Matsuda, T. Matsuda, G. Meshcheryakov, W. Meyer, T. Michigami, Yu.V. Mikhailov, Y. Miyachi, A. Nagaytsev, T. Nagel, F. Nerling, S. Neubert, D. Neyret, J. Novy, W.-D. Nowak, A.S. Nunes, A.G. Olshevsky, I. Orlov, M. Ostrick, R. Panknin, D. Panzieri, B. Parsamyan, S. Paul, G. Pesaro, D.V. Peshekhonov, S. Platchkov, J. Pochodzalla, V.A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, E. Rocco, N.S. Rossiyskaya, D.I. Ryabchikov, A. Rychter, V.D. Samoylenko, A. Sandacz, S. Sarkar, I.A. Savin, G. Sbrizzai, P. Schiavon, C. Schill, T. Schlüter, K. Schmidt, H. Schmieden, K. Schönning, S. Schopferer, M. Schott, O.Yu. Shevchenko, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, S. Sosio, F. Sozzi, A. Srnka, L. Steiger, M. Stolarski, M. Sulc, R. Sulej, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, J. ter Wolbeek, S. Tessaro, F. Tessarotto, F. Thibaud, S. Uhl, I. Uman, M. Virius, L. Wang, T. Weisrock, M. Wilfert, R. Windmolders, H. Wollny, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, and A. Zink

Subjects
Physics, QC1-999
Abstract

Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise.

Published
2015
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