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7. Evidence of random distribution of carbon impurities in oxygen sites of zinc oxide

Author

Seif O. Cholakh, A.V. Efremov, Lin Cui, Ernst Z. Kurmaev, M. A. Korotin, D. A. Zatsepin, and N. V. Gavrilov

Subjects
010302 applied physics, Materials science, chemistry.chemical_element, 02 engineering and technology, Zinc, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Molecular physics, Oxygen, Spectral line, Electronic, Optical and Magnetic Materials, Condensed Matter::Materials Science, Matrix (mathematics), chemistry, Impurity, Condensed Matter::Superconductivity, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Supercell (crystal), Coherent potential approximation, Condensed Matter::Strongly Correlated Electrons, Density functional theory, Electrical and Electronic Engineering, 0210 nano-technology
Abstract

A density functional study of substitutional carbon impurities in ZnO-host matrix with 6.25 at. % was performed applying both the supercell method and the coherent potential approximation. The first of these methods assumes the spatially ordered arrangement of carbon impurities in oxygen sites, whereas the second one simulates the spatially disordered impurity substitution of oxygen sublattice. In conjunction with a theoretical part, the X-ray photoelectron spectra of pure and C-doped zinc oxide were measured. The mapping of the valence band of the carbon-loaded ZnO allows establishing the appearance of impurity C 2p electronic states on the valence band top. The experimental energy position of these impurity C 2p states is theoretically reproducing essentially better by the assumption about random distribution of carbon impurities in oxygen sublattice.

Published
2018
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8. Longitudinal double-spin asymmetry A1p and spin-dependent structure function g1p of the proton at small values of x and Q2

Author

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

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

We present a precise measurement of the proton longitudinal double-spin asymmetry A 1 p and the proton spin-dependent structure function g 1 p at photon virtualities 0.006 ( GeV / c ) 2 Q 2 1 ( GeV / c ) 2 in the Bjorken x range of 4 × 10 − 5 x 4 × 10 − 2 . The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of 160 GeV and 200 GeV . The statistical precision is more than tenfold better than that of the previous measurement in this region. In the whole range of x , the measured values of A 1 p and g 1 p are found to be positive. It is for the first time that spin effects are found at such low values of x .

Published
2018
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9. The ratio R = dσ/dσ in heavy-quark pair leptoproduction as a probe of linearly polarized gluons in unpolarized proton

Author

A.V. Efremov, Oleg Teryaev, and N. Ya. Ivanov

Subjects
Quantum chromodynamics, Quark, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Linear polarization, High Energy Physics::Lattice, Nuclear Theory, High Energy Physics::Phenomenology, Virtual particle, Polarization (waves), 01 natural sciences, lcsh:QC1-999, Gluon, Nuclear physics, Transverse plane, 0103 physical sciences, Proton spin crisis, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, lcsh:Physics
Abstract

We study the Callan–Gross ratio R=dσL/dσT in heavy-quark pair leptoproduction, lN→l′QQ¯X, as a probe of linearly polarized gluons inside unpolarized proton, where dσT (dσL) is the differential cross section of the γ⁎N→QQ¯X process initiated by a transverse (longitudinal) virtual photon. Note first that the maximal value for the quantity R allowed by the photon-gluon fusion with unpolarized gluons is large, about 2. We calculate the contribution of the transverse-momentum dependent gluonic counterpart of the Boer–Mulders function, h1⊥g, describing the linear polarization of gluons inside unpolarized proton. Our analysis shows that the maximum value of the ratio R depends strongly on the gluon polarization; it varies from 0 to Q24m2 depending on h1⊥g. We conclude that the Callan–Gross ratio in heavy-quark pair leptoproduction is predicted to be large and very sensitive to the contribution of linearly polarized gluons. For this reason, future measurements of the longitudinal and transverse components of the charm and bottom production cross sections at the proposed EIC and LHeC colliders seem to be very promising for determination of the linear polarization of gluons inside unpolarized proton.

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

Author

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

Subjects
M012M3, 11.80.Et, COMPASS, 01 natural sciences, High Energy Physics - Experiment, UNITARITY, Subatomär fysik, Pomeron, Compass, excited state, Subatomic Physics, Nuclear and high energy physics, peripheral photoproduction, physics, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], COMPASS experiment, EXCHANGE, a2(1320), Nuclear Experiment, a2(1700), Quantum chromodynamics, Physics, Unitarity, PP INTERACTIONS, hep-ph, amplitude analysis, MESONS, lcsh:QC1-999, analytic properties, High Energy Physics - Phenomenology, Amplitude, S-matrix, Particle Physics - Experiment, AMPLITUDE ANALYSIS, Nuclear and High Energy Physics, Particle physics, Meson, CONNECTION, PHYSICS, 14.40.Be, [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], pomeron, 0103 physical sciences, ddc:530, Tensor, 010306 general physics, M012W3, Particle Physics - Phenomenology, POMERON, hep-ex, 010308 nuclear & particles physics, M162M, 11.55.Bq, 11.55.Fv, meson resonance, M162W, Physics and Astronomy, 450 GEV/C, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], [ PHYS.HPHE ] Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, MATRIX, lcsh:Physics
Abstract

We present a new amplitude analysis of the $\eta\pi$ $D$-wave in $\pi^- p\to \eta\pi^- p$ 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 $a_2(1320)$ and the excited $a_2^\prime(1700)$, and perform a comprehensive analysis of their pole positions. For the mass and width of the $a_2$ we find $M=(1307 \pm 1 \pm 6)$~MeV and $\Gamma=(112 \pm 1 \pm 8)$~MeV, and for the excited state $a_2^\prime$ we obtain $M=(1720 \pm 10 \pm 60)$~MeV and $\Gamma=(280\pm 10 \pm 70)$~MeV, respectively., Comment: 15 pages, 6 figures

Published
2018
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11. XPS spectra, electronic structure, and magnetic properties of RFe5Al7 intermetallics

Author

Denis Gorbunov, Ernst Z. Kurmaev, N. V. Mushnikov, Ivan S. Zhidkov, M. A. Korotin, Seif O. Cholakh, Larisa D. Finkelstein, A.V. Efremov, Alexander V. Andreev, and Andrey I. Kukharenko

Subjects
Materials science, Valence (chemistry), Magnetic moment, Mechanical Engineering, Metals and Alloys, Analytical chemistry, 02 engineering and technology, Electronic structure, 021001 nanoscience & nanotechnology, 01 natural sciences, Magnetization, Crystallography, Mechanics of Materials, Ferrimagnetism, 0103 physical sciences, Materials Chemistry, Curie temperature, Multiplicity (chemistry), 010306 general physics, 0210 nano-technology, Ground state
Abstract

The results of X-ray photoelectron spectroscopy measurements (core levels and valence bands) of RFe5Al7 (R = Lu, Tm, Er, Ho, Dy, Tb, Gd) single crystals are presented in comparison with the results of bulk magnetization studies and electronic structure calculations. It is shown that the increase of the Curie temperature in RFe5Al7 from Tm to Gd is associated with an increase of the indirect R 4f – Fe 3d exchange interaction at the expense of the multiplicity 2S + 1 (statistical weight) in the ground state 2S+1LJ of R3+ ions. The nonmonotonic behavior of the ferrimagnetic compensation temperature, Tcomp, as well as the values of the spontaneous magnetic moment, Ms, and formation energy, Eform, of the 4fn levels in R metals in a series from ErFe5Al7 to GdFe5Al7 are explained by the difference in the quantum numbers L, J and S of the ground state of R3+ ions, leading to a maximum value of Tcomp, Ms and Eform for the Dy-containing compound. The electronic structure of Gd/LuFe5Al7 is calculated using the GGA+U approach, on the basis of which the physical mechanism and relative strength of the interatomic R-Fe and Al-Fe interactions are considered, and also the difference in the magnetic moments of iron atoms in different structural positions is explained.

Published
2018
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12. Structure of the nucleon at leading and subleading twist in the covariant parton model

Author

Petr Zavada, S. Bastami, Oleg Teryaev, A.V. Efremov, and Peter Schweitzer

Subjects
Physics, Quark, Particle physics, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Structure (category theory), FOS: Physical sciences, Parton, 16. Peace & justice, 01 natural sciences, High Energy Physics - Phenomenology, Distribution function, High Energy Physics - Phenomenology (hep-ph), Consistency (statistics), 0103 physical sciences, Covariant transformation, Twist, 010306 general physics, Nucleon
Abstract

The covariant parton model is generalized to describe quark correlators in a systematic way. Previous results are reproduced for the T-even leading-twist transverse momentum dependent parton distribution functions (TMDs), and for the first time all T-even twist-3 TMDs are evaluated in this model. We apply the approach to evaluate the fully unintegrated quark correlator which allows us to understand the model-specific relations between different TMDs. We verify the consistency of the approach, present numerical results and compare to available TMD parametrizations., Comment: 20 pages, 6 figures

Published
2020
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13. 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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14. Resonance production and ππ S -wave in π−+p→π−π−π++precoil at 190 GeV/c

Author

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

Subjects
Quantum chromodynamics, Physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, 01 natural sciences, Nuclear physics, Amplitude, Recoil, 0103 physical sciences, S-wave, Pi, Isobar, 010306 general physics
Abstract

The COMPASS collaboration has collected the currently largest data set on diffractively produced pi(-) pi(-) pi(+) final states using a negative pion beam of 190 GeV/c momentum impinging on a stationary proton target. This data set allows for a systematic partial-wave analysis in 100 bins of three-pion mass, 0.5 < m(3 pi) < 2.5 GeV/c(2), and in 11 bins of the reduced four-momentum transfer squared, 0.1 < t' < 1.0 (GeV/c)(2). This two-dimensional analysis offers sensitivity to genuine one-step resonance production, i.e. the production of a state followed by its decay, as well as to more complex dynamical effects in nonresonant 3 pi production. In this paper, we present detailed studies on selected 3p partial waves with J(PC) = 0(-+) ,1(++) ,2(-+) ,2(++) ,and 4(++). In these waves, we observe the well-known groundstate mesons as well as a new narrow axial-vector meson a(1)(1420) decaying into f(0) (980)pi. In addition, we present the results of a novel method to extract the amplitude of the pi(-)pi(+) subsystem with I(G)J(PC) = 0(+)0(++) in various partial waves from the pi(-)pi(-)pi(+) data. Evidence is found for correlation of the f (0)(980) and f(0)(1500) appearing as intermediate pi(-)pi(+) isobars in the decay of the known pi(1800) and pi(2)(1880).

Published
2017
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15. How to measure the linear polarization of gluons in unpolarized proton using the heavy-quark pair leptoproduction

Author

Oleg Teryaev, A.V. Efremov, and N. Ya. Ivanov

Subjects
Quark, Nuclear and High Energy Physics, Particle physics, High Energy Physics::Lattice, Nuclear Theory, FOS: Physical sciences, 01 natural sciences, Computer Science::Digital Libraries, High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, Proton spin crisis, 010306 general physics, Nuclear Experiment, Quantum chromodynamics, Physics, 010308 nuclear & particles physics, Linear polarization, Scattering, High Energy Physics::Phenomenology, Polarization (waves), lcsh:QC1-999, Gluon, High Energy Physics - Phenomenology, High Energy Physics::Experiment, lcsh:Physics, Lepton
Abstract

We study the azimuthal $\cos \varphi$ and $\cos 2\varphi$ asymmetries in heavy-quark pair leptoproduction, $lN\rightarrow l^{\prime}Q\bar{Q}X$, as probes of linearly polarized gluons inside unpolarized proton, where the azimuth $\varphi$ is the angle between the lepton scattering plane $(l,l^{\prime})$ and the heavy quark production plane $(N,Q)$. First, we determine the maximal values for the $\cos \varphi$ and $\cos 2\varphi$ asymmetries allowed by the photon-gluon fusion with unpolarized gluons; these predictions are large, $(\sqrt{3}-1)/2$ and $1/3$, respectively. Then we calculate the contribution of the transverse-momentum dependent gluonic counterpart of the Boer-Mulders function, $h_{1}^{\perp g}$, describing the linear polarization of gluons inside unpolarized proton. Our analysis shows that the maximum values of the azimuthal distributions depend strongly on the gluon polarization; they vary from 0 to 1 depending on $h_{1}^{\perp g}$. We conclude that the azimuthal $\cos \varphi$ and $\cos 2\varphi$ asymmetries in heavy-quark pair leptoproduction are predicted to be large and very sensitive to the contribution of linearly polarized gluons. For this reason, future measurements of the azimuthal distributions in charm and bottom production at the proposed EIC and LHeC colliders seem to be very promising for determination of the linear polarization of gluons inside unpolarized proton., Comment: 10 pages, 6 figures, journal version

Published
2017
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16. 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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17. Exclusive muoproduction on transversely polarised protons and deuterons

Author

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

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Angular momentum, Muon, Meson, 010308 nuclear & particles physics, media_common.quotation_subject, Nuclear Theory, Parton, 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, media_common, Spin-½
Abstract

The transverse target spin azimuthal asymmetry A(UT)(sin(phi-phi s)) in hard exclusive production of rho(0) mesons was measured at COMPASS by scattering 160 GeV/c muons off transversely polarised protons and deuterons. The measured asymmetry is sensitive to the nucleon helicity-flip generalised parton distributions E-q, which are related to the orbital angular momentum of quarks in the nucleon. The Q(2), x-B-j and p(T)(2) dependence of A(UT)(sin(phi-phi s)) is presented in a wide kinematic range: 1 (GeV/c)(2) < Q(2) < 10 (GeV/c)(2), 0.003 < xB(j) < 0.3 and 0.05 (GeV/c)(2) < p(T)(2) < 0.5 (GeV/c)(2) for protons or 0.10 (GeV/c)(2) < p(T)(2) < 0.5 (GeV/c)(2) for deuterons. Results for deuterons are obtained for the first time. The measured asymmetry is small in the whole kinematic range for both protons and deuterons, which is consistent with the theoretical interpretation that contributions from GPDs E-u and E-d approximately cancel. (C) 2012 Elsevier B.V. All rights reserved.

Published
2012
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18. Electronic structure of titanium monoxide with randomly distributed vacancies

Author

Alexander Moewes, Ernst Z. Kurmaev, A.V. Efremov, and M. A. Korotin

Subjects
Materials science, Physics and Astronomy (miscellaneous), Solid-state physics, chemistry.chemical_element, Monoxide, Electronic structure, Oxygen, Molecular physics, Spectral line, Condensed Matter::Materials Science, chemistry, Phase (matter), Physics::Atomic and Molecular Clusters, Coherent potential approximation, Physics::Chemical Physics, Titanium
Abstract

The electronic structure of titanium monoxide TiOy (0.810 ≤ y ≤ 1.262) in the high-temperature cubic phase with vacancies randomly distributed over the titanium and oxygen sublattices is calculated in the coherent potential approximation. The changes in the electronic spectra with the concentration of vacancies are retraced. The calculated spectra are compared to the available experimental data.

Published
2012
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19. 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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20. Sivers effect in semi-inclusive DIS and in the Drell–Yan process

Author

Klaus Goeke, A.V. Efremov, Andreas Metz, S. Menzel, and Peter Schweitzer

Subjects
Quantum chromodynamics, Physics, Particle physics, Nuclear and High Energy Physics, media_common.quotation_subject, High Energy Physics::Phenomenology, Drell–Yan process, FOS: Physical sciences, Parton, Inelastic scattering, Asymmetry, Universality (dynamical systems), Nuclear physics, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Factorization, Compass, High Energy Physics::Experiment, media_common
Abstract

The Sivers parton distribution has been predicted to obey a particular ``universality relation'', namely to have opposite sign in semi-inclusive deeply inelastic scattering (SIDIS) and the Drell-Yan process. We discuss how, on the basis of present HERMES data, this remarkable prediction of the QCD factorization approach to the description of single spin asymmetries related to the Sivers effect could be checked experimentally in future experiments at PAX and COMPASS., Comment: Discussion of recent COMPASS data included, minor corrections, figures and references added, close to published version

Published
2005
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22. Collins effect and single spin azimuthal asymmetriesin the HERMES and COMPASS experiments

Author

K. Goeke, A.V. Efremov, and Peter Schweitzer

Subjects
Physics, Particle physics, Physics and Astronomy (miscellaneous), media_common.quotation_subject, FOS: Physical sciences, Parton, Inelastic scattering, Asymmetry, Azimuth, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Distribution function, Pion, Compass, Fragmentation function, High Energy Physics::Experiment, Nuclear Experiment, Engineering (miscellaneous), media_common
Abstract

Predictions are made for single spin azimuthal asymmetries due to the Collins effect in pion production from semi-inclusive deeply inelastic scattering off transversely and longitudinally polarized targets for the HERMES and COMPASS experiments. The x-dependence of the asymmetries is evaluated using the parton distribution functions from the chiral quark-soliton model. The overall normalization of the predicted asymmetries is determined by the information on the Collins fragmentation function extracted from previous HERMES data on azimuthal asymmetries from a longitudinally polarized target. The single spin asymmetries from the transversely polarized proton target are found to be about 20% for positive and neutral pions both at HERMES and COMPASS. For a longitudinally polarized target we obtain for COMPASS a sin(phi) asymmetry of 1% and a sin(2phi) asymmetry of about 3%., 10 pages, 9 figures, Ref.[29] added

Published
2003
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24. Azimuthal asymmetry in electro-production of neutral pions in semi-inclusive DIS

Author

K. Goeke, A.V. Efremov, and Peter Schweitzer

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Proton, Scattering, media_common.quotation_subject, Asymmetry, Azimuthal asymmetry, Pion, Positron, Fragmentation function, High Energy Physics::Experiment, Nuclear Experiment, media_common
Abstract

Recently HERMES has observed an azimuthal asymmetry in electro-production of neutral pions in semi-inclusive deep-inelastic scattering of unpolarized positrons off longitudinally polarized protons. This asymmetry (like those observed in the production of charged pions) is well reproduced theoretically by using the non-perturbative calculation of the proton transversity distribution in the effective chiral quark-soliton model combined with experimental DELPHI-data on the new T-odd Collins fragmentation function. There are no free, adjustable parameters in the analysis. Using the $z$-dependence of the HERMES azimuthal asymmetry and the calculated transversity distributions the z-dependence of the Collins fragmentation function is obtained. The value obtained from HERMES data is consistent with the DELPHI result, even though these results refer to different scales.

Published
2001
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25. Azimuthal asymmetries in deep inelastic scattering

Author

Maxim V. Polyakov, Diana Urbano, A.V. Efremov, and K. Goeke

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Proton, media_common.quotation_subject, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Asymmetry, Polarized target, Azimuth, High Energy Physics::Experiment, Soliton, Nuclear Experiment, Free parameter, media_common
Abstract

Using the recent experimental data on the left right asymmetry in fragmentation of transversely polarized quarks and the theoretical calculation of the proton transversity distribution in the effective chiral quark soliton model we explain the azimuthal asymmetries in semi-inclusive hadron production on longitudinal (HERMES) and transversely (SMC) polarized targets with no free parameters. On this basis we state that the proton transversity distribution could be successfully measured in future DIS experiments with longitudinally polarized target.

Published
2000
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26. The STAR Time Projection Chamber

Author

K.H. Ackermann, N. Adams, C. Adler, M. Aluyshin, M.A. Ananeva, M. Anderson, G. Averichev, A. Bacher, J. Balewski, O. Balrannikova, J. Baudot, S. Bekele, R. Bellwied, S. Bennett, J. Berger, W. Betts, H. Bichsel, F. Bieser, L. Bland, C. Blyth, A. Bogdanov, B.E. Bonner, R. Bossingham, A. Boucham, S. Bouvier, F.P. Brady, E. Braithwaite, W. Braithwaite, R.L. Brown, V. Budilov, C. Byrd, H. Caines, N. Carlin, J. Carroll, D. Cebra, M.-L. Chen, W. Chen, Y. Chen, S. Chernenko, M. Cherney, A. Chikanian, J.T.M. Chrin, W. Christie, J.-P. Coffin, L. Conin, T.M. Cormier, J. Cramer, H.J. Crawford, A. Das, W. Deng, A.A. Derevschikov, L. Didenko, W. Dominik, J.E. Draper, V. Dunin, J. Dunlop, H. Dyke, W.R. Edwards, V. Eckardt, A.V. Efremov, V. Emelianov, J. Engelage, G. Eppley, B. Erazmus, A. Etkin, P. Fachini, V. Faine, M.I. Ferguson, H. Fessler, E. Finch, Y. Fisyak, D. Flierl, K.J. Foley, D. Fritz, N. Gagunashvili, M. Germain, V. Ghazikhanian, M. Gilkes, S. Giliberto, J. Grabski, O. Grachov, D. Greiner, L.C. Greiner, V. Grigoriev, E. Gushin, H. Gutbrod, T.J. Hallman, D. Hardtke, J.W. Harris, M. Heffner, S. Heppelmann, A. Hirsch, E. Hjort, G.W. Hoffmann, M. Horsley, H. Huang, T. Humanic, H. Huemmler, T. Huyck, G.J. Igo, Yu.I. Ivanshin, P. Jacobs, W. Jacobs, S. Jacobson, R. Jared, P. Jones, E.G. Judd, F. Jundt, M. Kaplan, V. Kaplin, D. Keane, V. Khodyrev, J. Klay, S. Klein, L. Kolobashkina, A. Konstantinov, L. Kotchenda, I. Kotov, M. Kramer, P. Kravtsov, C. Kuhn, G.J. Kunde, R. Kutuev, M. Lamont, J.S. Lange, B. Lasiuk, F. Laue, A. Lebedev, Z. Lee, T. LeCompte, B. Leonhardt, V. Leontiev, null Leszczynski, M.J. LeVine, Q. Li, Z. Li, C.J. Liaw, J. Lin, S.J. Lindenbaum, H. Liu, M. Lisa, A. Ljubicic, W. Llope, G. LoCurto, H. Long, R.S. Longacre, W.A. Love, J.R. Lutz, D. Lynn, L. Madansky, R. Majka, T.M. Makarenko, A. Maliszewski, S. Margetis, K. Marks, L. Martin, J. Marx, H.S. Matis, Yu. Matulenko, T.S. McShane, A. Meshanin, Yu. Melnik, A. Michalon, B. Miller, Z. Milosevich, N. Minaev, R.M. Minor, J. Mitchell, V.A. Moiseenko, D. Moltz, C.F. Moore, M.G. Munhoz, G.S. Mutchler, J.M. Nelson, P. Nevski, V. Nikitin, B. Nilsen, L. Nogach, S. Nurushev, J. Nystrand, G. Odyniec, A. Ogawa, C.A. Ogilvie, V. Okorokov, D. Olson, A. Oltchak, G. Ott, G. Paic, S. Pandey, Y. Panebratsev, S.Y. Panitkin, A. Pavlinov, T. Pawlak, W. Peryt, V. Perevoztchikov, V.A. Petrov, Yu. Petukhov, W. Pinganaud, E. Platner, J. Pluta, N. Porile, J. Porter, A.M. Poskanzer, M. Przewlocki, D. Prindle, E. Potrebenikova, C. Pruneau, G. Rai, O. Ravel, R.L. Ray, D. Razin, S. Razin, J. Reid, F. Retiere, A. Ridiger, J. Riso, H.-G. Ritter, J.B. Roberts, D. Roehrich, O. Rogachevskiy, A. Rollefson, J.L. Romero, C. Roy, M. Runco, D.E. Russ, V. Rykov, I. Sakrejda, P. Saltz, J. Sandweiss, A.C. Saulys, I. Savin, J.J. Schambach, R.P. Scharenberg, N. Schmitz, L.S. Schroeder, A. Schuettauf, M. Schulz, J. Seger, D. Seliverstov, J. Seyboth, P. Seyboth, A. Shalnov, K. Shestermanov, Y. Shi, V.S. Shvetsov, I.N. Silin, N. Smirnoff, R. Snellings, L. Soloviev, J. Sowinski, H.M. Spinka, B. Srivastava, E. Stephenson, R. Stock, M. Strikhanov, B. Stringfellow, H. Stroebele, C. Struck, E. Sugarbaker, C. Suire, A. Sustich, T.J. Symons, E.M. Szanto, A. Szanto de Toledo, J. Takahashi, A. Tang, D. Thein, J.H. Thomas, V. Tikhomirov, V. Tikhonov, M.B. Tonjes, T. Trainor, S. Trentalange, M. Tokarev, V. Trofimov, O. Tsai, C. Tull, K. Turner, T. Ullrich, D.G. Underwood, G. VanBuren, A.M. VanderMolen, A. Vanyashin, A. Vasiliev, I.M. Vasilevski, S. Vigdor, S. Voloshin, C.Q. Vu, F. Wang, H.J. Ward, D. Weerasundra, R. Wells, T. Wenaus, G.D. Westfall, J.P. Whitfield, C. Whitten, H. Wieman, R. Willson, S. Wissink, R. Witt, L. Wood, N. Xu, Z. Xu, A. Yakutin, E. Yamamoto, J. Yang, P. Yepes, A. Yokosawa, V. Yurevich, J. Zhang, W.M. Zhang, N. Zhidkov, D. Zimmerman, R. Zoulkarneev, A. Zubarev, 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), Laboratoire SUBATECH Nantes (SUBATECH), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and STAR

Subjects
Physics, Nuclear and High Energy Physics, Time projection chamber, Physics::Instrumentation and Detectors, business.industry, 010308 nuclear & particles physics, Track (disk drive), Resolution (electron density), Observable, Star (graph theory), Engineering physics, 01 natural sciences, Particle identification, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, Stars, 0302 clinical medicine, Optics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], 0103 physical sciences, Data analysis, Nuclear Experiment, business, 010306 general physics
Abstract

The STAR Time Projection Chamber was successfully operated during the first RHIC run in 2000. Most of the STAR contributions reported in these proceedings are based on the analysis of data from the TPC. In this article, we show that the performance achieved by the TPC, in terms of track reconstruction, position resolution, and particle identification are well suited for measuring precise and reliable physics observables.

Published
1999
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27. Measurement of the cross section for high-pThadron production in the scattering of160−GeV/cmuons off nucleons

Author

S. Grabmüller, A. Srnka, Michael Kramer, J. Pochodzalla, Ch. Höppner, P.D. Eversheim, J.H. Koivuniemi, M. V. Zavertyaev, C. Marchand, T. Negrini, V. Frolov, K. Schmidt, J.M. Friedrich, V. Rapatsky, Andrea Ferrero, P. Schiavon, Achim Richter, Norihiro Doshita, N. d'Hose, J. Bisplinghoff, S. Koblitz, C. Adolph, R. Jahn, L. Schmitt, I. Uman, S. Takekawa, Oleg V. Ivanov, Miroslav Sulc, F. Hinterberger, D. Kang, K. Königsmann, L. Lauser, A. Maggiora, S. Ramos, François Herrmann, Vladimir Nikolaenko, A. N. Sissakian, A.G. Olshevsky, L. Steiger, A. Padee, G.V. Khaustov, E. Zemlyanichkina, A. Bressan, W. Schröder, O.P. Gavrichtchouk, N. Horikawa, T. Nagel, Yu.V. Mikhailov, L. Sinha, T. Matsuda, N.V. Vlassov, S.S. Dasgupta, R. Gushterski, A.A. Lednev, W. Meyer, Maria Liz Crespo, I.A. Savin, Sergey Donskov, K. Schönning, Alexey Antonov, M. Slunečka, Günter Baum, O.Yu. Shevchenko, S. Levorato, T. Michigami, T. Guthörl, P. Sznajder, D. Neyret, A. Lehmann, A. Mutter, E. M. Kabuss, A. Bravar, S. Sosio, S. Paul, S. Neubert, V. Jary, B. Gobbo, S. Tessaro, A. Mann, Yu. Kisselev, R. Garfagnini, Marcin Stolarski, M. Finger, S. Uhl, N. I. Zhuravlev, M.G. Alekseev, A. Sandacz, F. Nerling, Marcello Giorgi, Federica Sozzi, M. Ziembicki, A.V. Efremov, E. Rondio, Moinester, Michal Dziewiecki, K. Klimaszewski, A. Morreale, S. Schopferer, M. Ostrick, V.D. Samoylenko, Elena Rocco, Lei Wang, M. Virius, Andres Cicuttin, Yu.A. Khokhlov, J. Polak, S. Platchkov, V.N. Kolosov, G. Reicherz, C. Franco, R. Panknin, Anne-Laure Martin, Laura Silva, N.S. Rossiyskaya, F. Haas, Christian Schill, K. Zaremba, G.I. Smirnov, S. Dalla Torre, C. Hess, F. H. Heinsius, J. Pretz, G. Piragino, S. Sarkar, R. Geyer, V.A. Polyakov, A. Grasso, P. Bordalo, C. Quintans, E. Perevalova, Jean-Francois Rajotte, J. Barth, A. Zvyagin, D.I. Ryabchikov, I. Konorov, V. Duic, E. Burtin, V.F. Konstantinov, A.S. Nunes, D. von Harrach, D. Panzieri, A. Austregesilo, G. Sbrizzai, W. Wislicki, Janusz Marzec, S. Dasgupta, C. Elia, Gerhard K. Mallot, T. Liška, L. G. Tkatchev, H. Fischer, A. Amoroso, Maxence Vandenbroucke, R. Joosten, N. du Fresne von Hohenesche, Yu. Alexandrov, S. Ishimoto, T. Schlüter, A. Magnon, Bakur Parsamyan, R. Birsa, R. Kuhn, Roland Windmolders, K. Bicker, A. Korzenev, K. Kondo, L. Dhara, S. Das, C. Braun, M. Chiosso, R. Bertini, T. Iwata, Y. Bedfer, Johannes Bernhard, A. Guskov, B. Badelek, S. U. Chung, K. Kurek, M. Bettinelli, O. Kouznetsov, A. Nagaytsev, F. Balestra, Aram Kotzinian, B. Ketzer, Franco Bradamante, A. Filin, M.G. Sapozhnikov, D.V. Peshekhonov, P. Jasinski, G. Pesaro, J. ter Wolbeek, I. Gnesi, W. Eyrich, Nour Makke, J. Bieling, M. Quaresma, W.-D. Nowak, G.V. Meshcheryakov, Matthias Schott, F. Tessarotto, Z.V. Kroumchtein, O.Yu. Denisov, F. Kunne, G. D. Alexeev, W. Dünnweber, S. G. Gerassimov, Fabrice Gautheron, M. A. Faessler, V.Yu. Alexakhin, R. Sulej, Frank Klein, H. Wollny, Yu. Ivanshin, S. Goertz, J. Lichtenstadt, and B. Grube

Subjects
Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Muon, 010308 nuclear & particles physics, Scattering, Nuclear Theory, Hadron, 01 natural sciences, Nuclear physics, Cross section (physics), 0103 physical sciences, COMPASS experiment, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The cross section for production of charged hadrons with high transversemomenta in scattering of 160 GeV/c muons off nucleons at low photonvirtualities has been measured at the COMPASS experiment at CERN. The results,which cover transverse momenta from 1.1 to 3.6 GeV/c, are compared to anext-to-leading order perturbative Quantum Chromodynamics (NLO pQCD)calculation in order to evaluate the applicability of pQCD to this process inthe kinematic domain of the experiment. The shape of the calculateddifferential cross section as a function of transverse momentum is found to bein good agreement with the experimental data, but the normalization isunderestimated by NLO pQCD. This discrepancy may point towards the relevance ofterms beyond NLO in the pQCD framework. The dependence of the cross section onthe pseudo-rapidity and on the charge of the hadrons is also discussed.

Published
2013
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28. Single spin asymmetries of pion production in twist-3 QCD

Author

Oleg Teryaev, A.V. Efremov, and V.M. Korotkiyan

Subjects
Quark, Physics, Quantum chromodynamics, Nuclear and High Energy Physics, Particle physics, High Energy Physics::Lattice, Nuclear Theory, High Energy Physics::Phenomenology, Parton, Gluon, Nuclear physics, Pion, High Energy Physics::Experiment, Sum rule in quantum mechanics, Twist, Nuclear Experiment, Spin-½
Abstract

Single spin parton asymmetries for high p T gluon and quark production are calculated. Using the sum rules for the twist-3 quark-gluon correlators and the twist-2 distribution function, we propose an explanation for the difference in sign of asymmetries for π + , π 0 and π − production.

Published
1995
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29. Relation between transverse momentum dependent distribution functions and parton distribution functions in the covariant parton model approach

Author

Petr Zavada, A.V. Efremov, Oleg Teryaev, and Peter Schweitzer

Subjects
Physics, Quark, Nuclear and High Energy Physics, Particle physics, Distribution function, High Energy Physics::Phenomenology, Parton, Covariant transformation, Rest frame, Lorentz covariance, Nuclear Experiment, Nucleon, Symmetric probability distribution
Abstract

We derive relations between transverse momentum dependent distribution functions (TMDs) and the usual parton distribution functions (PDFs) in the 3D covariant parton model, which follow from Lorentz invariance and the assumption of a rotationally symmetric distribution of parton momenta in the nucleon rest frame. Using the known PDFs f_1(x) and g_1(x) as input we predict the x- and pT-dependence of all twist-2 T-even TMDs.

Published
2011
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30. The transverse momentum dependent distribution functions in the bag model

Author

Feng Yuan, Harut Avakian, A.V. Efremov, and Peter Schweitzer

Subjects
Physics, Quark, Nuclear and High Energy Physics, Angular momentum, Quark model, High Energy Physics::Phenomenology, FOS: Physical sciences, Parton, Fermion, High Energy Physics - Phenomenology, Distribution function, High Energy Physics - Phenomenology (hep-ph), Quantum electrodynamics, Phenomenology (particle physics), Ansatz
Abstract

Leading and subleading twist transverse momentum dependent parton distribution functions (TMDs) are studied in a quark model framework provided by the bag model. A complete set of relations among different TMDs is derived, and the question is discussed how model-(in)dependent such relations are. A connection of the pretzelosity distribution and quark orbital angular momentum is derived. Numerical results are presented, and applications for phenomenology discussed. In particular, it is shown that in the valence-x region the bag model supports a Gaussian Ansatz for the transverse momentum dependence of TMDs., Comment: 26 pages

Published
2010
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31. On the handedness in polarized τ → a1ν → 3πν decay

Author

N.A. Törnqvist, A.V. Efremov, and Lech Mankiewicz

Subjects
Physics, Hadronic decay, Nuclear and High Energy Physics, Particle physics, Pion, media_common.quotation_subject, Observable, Elementary particle, Neutrino, Polarization (waves), Asymmetry, Helicity, media_common
Abstract

We discuss the polarization assymetries in the reactions e + e − → τ + τ − and τ → a 1 ν τ → 3 πν τ at the Z 0 . The a 1 → 3 π decay is particularly interesting since it is the lightest hadronic decay in which the helicity of the initial state can be determined from the distribution of the final particle momenta. Thus it is the first example of a helicity self-analysing strong decay, as Λ → N π is for weak decays. The relevant observable is the “handedness” asymmetry introduced earlier. It can be used together with two other asymmetries to determine both polarization of τ and left-handedness of ν τ , and to check the self-consistency of the analysis.

Published
1992
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32. PRETZELOSITY DISTRIBUTION FUNCTION $h_{1T}^ \bot $

Author

H. Avakian, Feng Yuan, Peter Schweitzer, and A.V. Efremov

Subjects
Physics, Particle physics, Distribution function, Distribution (number theory), Transverse momentum, Parton, Twist, Nuclear Experiment, Helicity
Abstract

The 'pretzelosity' distribution is discussed. Theoretical properties, model results, and perspectives to access experimental information on this leading twist, transverse momentum dependent parton distribution function are reviewed. Its relation to helicity and transversity distributions is highlighted.

Published
2009
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33. Azimuthal spin asymmetries in light-cone constituent quark models

Author

Barbara Pasquini, A.V. Efremov, S. Boffi, and Peter Schweitzer

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, hep-ex, media_common.quotation_subject, Quark model, Constituent quark, FOS: Physical sciences, Parton, hep-ph, Deep inelastic scattering, Asymmetry, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Phenomenology, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Light cone, High Energy Physics::Experiment, Nucleon, Nuclear Experiment, media_common, Spin-½
Abstract

We present results for all leading-twist azimuthal spin asymmetries in semi-inclusive lepton-nucleon deep-inelastic scattering due to T-even transverse-momentum dependent parton distribution functions on the basis of a light-cone constituent quark model. Attention is paid to discuss the range of applicability of the model, especially with regard to the scale dependence of the observables and the transverse-momentum dependence of the distributions. We find good agreement with available experimental data and present predictions to be further tested by future CLAS, COMPASS and HERMES data., Comment: 23 pages, 14 figures, 1 table

Published
2009
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34. Transverse momentum dependent distribution functionh1T⊥and the single spin asymmetryAUTsin (3ϕ−3S)

Author

A.V. Efremov, H. Avakian, Feng Yuan, and Peter Schweitzer

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Distribution function, media_common.quotation_subject, Parton, Twist, Nucleon, Relativistic quantum chemistry, Helicity, Asymmetry, media_common, Spin-½
Abstract

The leading twist transverse momentum dependent parton distribution function ${h}_{1T}^{\ensuremath{\perp}}$ is studied. We review the theoretical properties of this function, and compute it in the bag model. We find in the bag model an interesting relation, and observe it to hold also in other relativistic models: The difference between helicity and transversity distributions, often said to be a 'measure of relativistic effects' in the nucleon, is related to ${h}_{1T}^{\ensuremath{\perp}}$. This function is chirally odd and can be accessed in combination with the Collins effect in semi-inclusive deep-inelastic scattering, where it gives rise to an azimuthal single spin asymmetry proportional to $\mathrm{sin} (3\ensuremath{\phi}\ensuremath{-}{\ensuremath{\phi}}_{S})$. We discuss preliminary COMPASS data on that observable and make predictions for future experiments on various targets at JLab, COMPASS, and HERMES.

Published
2008
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35. Spin structure of the nucleon and axial anomaly

Author

A.V. Efremov, O.V. Teryaev, and Jacques Soffer

Subjects
Coupling constant, Physics, Nuclear and High Energy Physics, Spin polarization, High Energy Physics::Lattice, Nuclear Theory, High Energy Physics::Phenomenology, Spin structure, Quantum electrodynamics, Proton spin crisis, Condensed Matter::Strongly Correlated Electrons, Sum rule in quantum mechanics, Anomaly (physics), Nuclear Experiment, Nucleon, Spin-½
Abstract

The gluon spin distribution function is shown to contribute to the spin structure of a proton via the axial anomaly. It modifies the original Ellis-Jaffe sum rule and can help in resolving the “Spin Crisis”. The axial anomaly renormalization, the evolution equations and the connection of the quark content of the proton spin with the η′-meson coupling constants are also considered.

Published
1990
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36. Collins Effect in SIDIS and in e+e− Annihilation

Author

A.V. Efremov, Peter Schweitzer, and K. Goeke

Subjects
Physics, High Energy Physics - Phenomenology, Particle physics, High Energy Physics - Phenomenology (hep-ph), Annihilation, Distribution (number theory), Nuclear Theory, High Energy Physics::Phenomenology, Fragmentation function, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment, Nucleon
Abstract

We review the present understanding of the nucleon transversity distribution and Collins fragmentation function, based on Ref.\cite{Efremov:2006qm}, and discuss how Drell-Yan experiments will improve it., Comment: Talk at Moscow ICHEP 26.7-2.8.2006 and Kyoto Symposium on Spin Physics 2-7.10.2006, 5 pages, 5 figures, AIP style files included. Some pictures chenged, one reference added, typos and some errors in formulas are corrected

Published
2007
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37. Transverse momentum dependence of the quark helicity distributions and the Cahn effect in double-spin asymmetryALLin semiinclusive DIS

Author

A.V. Efremov, Aram Kotzinian, B. Parsamyan, and Mauro Anselmino

Subjects
Quark, Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Particle physics, Distribution function, Quark model, High Energy Physics::Experiment, Parton, Deep inelastic scattering, Helicity, Particle identification
Abstract

Within the LO QCD parton model of Semi-Inclusive Deep Inelastic Scattering, $\ensuremath{\ell}N\ensuremath{\rightarrow}\ensuremath{\ell}hX$, with unintegrated quark distribution and fragmentation functions, we study the ${\mathbit{P}}_{hT}$ dependence of the double longitudinal-spin asymmetry ${A}_{LL}$. We include $1/Q$ kinematic corrections, which induce an azimuthal modulation of the asymmetry, analogous to the Cahn effect in unpolarized SIDIS. We show that a study of ${A}_{LL}$ and of the weighted DSA ${A}_{LL}^{\mathrm{cos} {\ensuremath{\phi}}_{h}}$ allows to extract the transverse momentum dependence of the unintegrated helicity distribution function ${g}_{1L}^{q}(x,{k}_{\ensuremath{\perp}})$ [or $\ensuremath{\Delta}q(x,{k}_{\ensuremath{\perp}})]$. Predictions, based on some models for the unknown functions, are given for ongoing COMPASS, HERMES and JLab experiments.

Published
2006
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38. Sivers effect in the Drell-Yan process at BNL RHIC

Author

John Collins, A.V. Efremov, Andreas Metz, M. Grosse Perdekamp, B. Meredith, Klaus Goeke, Peter Schweitzer, and S. Menzel

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, High Energy Physics::Phenomenology, Nuclear Theory, Drell–Yan process, High Energy Physics::Experiment, Statistical analysis, Nuclear Experiment, Deep inelastic scattering, Polarized target
Abstract

On the basis of a fit to the Sivers effect in deep-inelastic scattering, we make predictions for single-spin asymmetries in the Drell-Yan process at BNL RHIC.

Published
2006
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39. Sivers effect in semiinclusive deeply inelastic scattering

Author

John Collins, Klaus Goeke, S. Menzel, A.V. Efremov, Peter Schweitzer, and Andreas Metz

Subjects
Physics, Quantum chromodynamics, Nuclear and High Energy Physics, Particle physics, Distribution (number theory), media_common.quotation_subject, High Energy Physics::Phenomenology, FOS: Physical sciences, Parton, Inelastic scattering, Deep inelastic scattering, Asymmetry, Nuclear physics, High Energy Physics - Phenomenology, symbols.namesake, High Energy Physics - Phenomenology (hep-ph), symbols, High Energy Physics::Experiment, Gaussian network model, media_common, Spin-½
Abstract

The Sivers function is extracted from HERMES data on single spin asymmetries in semi-inclusive deeply inelastic scattering. Our analysis use a simple Gaussian model for the distribution of transverse parton momenta, together with the flavor dependence given by the leading 1/Nc approximation and a neglect of the Sivers antiquark distribution. We find that within the errors of the data these approximations are sufficient., Small additions, Fig.2 corrected, references and one figure added, correction in Eq.(13), version accepted for publication

Published
2006
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40. Transversity distribution function in hard scattering of polarized protons and antiprotons in the PAX experiment

Author

A.V. Efremov, Peter Schweitzer, and K. Goeke

Subjects
Physics, Quark, Particle physics, Physics and Astronomy (miscellaneous), Scattering, media_common.quotation_subject, Nuclear Theory, High Energy Physics::Phenomenology, FOS: Physical sciences, Asymmetry, High Energy Physics - Phenomenology, Distribution function, Pair production, High Energy Physics - Phenomenology (hep-ph), Antiproton, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, Engineering (miscellaneous), Lepton, Spin-½, media_common
Abstract

Estimates are given for the double spin asymmetry in lepton pair production from collisions of transversely polarized protons and antiprotons for the kinematics of the recently proposed PAX experiment at GSI on the basis of predictions for the transversity distribution from the chiral quark soliton model., Comment: 5 pages, 5 figures, references added, to appear in EPJC

Published
2004
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41. Azimuthal asymmetries at CLAS: Extraction ofea(x)and prediction ofAUL

Author

Klaus Goeke, A.V. Efremov, and Peter Schweitzer

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Proton, Scattering, Nuclear Theory, Electron, Inelastic scattering, Nuclear physics, Azimuth, Pion, Distribution function, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, Beam (structure)
Abstract

The first information on the chirally odd twist-3 proton distribution function ${e}^{a}(x)$ is extracted from the azimuthal asymmetry ${A}_{\mathrm{LU}}$ in the electroproduction of pions from deeply inelastic scattering of longitudinally polarized electrons off unpolarized protons, which has been recently measured by the CLAS Collaboration. Furthermore parameter-free predictions are made for the azimuthal asymmetries ${A}_{\mathrm{UL}}$ from scattering of an unpolarized beam on a polarized proton target for CLAS kinematics.

Published
2003
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42. Sivers vs. Collins effect in azimuthal single spin asymmetries in pion production in SIDIS

Author

Klaus Goeke, A.V. Efremov, and Peter Schweitzer

Subjects
Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Particle physics, FOS: Physical sciences, Azimuth, Nuclear physics, High Energy Physics - Phenomenology, Distribution function, Pion, High Energy Physics - Phenomenology (hep-ph), Compass, Bibliography, High Energy Physics::Experiment, Spin-½, Lepton
Abstract

Recently it has been argued that the transverse momentum dependent twist-2 Sivers distribution function does not vanish in QCD. Therefore both, the Collins and Sivers effects, should be considered in order to explain the azimuthal single spin asymmetries A(UL) in pion production in semi-inclusive deeply inelastic lepton scattering of a longitudinally polarized target. On the basis of presently available phenomenological information on the Sivers function we estimate that for those asymmetries A(UL) in the kinematic region of the HERMES experiments the Sivers effect can be neglected with respect to the Collins effect. It is argued that the same feature holds also for the COMPASS and CLAS experiments. This justifies theoretical approaches to understand the HERMES data on the basis of the Collins effect only., Comment: 8 pages, 4 figures. References added, small changes in text, Appendix added

Published
2003
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43. Gluon and quark distributions in large N_c QCD: theory vs. phenomenology

Author

A.V. Efremov, P.V. Pobylitsa, and K. Goeke

Subjects
Quantum chromodynamics, Quark, Physics, Nuclear and High Energy Physics, Particle physics, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), High Energy Physics::Lattice, Nuclear Theory, High Energy Physics::Phenomenology, FOS: Physical sciences, High Energy Physics::Experiment, Gluon
Abstract

We present the QCD analysis of the behavior of quark and gluon distributions in the limit of a large number of colors N_c. We show that the results agree qualitatively with the phenomenological data. In particular we draw attention to the fact that the polarized gluon distribution is suppressed at large N_c compared to the unpolarized one., Comment: 8 pages, v.2: references added

Published
2000
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44. Axial anomaly and sum rule for the photon spin structure function

Author

Oleg Teryaev and A.V. Efremov

Subjects
Physics, Scattering amplitude, Renormalization, Nuclear and High Energy Physics, Photon, Quantum electrodynamics, Quantum mechanics, Photon polarization, Sum rule in quantum mechanics, Inelastic scattering, Spin structure, Polarization (waves)
Abstract

It is shown that the first moment of the spin structure function g γ 1 of a polarized photon is determined by the axial anomaly. Renormalization of the anomaly determines the Q 2 -dependence of the corresponding sum rule.

Published
1990
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45. The polarized TMDs in the covariant parton model approach

Author

Oleg Teryaev, Peter Schweitzer, A.V. Efremov, and Petr Zavada

Subjects
Physics, History, Particle physics, FOS: Physical sciences, Parton, Lorentz covariance, Rest frame, Symmetric probability distribution, High Energy Physics - Experiment, Computer Science Applications, Education, High Energy Physics - Phenomenology, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Distribution function, Covariant transformation, Nuclear Experiment, Nucleon, Spin-½
Abstract

We derive relations between polarized transverse momentum dependent distribution functions (TMDs) and the usual parton distribution functions (PDFs) in the 3D covariant parton model, which follow from Lorentz invariance and the assumption of a rotationally symmetric distribution of parton momenta in the nucleon rest frame. Using the known PDF $g_{1}^{q}(x)$ as input we predict the $x$- and $\mathbf{p}_{T}$-dependence of all polarized twist-2 naively time-reversal even (T-even) TMDs., Comment: 6 pages, 2 figures, Contribution to the Proceedings of the 19th International Spin Physics Symposium (SPIN2010), J\"{u}lich, Germany, September 27 - October 2, 2010

Published
2011
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49. Factorization and asymptotic behaviour of pion form factor in QCD

Author

Anatoly Radyushkin and A.V. Efremov

Subjects
Physics, Quantum chromodynamics, Nuclear and High Energy Physics, Particle physics, High Energy Physics::Lattice, Form factor (quantum field theory), Gluon, symbols.namesake, Pion, Factorization, Weierstrass factorization theorem, symbols, Feynman diagram, High Energy Physics::Experiment, Perturbation theory (quantum mechanics), Mathematical physics
Abstract

We outline an all-orders, all-logarithms proof of the factorization theorem for the pion electromagnetic form factor in QCD. The proof is based on the analysis of the large momentum behaviour of Feynman diagrams in a parametric representation.

Published
1980
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