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Start Over Author "Herbert Löhner" Publisher american physical society (aps)
27 results on '"Herbert Löhner"'

1. Three-Body Nature ofN*andΔ*Resonances from Sequential Decay Chains

Author

Frank Klein, V. Sokhoyan, A. Wilson, E. Gutz, M. Pfeiffer, S. Shende, J. Junkersfeld, J. G. Messchendorp, R. Beck, D. V. Novinski, Ch. Schmidt, M. Kotulla, D. Walther, V. A. Nikonov, R. Castelijns, Matthew Lang, Wolfgang Hillert, A. Thiel, A. V. Anisovich, I. Horn, S. Lugert, H. Kalinowsky, Cbelsa, U. Thoma, Eberhard Klempt, B. Bantes, V. Kleber, D. Elsner, Volker Metag, H. van Pee, R. Gregor, R. Varma, T. Mertens, Friedrich Klein, Herbert Löhner, R. W. Novotny, Yu. A. Beloglazov, B. Krusche, A. Roy, A. V. Sarantsev, Ph. Hoffmeister, O. Bartholomy, L. M. Pant, H. Dutz, S. Kammer, Bernard Metsch, Frank Frommberger, D. Piontek, Ch. Wendel, Ch. Funke, I. V. Lopatin, V. V. Sumachev, H. Schmieden, V. Crede, D. E. Bayadilov, A. B. Gridnev, Mariana Nanova, A. Süle, I. Jaegle, M. Ostrick, D. Trnka, J. C. S. Bacelar, R. Ewald, T. Szczepanek, and M. Fuchs

Subjects
Physics, Partial wave analysis, Nuclear Theory, General Physics and Astronomy, Dalitz plot, Delta baryon, Particle decay, Pion, Isobar, High Energy Physics::Experiment, Decay chain, Atomic physics, Nuclear Experiment, Nucleon
Abstract

The N pi(0)pi(0) decays of positive-parity N* and Delta* resonances at about 2 GeV are studied at ELSA by photoproduction of two neutral pions off protons. The data reveal clear evidence for several intermediate resonances: Delta(1232), N(1520)3/2(-), and N(1680)5/2(+), with spin parities J(P) = 3/2(+), 3/2(-), and 5/2(+). The partial wave analysis (within the Bonn-Gatchina approach) identifies N(1440)1/2(+) and the N(pi pi)s (wave) (abbreviated as N sigma here) as further isobars and assigns the final states to the formation of nucleon and Delta resonances and to nonresonant contributions. We observe the know Delta(1232)pi decays of Delta(1910)1/2(+), Delta(1920)3/2(+), Delta(1905)5/2(+), Delta(1950)7/2(+), and of the corresponding spin-parity series in the nucleon sector, N(1880)1/2(+), N(1900)3/2(+), N(2000)5/2(+), and N(1990)7/2(+). For the nucleon resonances, these decay modes are reported here for the first time. Further new decay modes proceed via N(1440)1/2(pi)(+), N(1520)3/2(pi)(-) , N(1680)5/2(pi)(+), and N sigma. The latter decay modes are observed in the decay of N* resonances and at most weakly in Delta(*) decays. It is argued that these decay modes provide evidence for a 3-quark nature of N* resonances rather than a quark-diquark structure.

Published
2015
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2. Observation of Direct Photons in Central158AGeVP208b+P208bCollisions

Author

H. Delagrange, Shunji Nishimura, K. Yagi, H. Kalechofsky, MV Manzano Martin, S. K. Nayak, Md. F. Mir, Madan M. Aggarwal, S. Dutt, S. Pavliouk, M. L. Purschke, H. Naef, A. Nianine, Y. Yokota, Yasuo Miake, C. Blume, S. Neumaier, L. Luquin, V. Djordjadze, G. Sood, R. Cherbatchev, Sanjeev Singh Sambyal, V. S. Bhatia, M. Kurata, A. Kugler, Z.K. Böröcz, R. Santo, E.-M. Bohne, B. W. Kolb, Gerrit Jan van Nieuwenhuizen, I. Hrivnacova, O. P. Gavrishchuk, G. Stefanek, S. Garpman, A.S. Vodopianov, D. P. Mahapatra, Agneta Oskarsson, R. Kamermans, P. Steinberg, S. P. Sorensen, I. Otterlund, K. El Chenawi, T. K. Nayak, M. D. Trivedi, Y.Y. Lee, V. Nikitine, Peter M. Nilsson, P. Foka, G.S. Shabratova, K. Söderström, T. Svensson, S. Knoche, E. Stenlund, A.L.S. Angelis, Klaus Johannes Reygers, F. Retiere, D. P. Morrison, B.N. Gus'kov, W. Pinganaud, A. Agnihotri, P. W. Stankus, G. R. Young, Herbert Löhner, G. C. Mishra, Zubayer Ahammed, Joakim Nystrand, Krzysztof Karpio, N. Solomey, Gunther Roland, M. R. Dutta Majumdar, M. Pachr, V. Astakhov, D. Bucher, N. v. Eijndhoven, Hiroyuki Sako, Tatsuya Chujo, S. K. Badyal, Jan Rak, J. Urbahn, Y. Schutz, K. Karadjev, E. C. v. d. Pijll, Sergey Fokin, N.A. Kuzmin, Y. P. Viyogi, Bikash Sinha, A. Maximov, D. Stüken, I. Langbein, I. Sibiriak, R. Higuchi, Sergey Nikolaev, S. Eliseev, S. Kees, V. Avdeitchikov, M. P. Decowski, P. Donni, U. v. Poblotzki, V. Arefiev, T. C. Awes, Teodor Siemiarczuk, Sukalyan Chattopadhyay, G. Martínez, T. Krümpel, M. S. Ganti, V. Petracek, Kh Kampert, L. Rosselet, I. Doubovik, A. C. Das, Vladislav Manko, R. Bock, F. Plasil, H. Büsching, A. A. Tsvetkov, Bolek Wyslouch, A. Buijs, Bedangadas Mohanty, T. Peitzmann, R. Glasow, B. K. Nandi, A.L. Lebedev, P. Kulinich, Nikolai V Slavine, Y. Miyamoto, Mikhail Ippolitov, G. Mgebrichvili, S. Bathe, Shiv K. Gupta, Michal Sumbera, K. Enosawa, I. Koutcheryaev, V. S. Ramamurthy, S. Kato, F. E. Obenshain, D. S. Mukhopadhyay, P.V.K.S. Baba, L. Tykarski, I. Roufanov, H. Å. Gustafsson, F. J M Geurts, T. K. Ghosh, V.G. Antonenko, S. Vörös, H. H. Gutbrod, Hans Rudolf Schmidt, Petr Nomokonov, Rashmi Raniwala, A. A. Vinogradov, Susumu Sato, B. Batiounia, T. Bernier, N. K. Rao, K. B. Bhalla, M. J. Mora, H. Schlagheck, I. Kosarev, Sudhir Raniwala, J. M. Rubio, Lars Carlén, David Olle Rickard Silvermyr, C. Roy, K. Kurita, C. Barlag, V. Chalyshev, C. Klein-Bösing, T. H. Shah, and A. Claussen

Subjects
Physics, Particle physics, Large Hadron Collider, Photon, Nuclear Theory, Hadron, General Physics and Astronomy, Elementary particle, Spectral line, Massless particle, Nuclear physics, Quark–gluon plasma, High Energy Physics::Experiment, Nuclear Experiment, Boson
Abstract

A measurement of direct photon production in {sup 208}Pb+ {sup 208}Pb collisions at 158A GeV has been carried out in the CERN WA98 experiment. The invariant yield of direct photons in central collisions is extracted as a function of transverse momentum in the interval 0.5 1.5 GeV/c . The result constitutes the first observation of direct photons in ultrarelativistic heavy-ion collisions. It could be significant for diagnosis of quark-gluon-plasma formation.

Published
2000
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3. Three-Pion Interferometry Results from CentralPb+PbCollisions at158AGeV/c

Author

M. Kurata, H. Kalechofsky, [No Value] Antonenko, Krzysztof Karpio, H. Naef, A. Nianine, MV Manzano Martin, Jan Rak, V. S. Bhatia, H. Delagrange, Trivedi, L. Rosselet, Md. F. Mir, T. H. Shah, K. Yagi, A. A. Vinogradov, M. Pachr, Kh Kampert, R. Bock, A. Claussen, B. Batiounia, G. Stefanek, C. Blume, E.-M. Bohne, [No Value] Doubovik, David Olle Rickard Silvermyr, T. C. Awes, O. P. Gavrishchuk, P. Kulinich, Nikolai V Slavine, D. S. Mukhopadhyay, Gunther Roland, P. Foka, K. Kurita, Shunji Nishimura, Ganti, V. S. Ramamurthy, Z.K. Böröcz, N. van Eijndhoven, L. Luquin, [No Value] Arefiev, G. R. Young, R. Santo, G. C. Mishra, R. Kamermans, A.L.S. Angelis, C. Roy, C. Barlag, T. Krümpel, G.S. Shabratova, T. K. Nayak, Subhasis Chattopadhyay, Agneta Oskarsson, M. P. Decowski, [No Value] Nikitine, K. Söderström, S. Pavliouk, M. L. Purschke, Teodor Siemiarczuk, S. Garpman, D. P. Mahapatra, P. W. Stankus, A. Maximov, H. A. Gustafsson, [No Value] Manko, D. Stüken, K. B. Bhalla, M. J. Mora, S. K. Nayak, S. Neumaier, Herbert Löhner, EC van der Pijll, Sergey Nikolaev, Yasuo Miake, Joakim Nystrand, S. Eliseev, S. P. Sorensen, Y. P. Viyogi, Peter M. Nilsson, P. Steinberg, Klaus Johannes Reygers, D. Bucher, K. Karadjev, S. Knoche, Sergey Fokin, F. Retiere, K. Enosawa, S. Kato, T. K. Ghosh, [No Value] Astakhov, Zubayer Ahammed, A. Agnihotri, Mikhail Ippolitov, A. Kugler, N. Solomey, S. Dutt, C. Klein-Bösing, Bedangadas Mohanty, R. Glasow, A.L. Lebedev, [No Value] Petracek, S. Vörös, [No Value] Koutcheryaev, [No Value] Djordjadze, Michal Sumbera, H. Schlagheck, L. Tykarski, A. C. Das, N. Kuzmin, Lars Carlén, S Bathe, Sudhir Raniwala, J. M. Rubio, F. J M Geurts, H. H. Gutbrod, Petr Nomokonov, [No Value] Avdeitchikov, Rashmi Raniwala, T. Bernier, N. K. Rao, F. Plasil, H. Büsching, B. K. Nandi, G. Mgebrichvili, S. Kees, T. Peitzmann, U. von Poblotzki, Madan M. Aggarwal, F. E. Obenshain, P.V.K.S. Baba, Y. Miyamoto, Shiv K. Gupta, [No Value] Langbein, B. W. Kolb, A. A. Tsvetkov, [No Value] Otterlund, [No Value] Kosarev, Bolek Wyslouch, K. El Chenawi, A. Buijs, Mrd Majumdar, Susumu Sato, [No Value] Sibiriak, S. K. Badyal, B. Guskov, Bikash Sinha, R. Cherbatchev, A.S. Vodopianov, G. J. van Nieuwenhuizen, P. Donni, D. P. Morrison, W. Pinganaud, [No Value] Chalyshev, Tatsuya Chujo, Y.Y. Lee, T. Svensson, E. Stenlund, J. Urbahn, Y. Schutz, R. Higuchi, G. Martinez, Y. Yokota, Sanjeev Singh Sambyal, [No Value] Hrivnacova, [No Value] Roufanov, and Hiroyuki Sako

Subjects
Nuclear reaction, Nuclear physics, Physics, Particle physics, Pion, Meson, Hadron, General Physics and Astronomy, Elementary particle, Multiplicity (mathematics), Nuclear Experiment, Particle identification, Boson
Abstract

Three-particle correlations have been measured for identified {pi}{sup -} from central 158A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source.

Published
2000
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4. Coherent Bremsstrahlung in theα+pSystem at50MeV/nucleon

Author

Hans Wilschut, F. M. Marqués, L. Aphecetche, A. Kugler, R.S. Simon, Pierre Descouvemont, David D'Enterria, R.H. Siemssen, R. Holzmann, R. Turrisi, Robertus Timmermans, E. Wulf, J. G. Messchendorp, M. Hoefman, J. C. S. Bacelar, H. Huisman, Nasser Kalantar-Nayestanaki, R.W. Ostendorf, H. Delagrange, M. Volkerts, J. S. Díaz, S. Schadmand, van Marc-Jan Goethem, Wagner, German Martinez, H. R. Weller, Herbert Löhner, and Yves Roland Schutz

Subjects
Physics, Elastic scattering, Photon, 010308 nuclear & particles physics, Bremsstrahlung, General Physics and Astronomy, Alpha particle, 7. Clean energy, 01 natural sciences, Nuclear physics, Excited state, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Ground state, Nucleon, P system
Abstract

Photons originating from coherent bremsstrahlung have been measured over a large dynamic range for the reaction of 200 MeV alpha particles with protons. At low photon energies the bremsstrahlung spectrum exhibits the classical behavior with an approximate 1/E-gamma shape. At higher photon energies there is a pronounced contribution from capture into the unbound ground state and first excited state of Li-5. These results allow one, for the first time, to test theoretical models for a consistent description of bremsstrahlung and radiative capture in a complex system. Calculations predict both features qualitatively but fail to account for their relative importance.

Published
2000
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5. High-Precision Proton-Proton Bremsstrahlung Measurements below the Pion-Production Threshold

Author

R.S. Simon, M. Hoefman, A. Kugler, J. C. S. Bacelar, H. Huisman, Nasser Kalantar-Nayestanaki, Hans Wilschut, Mohsen Harakeh, Herbert Löhner, Robertus Timmermans, J. G. Messchendorp, R. Turrisi, Olaf Scholten, R.W. Ostendorf, van Marc-Jan Goethem, S. Schadmand, M. Volkerts, V. Wagner, and KVI - Center for Advanced Radiation Technology

Subjects
Physics, Nuclear physics, Pion, Proton, Phase space, Nuclear Theory, Bremsstrahlung, Isobar, General Physics and Astronomy, DELTA-ISOBAR, Atomic physics, EXCHANGE, Nuclear Experiment
Abstract

An exclusive proton-proton bremsstrahlung measurement has been performed with polarized protons of 190 MeV. Absolute cross sections and analyzing powers have been measured with unprecedented accuracy in a large part of the phase space. The data are compared with state-of-the-art theoretical calculations including higher-order off-shell effects, like the Delta isobar and meson-exchange currents. Surprisingly, the calculations are unable xo describe the data in detail.

Published
1999
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6. Deep-Subthresholdηandπ0Production Probing Pion Dynamics in the ReactionAr+Caat180AMeV

Author

H. Delagrange, S. Hlavac, M. Hoefman, R. W. Novotny, Y. Charbonnier, R. Turrisi, J. Weiss, V. Metag, Rudolf Siemssen, P.H. Vogt, R.S. Simon, R. Holzmann, V. D. Toneev, L. Aphecetche, A. Kugler, Ralf Peter Averbeck, Matthias Wolf, Yves Roland Schutz, H. Ströher, German Martinez, A. Döppenschmidt, K.K. Gudima, P. Tlustý, Hans Wilschut, A. Wolf, Ana Maria Marin, Herbert Löhner, R. Stratmann, F. Wissmann, R.W. Ostendorf, Marek Ploszajczak, M. Appenheimer, J. S. Díaz, V. Wagner, T. Matulewicz, Frederic Lefevre, and van Marc-Jan Goethem

Subjects
Physics, Particle physics, Photon, Meson, Subthreshold conduction, High Energy Physics::Lattice, High Energy Physics::Phenomenology, Nuclear Theory, Bremsstrahlung, General Physics and Astronomy, Nuclear matter, Nuclear physics, Pion, Pi, High Energy Physics::Experiment, Multiplicity (chemistry), Nuclear Experiment
Abstract

We report on a measurement of subthreshold eta and pi(0) mesons in the reaction Ar + Ca at 180A MeV. We find that the ratio of the eta to pi(0) meson-production cross section is more than a factor of 20 smaller than the one expected from threshold-energy scalings of meson production. In addition, the multiplicity of high m(t) pi(0) increases faster with the centrality of the reaction than the multiplicity of the bulk of pi(0) mesons. This behavior is explained by the rescattering of pi mesons in nuclear matter at the origin of most energetic particles.

Published
1999
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7. Contribution ofπ0and η Dalitz decays to the dilepton invariant-mass spectrum in1AGeV heavy-ion collisions

Author

Frederic Lefevre, V. Metag, T. Matulewicz, Yves Roland Schutz, A. Kugler, R.S. Simon, Ralf Peter Averbeck, A. Döppenschmidt, F. Wissmann, R. Pleskac, R. W. Novotny, A.R. Wolf, P.H. Vogt, P. Tlustý, Y. Charbonnier, Hans Wilschut, H. Ströher, R.W. Ostendorf, German Martinez, J. Weiss, H. Delagrange, Ana Maria Marin, S. Hlavac, V. Hejny, R. Holzmann, Herbert Löhner, Rudolf Siemssen, M. Appenheimer, Matthias Wolf, V. Wagner, and J. S. Díaz

Subjects
Systematic error, Physics, Nuclear and High Energy Physics, Particle physics, Range (particle radiation), Spectrometer, Meson, Nuclear Theory, Spectrum (functional analysis), Nuclear physics, Mass spectrum, High Energy Physics::Experiment, Heavy ion, Invariant mass, Nuclear Experiment
Abstract

The Dalitz-decay contributions of pi(0) and eta mesons to the di-electron invariant-mass spectrum at 1A GeV have been obtained from a systematics of inclusive meson production cross sections measured for the collision systems C-12 + C-nat and Ar-40, Ca-40 + Ca-nat in the bombarding-energy range of 0.8-2.0 A GeV. These results are compared with the recently published di-electron mass spectra of the DLS collaboration. Systematic errors and angular-distribution effects are discussed. We conclude that the low-mass part of the DLS data cannot be explained by the Dalitz decays of light neutral mesons only.

Published
1997
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8. Transverse momentum distributions of η mesons in near-threshold relativistic heavy ion reactions

Author

R.S. Simon, W. Kühn, V. Metag, O. Schwalb, Michal Sumbera, Herbert Löhner, F. D. Berg, M. Franke, J. Ritman, H. W. Wilschut, A. E. Raschke, M. Röbig-Landau, L.B. Venema, M. Pfeiffer, M. Notheisen, and R. W. Novotny

Subjects
Physics, Meson, Nuclear Theory, Hadron, General Physics and Astronomy, Delta baryon, Nuclear physics, Baryon, Distribution function, Pion, Transverse mass, High Energy Physics::Experiment, Production (computer science), Atomic physics, Nuclear Experiment
Abstract

Transverse momentum spectra of \ensuremath{\eta} mesons have been measured near the free nucleon-nucleon production threshold in the heavy ion reactions $^{40}\mathrm{Ar}$+ $^{\mathrm{nat}}\mathrm{Ca}$, $^{86}\mathrm{Kr}$ + $^{\mathrm{nat}}\mathrm{Zr}$, and $^{197}\mathrm{Au}$+ $^{197}\mathrm{Au}$ at 1.0A GeV and also in $^{40}\mathrm{Ar}$+ $^{\mathrm{nat}}\mathrm{Ca}$ at 1.5A GeV. The measured transverse momentum distributions are compared to model calculations. The relative abundance of \ensuremath{\Delta}(1232) and N(1535) resonances excited in the collision is deduced. A comparison to pion data reveals scaling with the transverse mass of the emitted meson.

Published
1994
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9. Investigation of pion absorption in heavy-ion induced subthresholdπ0production

Author

A.L. Boonstra, Miriam Marqués, L. Sezac, T. Matulewicz, R. W. Novotny, B. Fornal, L. Freindl, W. F. Henning, M. Pfeiffer, J. S. Díaz, F. Lefevre, R.S. Simon, R.S. Mayer, V. Metag, E. Casal, W. Mittig, Yves Roland Schutz, R.W. Ostendorf, Barbara Ewa Erazmus, R. Holzmann, H. Dabrowski, D. Ardouin, W. Kühn, G. Martínez, H. Delagrange, F. D. Berg, J.L. Ferrero, Herbert Löhner, Z. Sujkowski, Facundo Ballester, H. W. Wilschut, C. Lebrun, R. Merrouch, H. Nifenecker, and L.B. Venema

Subjects
Physics, Nuclear reaction, Meson, 010308 nuclear & particles physics, Subthreshold conduction, Scattering, Nuclear Theory, Attenuation length, General Physics and Astronomy, Nuclear matter, 01 natural sciences, 7. Clean energy, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

We present results from an experimental study of reabsorption effects in subthreshold pi0 production in the reaction Xe-129 + Au-197 at 44 MeV/nucleon. Within the picture of pion generation in nucleon-nucleon scattering we deduce, from our data and from a comparison with the systematics of production cross sections available for lighter reaction systems, information on the pi0 absorption length in nuclear matter. For the pi0 kinetic-energy range congruent-to 5-100 MeV the energy-averaged lambda(abs) and its momentum dependence are obtained, and compared with optical-model calculations.

Published
1993
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10. In-mediumωmass from theγ+Nb→π0γ+Xreaction

Author

V. Metag, M. Ostrick, M. Kotulla, Ch. Schmidt, A. Ehmanns, V. Crede, M. Pfeiffer, D. Elsner, R. Ewald, R. Bogendorfer, R. W. Novotny, Ph. Hoffmeister, Yu. A. Beloglazov, R. Gregor, T. Szczepanek, Friedrich Klein, B. Schoch, J. C. S. Bacelar, H. Schmieden, D. E. Bayadilov, I. Fabry, A. Radkov, A. B. Gridnev, Mariana Nanova, G. Suft, S. Shende, Michael Fuchs, D. Trnka, J. Langheinrich, J. Lotz, O. Bartholomy, H. Dutz, U. Thoma, Frank Klein, J. Hossl, S. Schadmand, R. Varma, I. V. Lopatin, R. W. Gothe, D. Walther, Ch. Weinheimer, H. van Pee, E. Gutz, J. Junkersfeld, J. G. Messchendorp, T. Mertens, Herbert Löhner, C. Morales, Lalit Mohan Pant, M. Konrad, B. Kopf, I. Jaegle, Gisela Anton, Ch. Funke, I. Horn, S. Lugert, Eberhard Klempt, S. Höffgen, B. Krusche, R. Castelijns, K. Essig, A. Süle, Ankhi Roy, D. Menze, Ch. Wendel, V. V. Sumachev, and H. Kalinowsky

Subjects
Absolute magnitude, Physics, Nuclear and High Energy Physics, Particle physics, Photon, Meson, Electron, Sensitivity (control systems), Nuclear Experiment, Nuclear matter, Omega, Line (formation)
Abstract

Data on the photoproduction of $\ensuremath{\omega}$ mesons on nuclei have been reanalyzed in a search for in-medium modifications. The data were taken with the crystal barrel (CB)/two-arm photon spectrometer (TAPS) detector system at the ELectron Stretcher Anlage (ELSA) accelerator facility in Bonn. First results from the analysis of the data set were published by Trnka et al. [Phys. Rev. Lett. 94, 192303 (2005)], claiming a lowering of the $\ensuremath{\omega}$ mass in the nuclear medium by 14$%$ at normal nuclear matter density. The extracted $\ensuremath{\omega}$ line shape was found to be sensitive to the background subtraction. For this reason a reanalysis of the same data set has been initiated, and a new method has been developed to reduce the background and to determine the shape and absolute magnitude of the background directly from the data. Details of the reanalysis and of the background determination are described. The $\ensuremath{\omega}$ signal on the Nb target, extracted in the reanalysis, does not show a deviation from the corresponding line shape on a ${\mathrm{LH}}_{2}$ target, measured as reference. The earlier claim of an in-medium mass shift is thus not confirmed. The sensitivity of the $\ensuremath{\omega}$ line shape to different in-medium modification scenarios is discussed.

Published
2010
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11. Measurement of the beam asymmetryΣin the forward direction forγ⃗p→pπ0

Author

O. Bartholomy, V. A. Nikonov, S. Lugert, Eberhard Klempt, H. Schmieden, D. E. Bayadilov, T. Mertens, E. Gutz, A. B. Gridnev, Mariana Nanova, Herbert Löhner, D. Elsner, R. Castelijns, Yu. A. Beloglazov, H. van Pee, H. Kalinowsky, J. C. S. Bacelar, A. V. Sarantsev, N. Sparks, R. W. Novotny, Ph. Hoffmeister, B. Krusche, D. Menze, Friedrich Klein, S. Kammer, I. Jaegle, C. Funke, Ch. Schmidt, Ch. Wendel, B. Schoch, V. V. Sumachev, L. M. Pant, A. Roy, R. Bantes, S. Shende, D. V. Novinski, V. Sokhoyan, Volker Metag, R. Gregor, A. V. Anisovich, U. Thoma, J. G. Messchendorp, D. Walther, S. Schadmand, J. Junkersfeld, R. Ewald, I. V. Lopatin, Wolfgang Hillert, R. Beck, D. Trnka, M. Kotulla, T. Szczepanek, R. Varma, A. Süle, M. Ostrick, V. Crede, Frank Klein, A. Wilson, M. Pfeiffer, and Frank Frommberger

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Photon, Meson, media_common.quotation_subject, Hadron, Sigma, Elementary particle, Asymmetry, Nuclear physics, Pion, High Energy Physics::Experiment, Nuclear Experiment, Lepton, media_common
Abstract

Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector for photon energies between 0.92 and 1.68 GeV at the electron stretcher accelerator ELSA. The beam asymmetry Sigma has been extracted for 115 degrees > theta(c.m.) > 155 degrees of the pi(0) meson and for theta(c.m.) > 60 degrees. The new beam-asymmetry data cover the very forward region, which extend previously published data for the same reaction by our collaboration and improve the world database for photon energies above 1.5 GeV. The angular dependence of Sigma shows overall good agreement with the SAID parametrization.

Published
2010
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12. Emission patterns of neutral pions in40AMeV Ta+Au reactions

Author

R.W. Ostendorf, A. Kugler, Y. Schutz, G. Martínez-García, P. Tlustý, R. Turrisi, T. Matulewicz, H. Delagrange, V. Wagner, Krzysztof Piasecki, J. S. Díaz, F. Fernández, N. Yahlali, Herbert Löhner, David D'Enterria, and H. W. Wilschut

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Photon, Meson, 010308 nuclear & particles physics, Nuclear Theory, Hadron, Kinetic energy, 7. Clean energy, 01 natural sciences, Spectral line, Nuclear physics, Pion, 0103 physical sciences, Phenomenological model, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

Differential cross sections of neutral pions emitted in {sup 181}Ta+{sup 197}Au collisions at a beam energy of 39.5A MeV have been measured with the two-arm photon spectrometer (TAPS). The kinetic energy and transverse momentum spectra of neutral pions cannot be properly described in the framework of the thermal model, nor when the reabsorption of pions is accounted for in a phenomenological model. However, high energy and high momentum tails of the pion spectra can be well fitted through thermal distributions with unexpectedly soft temperature parameters below 10 MeV.

Published
2010
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13. Beam asymmetries in near-thresholdωphotoproduction off the proton

Author

V. Sokhoyan, Matthew Lang, M. Pfeiffer, D. Walther, A. Ehmanns, J. Junkersfeld, R. Varma, Ch. Weinheimer, S. Shende, Friedrich Klein, M. Ostrick, H. Kalinowsky, H. Dutz, Frank Klein, A. Roy, R. Beck, D. Elsner, D. Menze, V. Metag, E. Gutz, V. Crede, Ph. Hoffmeister, H. Schmieden, I. Jaegle, D. E. Bayadilov, S. Kammer, A. B. Gridnev, H. van Pee, Mariana Nanova, Ch. Wendel, V. Kleber, Ch. Funke, Yu. A. Beloglazov, R. Castelijns, A. Suele, V. V. Sumachev, A. V. Sarantsev, O. Bartholomy, M. Kotulla, K. Essig, M. Konrad, D. Trnka, R. Novotny, S. Hoeffgen, I. V. Lopatin, T. Mertens, A. V. Anisovich, U. Thoma, Herbert Löhner, B. Bantes, C. Morales, B. Schoch, A. Radkov, J. G. Messchendorp, I. Fabry, J. C. S. Bacelar, R. Gregor, R. Ewald, T. Szczepanek, M. Fuchs, V. A. Nikonov, I. Horn, S. Lugert, Eberhard Klempt, Ch. Schmidt, J. Lotz, D. V. Novinski, B. Krusche, L. M. Pant, Research unit Nuclear & Hadron Physics, and Publica

Subjects
TAPS, Physics, Nuclear and High Energy Physics, Photon, Proton, Meson, media_common.quotation_subject, photon, Nuclear Theory, Bremsstrahlung, Resonance, PHOTONS, MESONS, ETA, Omega, Asymmetry, Nuclear physics, Pion, SPECTROMETER, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, media_common
Abstract

The photoproduction of {omega} mesons off protons has been studied at the Bonn ELSA accelerator from threshold to E{sub {gamma}}=1700 MeV. Linearly polarized beams were produced via coherent bremsstrahlung. Large photon asymmetries in excess of 50% were obtained. For the first time the pion asymmetries associated with the {omega}{yields}{pi}{sup 0}{gamma} decay were measured and found close to zero. The asymmetries indicate s-channel resonance formation on top of t-channel exchange processes.

Published
2008
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14. Evidence for a Parity DoubletΔ(1920)P33andΔ(1940)D33fromγp→pπ0η

Author

R. Castelijns, D. Menze, J. Junkersfeld, J. Ernst, A. Ehmanns, B. Krusche, Sumachev, J. Hossl, M. Konrad, Herbert Löhner, Crede, B. Kopf, A. V. Anisovich, H. Schmieden, E. Gutz, O. Bartholomy, A. B. Gridnev, D. Walther, M. Ostrick, Metag, J. Lotz, D. V. Novinski, R. Bantes, Frank Klein, Gisela Anton, U. Thoma, V. A. Nikonov, R. W. Gothe, C. Funke, H. Flemming, B. Schoch, Yu. A. Beloglazov, A. V. Sarantsev, H. Kalinowsky, G. Suft, I. V. Lopatin, Messchendorp J, I. Horn, Eberhard Klempt, S. Höffgen, H. Matthäy, van Pee H, C.-H. Weinheimer, R. Beck, I. Fabry, Herbert Koch, R. Bogendorfer, T. Szczepanek, M. Fuchs, J. Langheinrich, A. Fosel, and Ch. Schmidt

Subjects
Delta, Quantum chromodynamics, Physics, Nuclear physics, Particle physics, Total angular momentum quantum number, Partial wave analysis, Quark model, Pi, General Physics and Astronomy, Parity (physics), Nuclear Experiment, Delta baryon
Abstract

Evidence is reported for the existence of a parity doublet of Delta resonances with total angular momentum J=3/2 from photoproduction of the p pi(0)eta final state. The two parity partners Delta(1920)P-33 and Delta(1940)D-33 make significant contributions to the reaction. Cascades of resonances into Delta(1232)eta, N(1535)pi, and Na-0(980) are clearly observed.

Published
2008
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15. Suppression of High-pTNeutral Pion Production in CentralPb+PbCollisions atsNN=17.3 GeVRelative top+Candp+PbCollisions

Author

K. Söderström, S. Pavliouk, C. Roy, H. Kalechofsky, H. Naef, A. Nianine, S. Bathe, V. S. Bhatia, K. Karadjev, Michal Sumbera, Y. P. Viyogi, P. Steinberg, Teodor Siemiarczuk, Joakim Nystrand, Sergey Fokin, S. P. Sorensen, T. H. Shah, T. Peitzmann, K. B. Bhalla, German Martinez, Peter M. Nilsson, M. R. Dutta Majumdar, V. Astakhov, M. J. Mora, L. Tykarski, A.S. Vodopianov, T. Mukhanova, Shunji Nishimura, A.L.S. Angelis, Frank Jm Geurts, A. Kugler, M. Rammler, MV Manzano Martin, Petr Nomokonov, B.N. Gus'kov, Sukalyan Chattopadhyay, R. Kamermans, Bedangadas Mohanty, R. Glasow, T. Bernier, V. Arefiev, J. Rak, T. C. Awes, Anand Kumar Dubey, K. Enosawa, Rashmi Raniwala, Christoph Blume, E. Stenlund, M. S. Ganti, Ivana Hrivnacova, D. P. Morrison, F. Retiere, H. Delagrange, G.S. Shabratova, H.H. Gutbrod, Gerrit Jan van Nieuwenhuizen, Basanta Kumar Nandi, S. Garpman, P. W. Stankus, Vladislav Manko, Sanjeev Singh Sambyal, O. P. Gavrishchuk, Herbert Löhner, H. A. Gustafsson, D. P. Mahapatra, P. Donni, D. Bucher, G. Stefanek, Yasuo Miake, A. Lebedev, G. R. Young, Hr Schmidt, Krzysztof Karpio, D. Y.-U. Peressounko, Zubayer Ahammed, L. Rosselet, S. K. Badyal, Agneta Oskarsson, G. Sood, Bikash Sinha, D. Mukhopadhyay, N. K. Rao, G. C. Mishra, R. Santo, Gunther Roland, L. Luquin, Klaus Johannes Reygers, T. K. Nayak, A. Maximov, Sudhir Raniwala, Mikhail Ippolitov, Sergey Nikolaev, J. M. Rubio, F. Plasil, I. Sibiriak, H. Büsching, M. Kurata, W. Pinganaud, V. Nikitine, T. Svensson, S. K. Nayak, B. W. Kolb, S. C. Phatak, I. Roufanov, S. Vörös, A. A. Vinogradov, B. Batiounia, P. Kulinich, Nikolai V Slavine, A. A. Tsvetkov, Bolek Wyslouch, E. C. v. d. Pijll, Martin Purschke, Madan M. Aggarwal, Susumu Sato, K. El Chenawi, N. v. Eijndhoven, V. Avdeitchikov, M. P. Decowski, I. Koutcheryaev, P.V.K.S. Baba, C. Baumann, I. Otterlund, Yves Roland Schutz, V.G. Antonenko, H. Schlagheck, I. Kosarev, T. K. Ghosh, D. Silvermyr, Vladimir Frolov, V. Petráček, and Lars Carlén

Subjects
Physics, Particle physics, Pion, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, 0103 physical sciences, Transverse momentum, General Physics and Astronomy, Production (computer science), Nuclear Experiment, 010306 general physics, 01 natural sciences
Abstract

Neutral pion transverse momentum spectra were measured in $p+\mathrm{C}$ and $p+\mathrm{Pb}$ collisions at $\sqrt{{s}_{NN}}=17.4\text{ }\text{ }\mathrm{GeV}$ at midrapidity ($2.3\ensuremath{\lesssim}{\ensuremath{\eta}}_{\mathrm{lab}}\ensuremath{\lesssim}3.0$) over the range $0.7\ensuremath{\lesssim}{p}_{T}\ensuremath{\lesssim}3.5\text{ }\text{ }\mathrm{GeV}/c$. The spectra are compared to ${\ensuremath{\pi}}^{0}$ spectra measured in $\mathrm{Pb}+\mathrm{Pb}$ collisions at $\sqrt{{s}_{NN}}=17.3\text{ }\text{ }\mathrm{GeV}$ in the same experiment. For a wide range of $\mathrm{Pb}+\mathrm{Pb}$ centralities (${N}_{\mathrm{part}}\ensuremath{\lesssim}300$), the yield of ${\ensuremath{\pi}}^{0}$'s with ${p}_{T}\ensuremath{\gtrsim}2\text{ }\text{ }\mathrm{GeV}/c$ is larger than or consistent with the $p+\mathrm{C}$ or $p+\mathrm{Pb}$ yields scaled with the number of nucleon-nucleon collisions (${N}_{\mathrm{coll}}$), while for central $\mathrm{Pb}+\mathrm{Pb}$ collisions with ${N}_{\mathrm{part}}\ensuremath{\gtrsim}350$, the ${\ensuremath{\pi}}^{0}$ yield is suppressed.

Published
2008
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16. Observation of In-Medium Modifications of theωMeson

Author

V. Crede, V. Metag, I. Fabry, Yu. A. Beloglazov, Lalit Mohan Pant, R. W. Gothe, S. Lugert, H. Dutz, J. Hossl, Eberhard Klempt, S. Höffgen, R. Varma, R. Castelijns, Fritz Klein, I. Horn, M. Ostrick, G. Suft, S. Shende, I. Jaegle, M. Kotulla, T. Mertens, R. Gregor, S. Schadmand, Herbert Löhner, A. Roy, Gisela Anton, O. Bartholomy, Ch. Schmidt, C. Morales, J. Lotz, D. Trnka, J. Langheinrich, H. Kalinowsky, D. Walther, T. Szczepanek, Frank Klein, K. Essig, A. Süle, E. Gutz, B. Kopf, B. Krusche, A. Radkov, A. Ehmanns, H. van Pee, M. Pfeiffer, Ch. Funke, D. Menze, D. Elsner, M. Konrad, H. Schmieden, D. E. Bayadilov, Ch. Wendel, A. B. Gridnev, Mariana Nanova, V. V. Sumachev, U. Thoma, R. W. Novotny, Ph. Hoffmeister, J. C. S. Bacelar, B. Schoch, J. Junkersfeld, R. Ewald, R. Bogendorfer, J. G. Messchendorp, Michael Fuchs, I. V. Lopatin, and Ch. Weinheimer

Subjects
Physics, Particle physics, Meson, Nuclear Theory, Hadron, General Physics and Astronomy, Omega baryon, Omega, Baryon, Nuclear physics, Particle decay, Pion, High Energy Physics::Experiment, Nuclear Experiment, Nuclear density
Abstract

The photoproduction of omega mesons on nuclei has been investigated using the Crystal Barrel/TAPS experiment at the ELSA tagged photon facility in Bonn. The aim is to study possible in-medium modifications of the omega meson via the reaction gamma+A

Published
2005
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17. Neutral-PionPhotoproduction off Protons in the Energy Range0.3 GeV<Eγ<3 GeV

Author

H. van Pee, M. Konrad, R. Bantes, Gisela Anton, H. Flemming, R. Joosten, M. Ostrick, Herbert Löhner, J. Langheinrich, D. V. Novinski, H. Kalinowsky, Ch. Weinheimer, G. Suft, R. Castelijns, E. Gutz, T. Szczepanek, J. Hossl, R. W. Gothe, A. Radkov, Yu. A. Beloglazov, D. Menze, A. Ehmanns, A. V. Sarantsev, V. Crede, H. Matthäy, B. Krusche, J. Reinnarth, J. Ernst, S. Schadmand, H. Freiesleben, B. Schoch, Frank Klein, C. Morales, A. V. Anisovich, V. V. Sumachev, U. Thoma, R. Bogendorfer, Michael Fuchs, J. Lotz, I. V. Lopatin, H. Schmieden, J. Junkersfeld, J. G. Messchendorp, A. B. Gridnev, D. Walther, I. Fabry, B. Kopf, Herbert Koch, A. Fosel, Ch. Schmidt, Ch. Funke, O. Bartholomy, I. Horn, Eberhard Klempt, and S. Höffgen

Subjects
Nuclear physics, Physics, Range (particle radiation), Particle physics, Pion, Photon, Proton, Partial wave analysis, Solid angle, General Physics and Astronomy, Resonance, Intermediate state
Abstract

Single pi(0) photoproduction has been studied with the CB-ELSA experiment at Bonn using tagged photon energies between 0.3 and 3.0 GeV. The experimental setup covers a very large solid angle of similar to98% of 4pi. Differential cross sections dsigma/dOmega have been measured. Complicated structures in the angular distributions indicate a variety of different resonances being produced in the s channel intermediate state gammap-->N(*)(Delta(*))-->ppi(0). A combined analysis including the data presented in this letter along with other data sets reveals contributions from known resonances and evidence for a new resonance N(2070)D(15).

Published
2005
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18. PhotoproductionofηMesonsoff Protons for0.75 GeV<Eγ<3 GeV

Author

H. Flemming, M. Konrad, V. Crede, Gisela Anton, B. Kopf, D. V. Novinski, C. Morales, D. Walther, H. van Pee, U. Thoma, H. Schmieden, Ch. Funke, A. B. Gridnev, H. Kalinowsky, A. V. Anisovich, J. Junkersfeld, R. Castelijns, D. Menze, R. Joosten, A. Fosel, Ch. Schmidt, J. Langheinrich, E. Gutz, R. Bantes, S. Schadmand, A. Radkov, O. Bartholomy, M. Ostrick, A. Ehmanns, H. Matthäy, I. Fabry, Herbert Koch, J. G. Messchendorp, Frank Klein, V. V. Sumachev, Yu. A. Beloglazov, A. V. Sarantsev, J. Hosl, B. Krusche, J. Reinnarth, B. Schoch, Michael Fuchs, R. Bogendorfer, T. Szczepanek, Herbert Löhner, I. V. Lopatin, G. Suft, Ch. Weinheimer, I. Horn, Eberhard Klempt, S. Höffgen, J. Ernst, H. Freiesleben, J. Lotz, and R. W. Gothe

Subjects
Physics, Particle physics, Range (particle radiation), Photon, Meson production, Proton, Meson, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, Resonance, Nuclear physics, Angular distribution, High Energy Physics::Experiment, Nuclear Experiment, Nucleon
Abstract

Total and differential cross sections for the reaction p(gamma,eta)p have been measured for photon energies in the range from 750 MeV to 3 GeV. The low-energy data are dominated by the S-11 wave which has two poles in the energy region below 2 GeV. Eleven nucleon resonances are observed in their decay into peta. At medium energies we find evidence for a new resonance N(2070)D-15 with (M,Gamma)=(2068+/-22, 295+/-40) MeV. At gamma energies above 1.5 GeV, a strong peak in the forward direction develops, signaling the exchange of vector mesons in the t channel.

Published
2005
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19. Interferometry of Direct Photons in CentralPb208+Pb208Collisions at158A GeV

Author

Krzysztof Karpio, K. Söderström, Jan Rak, Pål Nilsson, P. Kulinich, G. R. Young, Hans Rudolf Schmidt, Bedangadas Mohanty, R. Glasow, Nikolai V Slavine, Teodor Siemiarczuk, A.L. Lebedev, Evert Stenlund, Joakim Nystrand, Shunji Nishimura, A. K. Dubey, T. Bernier, V. Nikitine, T. Peitzmann, T. Svensson, H. Schlagheck, T. H. Shah, H. Kalechofsky, I. Roufanov, Madan M. Aggarwal, S. Garpman, H. Naef, Susumu Sato, A. Nianine, A.L.S. Angelis, S. K. Nayak, A.S. Vodopianov, V. S. Bhatia, Zubayer Ahammed, Vladimir Frolov, B. W. Kolb, Klaus Johannes Reygers, Y. P. Viyogi, G. C. Mishra, M. R. Dutta Majumdar, Lars Carlén, Sanjeev Singh Sambyal, S. K. Badyal, D. P. Mahapatra, B. Guskov, K. El Chenawi, V. Astakhov, C. Roy, Bikash Sinha, F. Retiere, T. V. Moukhanova, Y. Schutz, I. Hrivnacova, A. A. Vinogradov, S. Vörös, N. v. Eijndhoven, S. P. Sorensen, I. Koutcheryaev, F. J M Geurts, P.V.K.S. Baba, V. Arefiev, Anders Oskarsson, H. H. Gutbrod, V.G. Antonenko, I. Sibiriak, Gerrit Jan van Nieuwenhuizen, B. Batiounia, D. Peressounko, V. Avdeitchikov, Ingvar Otterlund, M. Kurata, Yasuo Miake, C. Blume, P. Donni, A. A. Tsvetkov, D. Silvermyr, Bolek Wyslouch, Sukalyan Chattopadhyay, M. S. Ganti, Hans-Åke Gustafsson, O. P. Gavrishchuk, G. Stefanek, L. Luquin, E. C. v. d. Pijll, T. C. Awes, S. C. Phatak, M. P. Decowski, D. P. Morrison, W. Pinganaud, A. Maximov, K. Karadjev, Sergey Nikolaev, Sergey Fokin, K. B. Bhalla, M. J. Mora, Mikhail Ippolitov, K. Enosawa, T. K. Ghosh, Petr Nomokonov, Rashmi Raniwala, P. W. Stankus, Herbert Löhner, N. K. Rao, L. Rosselet, V. Petracek, H. Delagrange, Vladislav Manko, S. Bathe, Michal Sumbera, L. Tykarski, Sudhir Raniwala, J. M. Rubio, D. S. Mukhopadhyay, G. Martínez, Gunther Roland, F. Plasil, H. Büsching, G. Sood, B. K. Nandi, R. Santo, A. Kugler, M. L. Purschke, T. K. Nayak, MV Manzano Martin, P. Steinberg, I. Kosarev, G.S. Shabratova, and D. Bucher

Subjects
Physics, Particle physics, Photon, 010308 nuclear & particles physics, General Physics and Astronomy, Plasma, Invariant (physics), 01 natural sciences, Photon yield, Central region, Nuclear physics, Interferometry, 0103 physical sciences, Nuclear Experiment, 010306 general physics
Abstract

Two-particle correlations of direct photons were measured in central 208Pb+208Pb collisions at 158A GeV. The invariant interferometric radii were extracted for 100

Published
2004
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20. DirectK-shell ionization probabilities in 30-MeV/u Ne- and 8.3-MeV/u C-induced reactions near zero impact parameter

Author

A.M. van den Berg, H. W. Wilschut, B. Davids, A. van der Woude, M.A. de Huu, M.D. Hunyadi, V. L. Kravchuk, F. Fleurot, Herbert Löhner, Research unit Astroparticle Physics, and Research unit Nuclear & Hadron Physics

Subjects
Physics, Nuclear Theory, Z ELEMENTS, Zero (complex analysis), Electron shell, chemistry.chemical_element, Semiclassical physics, Electron, Atomic and Molecular Physics, and Optics, PROJECTILES, Samarium, chemistry, Ionization, Impact parameter, Atomic physics, Nuclear Experiment, X ray spectra
Abstract

Direct K-shell ionization probabilities were measured in coincidence with elastically scattered particles in 30-MeV/u $\mathrm{Ne}+\mathrm{Sn},$ Tb, Pb, Th and 8.3-MeV/u $\mathrm{C}+\mathrm{Zr},$ Ag, Sn, Sm, Au, Pb, Th reactions. Experimental data were compared with calculations in the semiclassical approximation. The transitional behavior at the reduced velocity ${\ensuremath{\xi}}_{K}\ensuremath{\approx}1,$ where the projectile velocity approaches the velocity of the K-shell electrons, is discussed.

Published
2003
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21. Centrality dependence of charged-neutral particle fluctuations in158AGeV208Pb+208Pbcollisions

Author

F. J M Geurts, V.G. Antonenko, Krzysztof Karpio, C. Roy, I. G. Sibiriak, H. Schlagheck, T. Bernier, Jan Rak, F. Plasil, H. Büsching, S. P. Sorensen, I. Otterlund, MV Manzano Martin, T. H. Shah, V. Arefiev, Peter M. Nilsson, K. Söderström, G. Sood, S. Garpman, B. K. Nandi, T. Mukhanova, A. A. Vinogradov, H. Kalechofsky, R. Santo, H. A. Gustafsson, V. Frolov, H. H. Gutbrod, Shunji Nishimura, Sanjeev Singh Sambyal, K. Enosawa, H. Naef, Yasuo Miake, Teodor Siemiarczuk, A. Nianine, Sukalyan Chattopadhyay, A. K. Dubey, B. Batiounia, Joakim Nystrand, T. K. Ghosh, M. P. Decowski, M. S. Ganti, L. Rosselet, D. P. Morrison, W. Pinganaud, V. S. Bhatia, A. Kugler, K. Reygers, David Olle Rickard Silvermyr, Petr Nomokonov, I. Koutcheryaev, P.V.K.S. Baba, Rashmi Raniwala, I. Roufanov, T. K. Nayak, P. Kulinich, D. P. Mahapatra, Agneta Oskarsson, N. v. Eijndhoven, Nikolai V Slavine, A. Maximov, Zubayer Ahammed, E. C. v. d. Pijll, G. R. Young, L. Luquin, A.L.S. Angelis, D. S. Mukhopadhyay, N. K. Rao, M. L. Purschke, S. K. Badyal, Gunther Roland, K. B. Bhalla, M. J. Mora, B. Guskov, Bikash Sinha, H. Delagrange, A.S. Vodopianov, T. Peitzmann, Sudhir Raniwala, M. R. Dutta Majumdar, I. Hrivnacova, J. M. Rubio, V. Avdeitchikov, K. Karadjev, S. Vörös, Susumu Sato, V. Astakhov, Sergey Fokin, P. Steinberg, F. Retiere, Sergey Nikolaev, I. Kosarev, C. Blume, P. W. Stankus, P. Donni, A. A. Tsvetkov, Herbert Löhner, O. P. Gavrishchuk, Bolek Wyslouch, Madan M. Aggarwal, H. R. Schmidt, M. Kurata, S. K. Nayak, G. Martínez, B. W. Kolb, K. El Chenawi, G. C. Mishra, G.S. Shabratova, D. Bucher, V. Nikitine, T. Svensson, Gerrit Jan van Nieuwenhuizen, E. Stenlund, D. Peressounko, Y. Schutz, Y. P. Viyogi, Lars Carlén, G. Stefanek, T. C. Awes, Mikhail Ippolitov, Bedangadas Mohanty, R. Glasow, A.L. Lebedev, S. Bathe, Michal Sumbera, L. Tykarski, V. Petracek, and Vladislav Manko

Subjects
Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Photon, 010308 nuclear & particles physics, Multiplicity (mathematics), 01 natural sciences, Molecular physics, Charged particle, Nuclear physics, Phase space, 0103 physical sciences, 010306 general physics, Neutral particle
Abstract

Results on the study of localized fluctuations in the multiplicity of charged particles and photons produced in 158A GeV/c Pb+Pb collisions are presented for varying centralities. The charged versus neutral particle multiplicity correlations in common phase space regions of varying azimuthal sizes are analyzed by two different methods. Various types of mixed events are constructed to probe fluctuations arising from different sources. The measured results are compared to those from simulations and from mixed events. The comparison indicates the presence of nonstatistical fluctuations in both the charged particle and photon multiplicities in limited azimuthal regions. However, no correlated charged-neutral fluctuations, a possible signature of formation of disoriented chiral condensates, are observed. An upper limit on the production of disoriented chiral condensates is set.

Published
2003
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22. Exclusive Measurement of Coherent Proton-Deuteron Bremsstrahlung

Author

Herbert Löhner, Nasser Kalantar-Nayestanaki, J. C. S. Bacelar, Olaf Scholten, M. Hoefman, J. G. Messchendorp, V. Wagner, H. W. Wilschut, R.S. Simon, M. Volkerts, S. Schadmand, Mohsen Harakeh, R.W. Ostendorf, H. Huisman, M. J. van Goethem, and Research unit Nuclear & Hadron Physics

Subjects
Physics, Proton, ENERGIES, Nuclear Theory, Bremsstrahlung, NUCLEON-NUCLEON BREMSSTRAHLUNG, General Physics and Astronomy, Nuclear physics, Deuterium, Atomic physics, EXCHANGE, Nuclear Experiment, PION-PRODUCTION THRESHOLD, Beam energy, SYSTEM
Abstract

For the first time a high-precision proton-deuteron bremsstrahlung experiment has been performed in which all the different exit channels have been distinguished separately. High-precision cross sections and analyzing powers in one of the outgoing channels, namely, the coherent bremsstrahlung with a proton and a deuteron in the final state, are presented at 190 MeV incoming proton beam energy and are compared to calculations based on the low-energy theorem. The results of the calculations vary considerably calling for a fully microscopic calculation. However, using a recipe including the initial- and final-state interactions, the predictions come close to the data.

Published
2003
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23. One-, two-, and three-particle distributions from158AGeV/ccentral Pb+Pb collisions

Author

M. L. Purschke, P. Steinberg, I. Sibiriak, V. Petracek, I. Kosarev, Shunji Nishimura, Vladislav Manko, S. K. Nayak, E. Stenlund, K. Söderström, T. H. Shah, Yasuo Miake, G. Sood, Sukalyan Chattopadhyay, M. S. Ganti, A.L.S. Angelis, G. Stefanek, T. Mukhanova, K. Enosawa, A. A. Vinogradov, T. C. Awes, T. K. Ghosh, L. Rosselet, E. C. v. d. Pijll, K. Karadjev, Sergey Fokin, M. P. Decowski, G. Martínez, D. P. Mahapatra, B. Batiounia, R. Santo, Hans Rudolf Schmidt, A.S. Vodopianov, Joakim Nystrand, Gerrit Jan van Nieuwenhuizen, Agneta Oskarsson, D. Peressounko, S. Bathe, H. A. Gustafsson, A. Maximov, G.S. Shabratova, K. B. Bhalla, M. R. Dutta Majumdar, V. Astakhov, P. Kulinich, M. J. Mora, S. P. Sorensen, Michal Sumbera, V. Arefiev, A. Kugler, Klaus Johannes Reygers, G. R. Young, Peter M. Nilsson, P. Donni, H. H. Gutbrod, Nikolai V Slavine, Sergey Nikolaev, C. Blume, Krzysztof Karpio, H. Kalechofsky, H. Naef, V. Frolov, T. Bernier, Jan Rak, L. Tykarski, P. W. Stankus, A. Nianine, O. P. Gavrishchuk, S. Garpman, T. K. Nayak, Herbert Löhner, V. S. Bhatia, S. K. Badyal, D. Bucher, D. P. Morrison, I. Roufanov, D. S. Mukhopadhyay, Gunther Roland, MV Manzano Martin, B. Guskov, Bikash Sinha, F. J M Geurts, V.G. Antonenko, Bedangadas Mohanty, G. C. Mishra, R. Kamermans, H. Schlagheck, S. Vörös, R. Glasow, Teodor Siemiarczuk, David Olle Rickard Silvermyr, I. Hrivnacova, M. Kurata, Y. Schutz, A.L. Lebedev, Lars Carlén, Mikhail Ippolitov, V. Nikitine, Y. P. Viyogi, T. Svensson, H. Delagrange, Sudhir Raniwala, J. M. Rubio, Petr Nomokonov, Rashmi Raniwala, N. K. Rao, F. Plasil, H. Büsching, B. K. Nandi, Madan M. Aggarwal, B. W. Kolb, K. El Chenawi, N. v. Eijndhoven, V. Avdeitchikov, Susumu Sato, Sanjeev Singh Sambyal, A. A. Tsvetkov, Bolek Wyslouch, T. Peitzmann, I. Otterlund, I. Koutcheryaev, and P.V.K.S. Baba

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Nuclear Theory, Hadron, Elementary particle, Nuclear matter, 01 natural sciences, Nuclear physics, Pion, Phase space, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Boson
Abstract

Several hadronic observables have been studied in central 158A GeV Pb+Pb collisions using data measured by the WA98 experiment at CERN: single pi(-) and K- production, as well as two- and three-pion interferometry. The Wiedemann-Heinz hydrodynamical model has been fitted to the pion spectrum, giving an estimate of the temperature and transverse flow velocity. Bose-Einstein correlations between two identified pi(-) have been analyzed as a function of k(T), using two different parametrizations. The results indicate that the source does not have a strictly boost invariant expansion or spend time in a long-lived intermediate phase. A comparison between data and a hydrodynamical based simulation shows very good agreement for the radii parameters as a function of k(T). The pion phase-space density at freeze-out has been measured, and agrees well with the Tomasik-Heinz model. A large pion chemical potential close to the condensation limit of m(pi) seems to be excluded. The three-pion Bose-Einstein interferometry shows a substantial contribution of the genuine three-pion correlation, but not quite as large as expected for a fully chaotic and symmetric source.

Published
2003
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24. Event-by-event fluctuations in particle multiplicities and transverse energy produced in158A GeVPb+Pb collisions

Author

C. Blume, Petr Nomokonov, O. P. Gavrishchuk, S. Nikolaev, Rashmi Raniwala, A.S. Vodopianov, I. Sibiriak, G. Sood, H. Kalechofsky, Teodor Siemiarczuk, K. Karadjev, Madan M. Aggarwal, R. Santo, H. Naef, A. Nianine, F. J M Geurts, Sergey Fokin, B.N. Gus'kov, C. Roy, G. Martínez, V.G. Antonenko, T. K. Nayak, N. K. Rao, B. W. Kolb, K. El Chenawi, L. Rosselet, V. S. Bhatia, H. Schlagheck, I. Kosarev, A.L.S. Angelis, Agneta Oskarsson, M. L. Purschke, Krzysztof Karpio, S. Garpman, T. H. Shah, P. Steinberg, N. v. Eijndhoven, D. Y.-U. Peressounko, Jan Rak, H. A. Gustafsson, Vladimir Frolov, Yasuo Miake, Shunji Nishimura, Klaus Johannes Reygers, G.S. Shabratova, Lars Carlén, David Olle Rickard Silvermyr, V. Avdeitchikov, Susumu Sato, M. P. Decowski, I. Hrivnacova, Hans Rudolf Schmidt, A. A. Vinogradov, P. Donni, T. Mukhanova, G. C. Mishra, T. Peitzmann, Sukalyan Chattopadhyay, Sudhir Raniwala, B. Batiounia, M. S. Ganti, D. Bucher, Sanjeev Singh Sambyal, J. M. Rubio, H. Delagrange, K. Enosawa, T. Bernier, K. Söderström, P. Kulinich, M. Kurata, Nikolai V Slavine, T. K. Ghosh, F. Plasil, E. C. v. d. Pijll, Gunther Roland, H. Büsching, L. Luquin, D. P. Mahapatra, I. Otterlund, MV Manzano Martin, I. Koutcheryaev, P.V.K.S. Baba, B. K. Nandi, Joakim Nystrand, D. P. Morrison, W. Pinganaud, G. R. Young, A. A. Tsvetkov, K. B. Bhalla, Bolek Wyslouch, M. J. Mora, P. W. Stankus, Herbert Löhner, A. K. Dubey, F. Retiere, A. Maximov, G. Stefanek, Zubayer Ahammed, S. K. Badyal, Bikash Sinha, S. P. Sorensen, Peter M. Nilsson, A. Kugler, Y. P. Viyogi, S. K. Nayak, Mikhail Ippolitov, M. R. Dutta Majumdar, V. Arefiev, V. Astakhov, T. C. Awes, Gerrit Jan van Nieuwenhuizen, I. Roufanov, S. Vörös, S. Bathe, Michal Sumbera, S. C. Phatak, D. S. Mukhopadhyay, L. Tykarski, Bedangadas Mohanty, R. Glasow, A.L. Lebedev, V. Petracek, Vladislav Manko, V. Nikitine, T. Svensson, H. H. Gutbrod, E. Stenlund, and Y. Schutz

Subjects
Quantum chromodynamics, Nuclear physics, Physics, Nuclear and High Energy Physics, Phase transition, Transverse plane, Particle physics, Photon, Quark–gluon plasma, Multiplicity (mathematics), Charged particle, Event generator
Abstract

Event-by-event fluctuations in the multiplicities of charged particles and photons, and the total transverse energy in 158A GeV Pb+Pb collisions are studied for a wide range of centralities. For narrow centrality bins the multiplicity and transverse energy distributions are found to be near perfect Gaussians. The effect of detector acceptance on the multiplicity fluctuations has been studied and demonstrated to follow statistical considerations. The centrality dependence of the charged particle multiplicity fluctuations in the measured data has been found to agree reasonably well with those obtained from a participant model. However, for photons the multiplicity fluctuations have been found to be lower compared to those obtained from a participant model. The multiplicity and transverse energy fluctuations have also been compared to those obtained from the VENUS event generator.

Published
2002
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25. Erratum: Centrality Dependence of Neutral Pion Production in158AGeVP208b+P208bCollisions [Phys. Rev. Lett. 81, 4087 (1998)]

Author

Jan Rak, S. Pavliouk, M. Kurata, Gunther Roland, Zubayer Ahammed, P. Steinberg, K. Söderström, S. K. Badyal, L. Barabach, D. P. Morrison, Tatsuya Chujo, Shunji Nishimura, E.-M. Bohne, M. D. Trivedi, Bikash Sinha, W. Pinanaud, I. Otterlund, P. Kulinich, Nikolai V Slavine, A.L.S. Angelis, B. W. Kolb, R. Cherbatchev, K. Enosawa, S. Kato, I. Roufanov, P. Foka, G. R. Young, A.S. Vodopianov, P. Donni, Joakim Nystrand, P. W. Stankus, V. Djordjadze, Herbert Löhner, Hr Schmidt, Y.Y. Lee, I. Koutcheryaev, V. Nikitine, T. Svensson, K. Karadjev, R. Higuchi, V. S. Ramamurthy, Sergey Fokin, R. Glasow, D. P. Mahapatra, Petr Nomokonov, P.V.K.S. Baba, C. Roy, A. Lebedev, Hyun-Chul Kim, L. Rosselet, V. Myalkovski, Rashmi Raniwala, S. Vörös, H. Kalechofsky, K. B. Bhalla, G. C. Mishra, Z.K. Böröcz, Teodor Siemiarczuk, H. Naef, O. P. Gavrishchuk, A. Nianine, Ashim Das, R. K. Bock, G. Stefanek, Frank Jm Geurts, MV Manzano Martin, A. Baldine, V. S. Bhatia, D. Mukhopadhyay, T. Krümpel, N. K. Rao, N. v. Eijndhoven, A. A. Vinogradov, C. Twenhöfel, I. Sibiriak, S. Bathe, D. Mikhalev, F. Plasil, S. P. Sorensen, S. Neumaier, H. Büsching, A. Parfenov, A. Maximov, S. Garpman, S. K. Nayak, D. Stüken, Peter M. Nilsson, G.S. Shabratova, R. Mehdiyev, B. Batiounia, I. Langbein, Michal Sumbera, H. A. Gustafsson, A. Claussen, G. Mgebrichvili, E. Stenlund, A. Kugler, B.N. Gus'kov, A. Agnihotri, Sergey Nikolaev, S. Eliseev, Christoph Blume, Susumu Sato, Basanta Kumar Nandi, N. Solomey, D. Bucher, K. Yagi, Agneta Oskarsson, Yasuo Miake, R. Kamermans, Ivana Hrivnacova, B. Raeven, Sudhir Raniwala, S. Kees, V. Avdeitchikov, J. Urbahn, J. M. Rubio, Klaus Johannes Reygers, T. Bernier, Mikhail Ippolitov, L. Tykarski, A. A. Tsvetkov, Sukalyan Chattopadhyay, M. P. Decowski, M. S. Ganti, Hiroyuki Sako, Bolek Wyslouch, A. Buijs, R. Santo, L. Luquin, Y. Miyamoto, I. Doubovik, Y. Yokota, T. K. Nayak, Martin Purschke, Sanjeev Singh Sambyal, Vladislav Manko, H.H. Gutbrod, Shiv K. Gupta, K. Kurita, M. R. Dutta Majumdar, David Olle Rickard Silvermyr, V. Astakhov, T. Peitzmann, C. Barlag, V. Chalyshev, Felix E. Obenshain, M. Pachr, F. Retiere, Madan M. Aggarwal, K. El Chenawi, Kh Kampert, N.A. Kuzmin, H. Schlagheck, I. Kosarev, T. K. Ghosh, V. Arefiev, T. C. Awes, Gerrit Jan van Nieuwenhuizen, Vladimir Frolov, Y. P. Viyogi, V. Petráček, Lars Carlén, V.G. Antonenko, and Krzysztof Karpio

Subjects
Physics, Nuclear physics, Particle physics, Pion, General Physics and Astronomy, Centrality
Published
2000
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26. First Observation of the Coulomb-Excited Double Giant Dipole Resonance inPb208via Double-γDecay

Author

M. Pfeiffer, M. Notheisen, F. D. Berg, W. Kühn, K. D. Hildenbrand, R.S. Simon, K. Teh, O. Schwalb, J. P. Wessels, V. Metag, L.B. Venema, A. Gobbi, P. Paul, N. Herrmann, Herbert Löhner, T. Wienold, J. Ritman, J. Mösner, and R. W. Novotny

Subjects
Nuclear reaction, Physics, Nuclear Theory, Gamma ray, General Physics and Astronomy, Resonance, Coulomb excitation, Photon energy, Nuclear physics, Dipole, Giant resonance, Excited state, Coulomb, Atomic physics, Nuclear Experiment, Energy (signal processing)
Abstract

The photon decay of the relativistic Coulomb excitation of the single and double giant dipole resonance (GDR) in the target has been observed in the system 1A GeV $^{209}\mathrm{Bi}$ on $^{208}\mathrm{Pb}$. For peripheral events which are dominated by relativistic Coulomb excitation, a large Lorentzian structure in the photon energy spectrum is peaked at 13.3\ifmmode\pm\else\textpm\fi{}0.1 MeV with a width of 4.1\ifmmode\pm\else\textpm\fi{}0.1 MeV, corresponding to the single GDR in the $^{208}\mathrm{Pb}$ target. The sum energy of coincident \ensuremath{\gamma}-\ensuremath{\gamma} pairs shows a broad feature at 25.6\ifmmode\pm\else\textpm\fi{}0.9 MeV with a Lorentzian width of 5.8\ifmmode\pm\else\textpm\fi{}1.1 MeV, which we assign to the double GDR observed via the two-\ensuremath{\gamma} decay channel.

Published
1993
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27. Freezeout Density in Relativistic Nuclear Collisions Measured by Proton-Proton Correlations

Author

H. Riedesel, T. Renner, H.A. Gustafsson, B. W. Kolb, A. I. Warwick, B. Ludewigt, A. M. Poskanzer, F. Weik, H. H. Wieman, H. G. Ritter, H.H. Gutbrod, and Herbert Löhner

Subjects
Physics, Nuclear reaction, Proton, Nuclear Theory, Hadron, General Physics and Astronomy, Elementary particle, Nuclear matter, Nuclear physics, Baryon, Physics::Accelerator Physics, Atomic physics, Multiplicity (chemistry), Nuclear Experiment, Nucleon
Abstract

Proton-proton correlations were measured with the ''Plastic Ball'' detector for two systems, Ca + Ca and Nb + Nb, at 400 MeV/nucleon as a function of proton multiplicity. The source-size radii extracted from these measurements were found to have a cube-root dependence on the proton multiplicity of the event. The deduced freezeout density, the density at which collisions between fragments cease, was found to be about 25% of normal nuclear matter density.

Published
1984
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