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1. Azimuthal single- and double-spin asymmetries in semi-inclusive deep-inelastic lepton scattering by transversely polarized protons

Author: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Bacchetta, S. Belostotski, V. Bryzgalov, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, W. Deconinck, R. De Leo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, G. Elbakian, F. Ellinghaus, A. Fantoni, L. Felawka, G. Gavrilov, V. Gharibyan, D. Hasch, Y. Holler, A. Ivanilov, H. E. Jackson, S. Joosten, R. Kaiser, G. Karyan, E. Kinney, A. Kisselev, V. Kozlov, P. Kravchenko, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, W. Lorenzon, S. I. Manaenkov, B. Marianski, H. Marukyan, Y. Miyachi, A. Movsisyan, V. Muccifora, Y. Naryshkin, A. Nass, G. Nazaryan, W.-D. Nowak, L. L. Pappalardo, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, A. Schäfer, G. Schnell, B. Seitz, T.-A. Shibata, V. Shutov, M. Statera, A. Terkulov, M. Tytgat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, I. Vilardi, S. Yaschenko, D. Zeiler, B. Zihlmann, and P. Zupranski
Subjects: Fixed target experiments, Polarization, QCD, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Abstract A comprehensive set of azimuthal single-spin and double-spin asymmetries in semi-inclusive leptoproduction of pions, charged kaons, protons, and antiprotons from transversely polarized protons is presented. These asymmetries include the previously published HERMES results on Collins and Sivers asymmetries, the analysis of which has been extended to include protons and antiprotons and also to an extraction in a three-dimensional kinematic binning and enlarged phase space. They are complemented by corresponding results for the remaining four single-spin and four double-spin asymmetries allowed in the one-photon-exchange approximation of the semi-inclusive deep-inelastic scattering process for target-polarization orientation perpendicular to the direction of the incoming lepton beam. Among those results, significant non-vanishing cos (ϕ−ϕ S ) modulations provide evidence for a sizable worm-gear (II) distribution, g 1 T q x p T 2 $$ {g}_{1\mathrm{T}}^q\left(x,{\mathrm{p}}_T^2\right) $$ . Most of the other modulations are found to be consistent with zero with the notable exception of large sin (ϕ S ) modulations for charged pions and K +.
Published: 2020
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2. Ratios of helicity amplitudes for exclusive $$\rho ^0$$ ρ 0 electroproduction on transversely polarized protons

Author: A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, S. Belostotski, H. P. Blok, A. Borissov, V. Bryzgalov, G. P. Capitani, G. Ciullo, M. Contalbrigo, W. Deconinck, R. De Leo, E. De Sanctis, M. Düren, G. Elbakian, F. Ellinghaus, L. Felawka, S. Frullani, F. Garibaldi, G. Gavrilov, V. Gharibyan, S. V. Goloskokov, Y. Holler, A. Ivanilov, H. E. Jackson, S. Joosten, R. Kaiser, G. Karyan, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, P. Kroll, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, W. Lorenzon, S. I. Manaenkov, B. Marianski, H. Marukyan, Y. Miyachi, A. Movsisyan, V. Muccifora, A. Nass, W.-D. Nowak, L. L. Pappalardo, A. Petrosyan, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, D. Ryckbosch, Y. Salomatin, A. Schäfer, G. Schnell, B. Seitz, T.-A. Shibata, V. Shutov, M. Statera, A. Terkulov, R. Truty, A. Trzcinski, M. Tytgat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Yaschenko, B. Zihlmann, and P. Zupranski
Subjects: Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Abstract Exclusive $$\rho ^0$$ ρ 0 -meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in the kinematic region 1.0 GeV $$^2
Published: 2017
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3. Beam-helicity asymmetries for single-hadron production in semi-inclusive deep-inelastic scattering from unpolarized hydrogen and deuterium targets

Author: A. Airapetian, N. Akopov, Z. Akopov, E.C. Aschenauer, W. Augustyniak, S. Belostotski, H.P. Blok, V. Bryzgalov, G.P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, W. Deconinck, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, G. Elbakian, F. Ellinghaus, A. Fantoni, L. Felawka, G. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, A. Hillenbrand, Y. Holler, A. Ivanilov, H.E. Jackson, S. Joosten, R. Kaiser, G. Karyan, E. Kinney, A. Kisselev, V. Korotkov, V. Kozlov, P. Kravchenko, L. Lagamba, L. Lapikás, I. Lehmann, P. Lenisa, W. Lorenzon, S.I. Manaenkov, B. Marianski, H. Marukyan, A. Movsisyan, V. Muccifora, A. Nass, G. Nazaryan, W.-D. Nowak, L.L. Pappalardo, A.R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, D. Ryckbosch, G. Schnell, B. Seitz, T.-A. Shibata, V. Shutov, M. Statera, A. Terkulov, A. Trzcinski, M. Tytgat, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, I. Vilardi, C. Vogel, S. Yaschenko, V. Zagrebelnyy, D. Zeiler, B. Zihlmann, and P. Zupranski
Subjects: Physics, QC1-999
Abstract: A measurement of beam-helicity asymmetries for single-hadron production in deep-inelastic scattering is presented. Data from the scattering of 27.6 GeV electrons and positrons off gaseous hydrogen and deuterium targets were collected by the HERMES experiment. The asymmetries are presented separately as a function of the Bjorken scaling variable, the hadron transverse momentum, and the fractional energy for charged pions and kaons as well as for protons and anti-protons. These asymmetries are also presented as a function of the three aforementioned kinematic variables simultaneously. Keywords: Nucleon structure, Beam-helicity asymmetries, Deep-inelastic scattering, Twist-3, Transverse-momentum dependence
Published: 2019
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4. Ratios of helicity amplitudes for exclusive ρ0 electroproduction

Author: The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, G. Hill, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, N. Kobayashi, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, R. Lamb, L. Lapikás, I. Lehmann, P. Lenisa, L. A. Linden-Levy, A. López Ruiz, W. Lorenzon, X.-G. Lu, X.-R. Lu, B.-Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfré, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W.-D. Nowak, L. L. Pappalardo, R. Perez-Benito, N. Pickert, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schäfer, G. Schnell, K. P. Schüler, B. Seitz, T.-A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, F. Stinzing, S. Taroian, A. Terkulov, A. Trzcinski, M. Tytgat, A. Vandenbroucke, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, S. Yen, W. Yu, B. Zihlmann, and P. Zupranski
Subjects: Systematic Uncertainty, Amplitude Ratio, Total Uncertainty, Helicity Amplitude, ZEUS Collaboration, Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: Abstract Exclusive ρ 0-meson electroproduction is studied in the HERMES experiment, using a 27.6 GeV longitudinally polarized electron/positron beam and unpolarized hydrogen and deuterium targets in the kinematic region 0.5 GeV2
Published: 2011
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5. 'Professor2' Package for Tuning the Parameters of Fragmentation Process in e+e– Annihilation

Author: N. Z. Akopov, V. A. Muradyan, H. M. Ghumaryan, and G. A. Karyan
Subjects: Momentum, Particle physics, Annihilation, Pion, Generator (computer programming), Bar (music), Computer science, Process (computing), General Physics and Astronomy, High Energy Physics::Experiment, Nuclear Experiment, Free parameter, Market fragmentation
Abstract: The verification scheme in the package “Professor2” for setting parameters of the most used physics generator PYTHIA8.2 for simulating the processes in high energy physics is described. The goal is to tune the PYTHIA8.2 parameter list for the fragmentation process below $$b\bar {b}$$ the production threshold. As an initial parameter list, we use the Belle (predecessor of the Belle II experiment) default parameter settings for fragmentation. For the MC pseudo-data, we use the Belle II software package i.e. basf2, and generator script developed by the main author of this paper. To validate the whole procedure, we use momentum distribution of charged pions and kaons to tune two free parameters of the fragmentation model in PYTHIA8 i.e. LUND fragmentation model. We demonstrate that the Professor2 package is a handful to perform multi-parameter tunes simultaneously.
Published: 2021

6. Azimuthal single- and double-spin asymmetries in semi-inclusive deep-inelastic lepton scattering by transversely polarized protons

Author: P. E. Reimer, Vitaly Shutov, Wolfgang Lorenzon, G. Schnell, P. Lenisa, Ralf Kaiser, B. Seitz, V. Muccifora, P. Di Nezza, G. Nazaryan, T. A. Shibata, R.O. Avakian, P. Kravchenko, Dirk Ryckbosch, A. Rostomyan, Alessandro Bacchetta, B. Zihlmann, L. L. Pappalardo, L. Felawka, N. Akopov, G. Gavrilov, C. Riedl, W. Augustyniak, L. Lagamba, S. Yaschenko, G. Karyan, G. P. Capitani, Frank Ellinghaus, G. Ciullo, E. R. Kinney, Wouter Deconinck, H. E. Jackson, E. De Sanctis, B. Marianski, Y. Naryshkin, M. Contalbrigo, A. Airapetian, V. Gharibyan, Z. Akopov, G. Elbakian, P. Zupranski, Adel Terkulov, A. Ivanilov, R. De Leo, E. C. Aschenauer, A. Nass, S. I. Manaenkov, H. Marukyan, G. Rosner, S. Belostotski, A. Fantoni, A. Movsisyan, V. A. Kozlov, S. Joosten, D. Veretennikov, M. Diefenthaler, M. Statera, D. Zeiler, Y. Van Haarlem, A. Kisselev, Y. Holler, J. G. Rubin, Michael Tytgat, I. Lehmann, A. R. Reolon, V. Bryzgalov, E. Cisbani, C. B. Van Hulse, Y. Miyachi, D. Hasch, I. Vilardi, Michael Düren, W.-D. Nowak, L. Lapikás, Andreas Schäfer, and Klaus Rith
Subjects: dimension: 3, Nuclear Theory, HERMES, Parton, SIDIS, 01 natural sciences, PARTON, High Energy Physics - Experiment, Sivers function, High Energy Physics - Experiment (hep-ex), polarized beam [p], High Energy Physics - Phenomenology (hep-ph), semi-inclusive reaction [deep inelastic scattering], Polarization, leptoproduction [pi], Nuclear Experiment (nucl-ex), Collins, Nuclear Experiment, Spin-½, Quantum chromodynamics, Physics, FINAL-STATE INTERACTIONS, deep inelastic scattering: semi-inclusive reaction, PIONS, lepton: beam, ddc:530, QUARK POLARIZATION, scattering [lepton], anti-p, beam [lepton], High Energy Physics - Phenomenology, modulation, DESY HERA Stor, Fixed target experiments, kinematics, 3 [dimension], QCD, FRAGMENTATION, spin: asymmetry, electron p: deep inelastic scattering, Nuclear and High Energy Physics, DRELL-YAN, transverse [polarization], p: polarized beam, Socio-culturale, FOS: Physical sciences, lepton: scattering, SIVERS ASYMMETRIES, Nuclear physics, phase space, PE2_2, Pion, PE2_1, 0103 physical sciences, polarization: transverse, DISTRIBUTIONS, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, 010306 general physics, PE2_3, pi: leptoproduction, 010308 nuclear & particles physics, Scattering, ELECTROPRODUCTION, 530 Physik, Orientation (vector space), Antiproton, deep inelastic scattering [electron p], lcsh:QC770-798, High Energy Physics::Experiment, asymmetry [spin], experimental results, Lepton
Abstract: Journal of high energy physics 2020(12), 010 (2020). doi:10.1007/JHEP12(2020)010, A comprehensive set of azimuthal single-spin and double-spin asymmetries in semi-inclusive leptoproduction of pions, charged kaons, protons, and antiprotons from transversely polarized protons is presented. These asymmetries include the previously published HERMES results on Collins and Sivers asymmetries, the analysis of which has been extended to include protons and antiprotons and also to an extraction in a three-dimensional kinematic binning and enlarged phase space. They are complemented by corresponding results for the remaining four single-spin and four double-spin asymmetries allowed in the one-photon-exchange approximation of the semi-inclusive deep-inelastic scattering process for target-polarization orientation perpendicular to the direction of the incoming lepton beam. Among those results, significant non-vanishing $\cos(\phi−\phi_S)$ modulations provide evidence for a sizable worm-gear (II) distribution, $g_{1T}(x,p_T^2)$. Most of the other modulations are found to be consistent with zero with the notable exception of large $\sin(\phi_S)$ modulations for charged pions and $K^+$., Published by SISSA, [Trieste]
Published: 2020
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7. Beam-helicity asymmetries for single-hadron production in semi-inclusive deep-inelastic scattering from unpolarized hydrogen and deuterium targets

Author: G. Nazaryan, L. Lapikás, D. Veretennikov, Y. Holler, S. Yaschenko, Frank Ellinghaus, N. Akopov, E. R. Kinney, G. Schnell, G. Karyan, V. Bryzgalov, Ralf Kaiser, Wouter Deconinck, E. De Sanctis, V. Gharibyan, I. Vilardi, G. Gavrilov, H. E. Jackson, Vitaly Shutov, H. P. Blok, G. Elbakian, P. Zupranski, Wolfgang Lorenzon, A. Rostomyan, G. Rosner, S. Belostotski, A. Airapetian, S. I. Manaenkov, A. R. Reolon, B. Zihlmann, L. L. Pappalardo, B. Seitz, G. Ciullo, Michael Düren, H. Marukyan, F. Garibaldi, M. Diefenthaler, Dirk Ryckbosch, C. Riedl, T. A. Shibata, M. Contalbrigo, A. Nass, I. Lehmann, Y. Van Haarlem, A. Ivanilov, E. C. Aschenauer, C. Van Hulse, M. Statera, Michael Tytgat, A. Movsisyan, E. Cisbani, A. Hillenbrand, D. Zeiler, C. Vogel, P. Kravchenko, P. Di Nezza, G. Gapienko, V. Zagrebelnyy, A. Fantoni, Adel Terkulov, P. Lenisa, A. Trzcinski, V. Muccifora, W. Augustyniak, V. A. Kozlov, L. Felawka, L. Lagamba, G. P. Capitani, Z. Akopov, Klaus Rith, V. Korotkov, S. Joosten, A. Kisselev, B. Marianski, W.-D. Nowak, and Student Lab and Education
Subjects: HERMES experiment, odd fragmentation functions, Nuclear and High Energy Physics, parton distributions, Hadron, Nuclear Theory, Transverse-momentum dependence, Beam-helicity asymmetries, Nucleonstructure, Twist-3, Socio-culturale, FOS: Physical sciences, Electron, 01 natural sciences, 7. Clean energy, Nucleonstructure, High Energy Physics - Experiment, transverse-spin asymmetries, Nuclear physics, High Energy Physics - Experiment (hep-ex), PE2_2, Pion, PE2_1, factorization, 0103 physical sciences, twist-3, ddc:530, SDG 7 - Affordable and Clean Energy, drell-yan, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, PE2_3, Physics, deep-inelastic scattering, 010308 nuclear & particles physics, Scattering, polarimeter, Deep inelastic scattering, Helicity, lcsh:QC1-999, Deuterium, Physics and Astronomy, nucleon structure, Physics::Accelerator Physics, High Energy Physics::Experiment, transverse-momentum dependence, lcsh:Physics, beam-helicity asymmetries
Abstract: A measurement of beam-helicity asymmetries for single-hadron production in deep-inelastic scattering is presented. Data from the scattering of 27.6 GeV electrons and positrons off gaseous hydrogen and deuterium targets were collected by the HERMES experiment. The asymmetries are presented separately as a function of the Bjorken scaling variable, the hadron transverse momentum, and the fractional energy for charged pions and kaons as well as for protons and anti-protons. These asymmetries are also presented as a function of the three aforementioned kinematic variables simultaneously. (C) 2019 The Author. Published by Elsevier B.V. We gratefully acknowledge the DESY management for its support, the staff at DESY and the collaborating institutions for their significant effort. This work was supported by the State Committee of Science of the Republic of Armenia, Grant No. 18T-1C180; the FWO-Flanders and IWT, Belgium; the Natural Sciences and Engineering Research Council of Canada; the National Natural Science Foundation of China; the Alexander von Humboldt-Stiftung, the German Bundesministerium fur Bildung und Forschung (BMBF), and the Deutsche Forschungsgemeinschaft (DFG); the Italian Istituto Nazionale di Fisica Nucleare (INFN); the MEXT, JSPS, and G-COE of Japan; the Dutch Foundation for Fundamenteel Onderzoek der Materie (FOM); the Russian Academy of Sciences and the Russian Federal Agency for Science and Innovation; the Ikerbasque, Basque Foundation for Science, the Basque Government, Grant No. IT956-16, and MINECO (Juan de la Cierva), Spain; the U. K. Engineering and Physical Sciences Research Council, the Science and Technology Facilities Council, and the Scottish Universities Physics Alliance; as well as the U.S. Department of Energy (DOE) and the National Science Foundation (NSF).
Published: 2019
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8. Erratum to: Spin density matrix elements in exclusive $$\omega $$ electroproduction on $$^1$$H and $$^2$$H targets at 27.5 GeV beam energy

Author: P. E. Reimer, V. A. Kozlov, P. F. Dalpiaz, T. A. Shibata, B. Marianski, V. Bryzgalov, E. De Sanctis, V. Gharibyan, D. Hasch, G. Schnell, Morgan Murray, L. Felawka, F. Garibaldi, C. Riedl, W.-D. Nowak, G. Ciullo, L. Lagamba, G. P. Capitani, S. Joosten, A. Kisselev, C. Van Hulse, Wouter Deconinck, Luciano Pappalardo, Y. Van Haarlem, H. P. Blok, Z. Akopov, Michael Tytgat, E. Cisbani, Wolfgang Lorenzon, E. Etzelmüller, D. Zeiler, Frank Ellinghaus, Ivana Hristova, J. J. M. Steijger, Riccardo Fabbri, S. Yaschenko, Michael Düren, M. Ehrenfried, S. Taroian, B. Zihlmann, Y. J. Mao, P. Zupranski, M. Statera, A. R. Reolon, E. R. Kinney, Y. Naryshkin, V. A. Korotkov, Alexander Borissov, M. Capiluppi, B. Seitz, M. Diefenthaler, A. Movsisyan, H. Marukyan, A. Nass, I. Vilardi, R. Perez-Benito, G. Elbakian, B. Q. Ma, S. I. Manaenkov, Adel Terkulov, P. Di Nezza, R. Truty, M. Contalbrigo, R. De Leo, A. Airapetian, D. Gabbert, P. Kravchenko, Klaus Rith, A. Petrosyan, M. Hartig, S. Frullani, Dirk Ryckbosch, H. E. Jackson, V. G. Krivokhijine, S. Yen, A. Ivanilov, Ralf Kaiser, M. Stahl, L. Lapikás, E. Steffens, G. Gavrilov, David Mahon, Andreas Schäfer, I. Lehmann, V. A. Gapienko, T. Keri, V. Vikhrov, K. P. Schüler, Y. Holler, N. Akopov, G. Karyan, Shan Wang, A. Rostomyan, A. Avetissian, G. Gapienko, P. Lenisa, A. Trzcinski, W. Augustyniak, and M. Stancari
Subjects: Physics, Nuclear physics, Matrix (mathematics), Physics and Astronomy (miscellaneous), 010308 nuclear & particles physics, 0103 physical sciences, Atomic physics, Spin density, 010306 general physics, 01 natural sciences, Engineering (miscellaneous), Omega, Beam energy
Published: 2016

9. Transverse-target-spin asymmetry in exclusive $$\omega $$-meson electroproduction

Author: G. Ciullo, A. Movsisyan, A. Ivanilov, P. E. Reimer, Y. Holler, P. Lenisa, A. Trzcinski, F. Giordano, M. Contalbrigo, M. Negodaev, I. Lehmann, Klaus Rith, V. Muccifora, P. F. Dalpiaz, E. C. Aschenauer, G. Gapienko, G. Schnell, Frank Ellinghaus, V. A. Korotkov, B. Marianski, E. R. Kinney, Adel Terkulov, V. A. Gapienko, P. Zupranski, M. Statera, Y. Naryshkin, N. Akopov, E. De Sanctis, S. Yen, V. Gharibyan, W. Augustyniak, G. Karyan, G. Elbakian, Ralf Kaiser, S. I. Manaenkov, L. Lapikás, Michael Tytgat, Shan Wang, H. E. Jackson, Wouter Deconinck, V. G. Krivokhijine, S. Taroian, Y. Van Haarlem, S. Joosten, V. Vikhrov, E. Steffens, G. Rosner, R. Truty, A. Kisselev, C. Van Hulse, J. Rubin, M. Hoek, Y. Salomatin, B. Seitz, D. Gabbert, A. Rostomyan, C. Vogel, A. Avetissian, Y. J. Mao, B. Q. Ma, W.-D. Nowak, A. R. Reolon, A. Airapetian, A. Nass, B. Zihlmann, R. De Leo, L. L. Pappalardo, M. Diefenthaler, H. Marukyan, S. Belostotski, T. A. Shibata, V. Bryzgalov, Alexander Borissov, T. Keri, R. Perez-Benito, F. Stinzing, S. Frullani, P. Di Nezza, Dirk Ryckbosch, H. P. Blok, Wolfgang Lorenzon, S. Yaschenko, J. J. M. Steijger, Michael Düren, C. Riedl, Y. Miyachi, D. Hasch, I. Vilardi, A. Petrosyan, Z. Akopov, V. A. Kozlov, Stephen V. Gliske, L. Felawka, L. Lagamba, and G. P. Capitani
Subjects: Physics, Particle physics, Physics and Astronomy (miscellaneous), Meson, media_common.quotation_subject, Momentum transfer, DESY, Omega, Asymmetry, Nuclear physics, Pion, Positron, High Energy Physics::Experiment, Nuclear Experiment, Nucleon, Engineering (miscellaneous), media_common
Abstract: Hard exclusive electroproduction of omega mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive pi omega transition form factor.
Published: 2015

10. Transverse momentum broadening of hadrons produced in semi-inclusive deep-inelastic scattering on nuclei

Author: V. A. Korotkov, Wouter Deconinck, T. Keri, G. Elbakian, W.-D. Nowak, M. Hartig, S. Frullani, P. Di Nezza, D. Veretennikov, S. I. Manaenkov, Alessandra Fantoni, V. A. Gapienko, Cynthia Marie Hadjidakis, M. Hoek, Y. Miyachi, L. Manfré, A. Martinez de la Ossa, A. López Ruiz, P. E. Reimer, T. A. Shibata, G. Hill, A. Nass, F. Sanftl, V. Vikhrov, D. Hasch, M. Statera, Y. Van Haarlem, S. Belostotski, M. Capiluppi, V. Bryzgalov, D. Zeiler, C. Vogel, Xianguo Lu, M. Negodaev, W. Augustyniak, Ferdinando Giordano, M. Diefenthaler, H. Marukyan, H. S. Jo, B. Seitz, E. Nappi, Vitaly Shutov, H. P. Blok, A. Hillenbrand, Y. Imazu, J. Burns, David Mahon, Stephen V. Gliske, P. B. van der Nat, Morgan Murray, Wolfgang Lorenzon, Andreas Schäfer, L. Felawka, Frank Ellinghaus, Y. Salomatin, N. Akopov, E. R. Kinney, B. Marianski, E. De Sanctis, Ivana Hristova, L. Lagamba, Y. Naryshkin, J. J. M. Steijger, Michael Düren, M. Stancari, S. Yaschenko, C. Bonomo, E. Cisbani, H. E. Jackson, G. P. Capitani, R. Perez-Benito, B. Q. Ma, F. Garibaldi, P. F. Dalpiaz, R. Lamb, B. Ball, K. Rith, Z. Akopov, R. De Leo, Shan Wang, W. Yu, P. Lenisa, L. De Nardo, A. Trzcinski, Zhenyu Ye, J. Dreschler, I. Vilardi, H. Böttcher, V. Gharibyan, C. Riedl, Andreas Mussgiller, A. Rostomyan, A. R. Reolon, A. Avetissian, G. Ciullo, Arne Vandenbroucke, Riccardo Fabbri, E. Avetisyan, S. Joosten, A. Kisselev, V. Kozlov, A. Jgoun, J. G. Rubin, I. Lehmann, K. P. Schüler, Nicola Bianchi, P. Zupranski, L. A. Linden-Levy, J. Stewart, G. Rosner, A. Airapetian, F. Stinzing, G. Schnell, L. Lapikás, Valeria Muccifora, M. Contalbrigo, Hengqiang Ye, B. Zihlmann, L. L. Pappalardo, Martin Raithel, Alexander Borissov, Hasko Stenzel, Michael Tytgat, E. C. Aschenauer, S. Taroian, C. A. Miller, D. Gabbert, Ralf Kaiser, M. Ehrenfried, E. Steffens, N. C. R. Makins, N. Pickert, Dirk Ryckbosch, A. Movsisyan, Y. Holler, G. Karyan, Y. J. Mao, P. Kravchenko, X. R. Lu, C. B. Van Hulse, and A. Ivanilov
Subjects: HERMES experiment, Nuclear and High Energy Physics, Particle physics, Meson, DEUTERIUM, Hadron, FOS: Physical sciences, Virtual particle, 7. Clean energy, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), TARGETS, 0103 physical sciences, ddc:530, HADRONIZATION, Nuclear Experiment, 010306 general physics, Mass number, Physics, 010308 nuclear & particles physics, HERA, Deep inelastic scattering, Physics and Astronomy, High Energy Physics::Experiment, FRAGMENTATION, Lepton
Abstract: The first direct measurement of the dependence on target nuclear mass of the average squared transverse momentum of pi+, pi-, and K+ mesons from deep-inelastic lepton scattering is obtained as a function of several kinematic variables. The data were accumulated at the HERMES experiment at DESY, in which the HERA 27.6 GeV lepton beam was scattered off several nuclear gas targets. The average squared transverse momentum was clearly observed to increase with atomic mass number. The effect increases as a function of Q**2 and x and remains constant as a function of both the virtual photon energy nu and the fractional hadron energy z, except that it vanishes as z approaches unity., Comment: 6 pages, 2 figures
Published: 2010

11. Single-spin azimuthal asymmetry in exclusive electroproduction of π+ mesons on transversely polarized protons

Author: P. Lenisa, A. Trzcinski, S. Belostotski, Xianguo Lu, V. Bryzgalov, Wouter Deconinck, Adel Terkulov, J. J. M. Steijger, W. Augustyniak, I. Vilardi, Y. Holler, V. A. Korotkov, M. Varanda, R. Perez-Benito, M. Contalbrigo, David Mahon, Morgan Murray, J. Stewart, C. Riedl, Andreas Schäfer, Michael Tytgat, T. A. Shibata, B. Zihlmann, L. L. Pappalardo, C. B. Van Hulse, S. Taroian, D. Veretennikov, Hengqiang Ye, V. A. Gapienko, A. Ivanilov, C. Bonomo, E. Cisbani, Alexander Borissov, Hasko Stenzel, A. Airapetian, B. Seitz, E. C. Aschenauer, N. Akopov, F. Giordano, T. Keri, Vitaly Shutov, H. P. Blok, Naomi C R Makins, Y. J. Mao, P. Kravchenko, G. Elbakian, Y. Naryshkin, Wolfgang Lorenzon, M. Capiluppi, Valeria Muccifora, E. Avetisyan, S. I. Manaenkov, Dirk Ryckbosch, J. Burns, G. Ciullo, Ivana Hristova, S. Yaschenko, Frank Ellinghaus, Stephen V. Gliske, E. R. Kinney, V. Vikhrov, A. Hillenbrand, Y. Imazu, L. Felawka, P. B. van der Nat, A. Movsisyan, F. Sanftl, P. Zupranski, S. Yen, K. Rith, W.-D. Nowak, G. P. Capitani, Ralf Kaiser, M. Ehrenfried, M. Statera, J. Dreschler, D. Zeiler, L. Manfré, G. Rosner, R. Lamb, G. Hill, C. Vogel, E. De Sanctis, L. Lagamba, Eugenio Nappi, Z. Akopov, Nagao Kobayashi, F. Garibaldi, C. A. Miller, X. R. Lu, W. Yu, D. Gabbert, M. Diefenthaler, H. Marukyan, P. E. Reimer, Alessandra Fantoni, M. Hoek, H. S. Jo, A. Nass, H. E. Jackson, Shan Wang, Y. Salomatin, A. Rostomyan, A. R. Reolon, B. Q. Ma, A. Avetissian, B. Ball, R. De Leo, H. Böttcher, Andreas Mussgiller, A. López Ruiz, Y. Van Haarlem, B. Martinez de la Ossa, Michael Düren, M. Stancari, M. Hartig, S. Frullani, P. Di Nezza, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, K. P. Schüler, L. De Nardo, Zhenyu Ye, Nicola Bianchi, V. Gharibyan, J. G. Rubin, I. Lehmann, B. Marianski, P. F. Dalpiaz, Arne Vandenbroucke, Riccardo Fabbri, S. Joosten, A. Kisselev, L. A. Linden-Levy, G. Schnell, and L. Lapikás
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Photon, Proton, Meson, 010308 nuclear & particles physics, Scattering, media_common.quotation_subject, Virtual particle, 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, Photon polarization, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, media_common
Abstract: Exclusive electroproduction of π+ mesons was studied by scattering 27.6 GeV positrons or electrons off a transversely polarized hydrogen target. The single-spin azimuthal asymmetry with respect to target polarization was measured as a function of the Mandelstam variable t, the Bjorken scaling variable xB, and the virtuality Q2 of the exchanged photon. The extracted Fourier components of the asymmetry were found to be consistent with zero, except one that was found to be large and that involves interference of contributions from longitudinal and transverse virtual photons.
Published: 2010

12. Exclusive ρ0 electroproduction on transversely polarized protons

Author: P. Zupranski, C. A. Miller, P. Lenisa, A. Fantoni, T. A. Shibata, B. Zihlmann, L. L. Pappalardo, G. Rosner, D. Gabbert, Hengqiang Ye, A. Trzcinski, A. López Ruiz, Alexander Borissov, Hasko Stenzel, Xianguo Lu, T. Keri, G. Ciullo, W.-D. Nowak, S. Yen, M. Contalbrigo, M. Diefenthaler, E. C. Aschenauer, Ralf Kaiser, V. Muccifora, Naomi C R Makins, H. Marukyan, E. Steffens, Y. Van Haarlem, E. Avetisyan, Michael Tytgat, A. R. Reolon, A. Martinez de la Ossa, E. Cisbani, X. R. Lu, M. Ehrenfried, A. Hillenbrand, Y. Imazu, A. Airapetian, Stephen V. Gliske, F. Sanftl, S. Yaschenko, V. Vikhrov, M. Statera, C. Hadjidakis, L. Lagamba, S. Taroian, N. Akopov, Y. Salomatin, P. Di Nezza, B. Q. Ma, W. Augustyniak, D. Zeiler, M. Varanda, F. Stinzing, V. Bryzgalov, C. Vogel, Y. J. Mao, P. Kravchenko, B. Ball, Morgan Murray, L. Manfré, A. Movsisyan, M. Hartig, R. Lamb, R. De Leo, V. A. Korotkov, F. Giordano, David Mahon, J. Stewart, M. Hoek, C. B. Van Hulse, Adel Terkulov, L. Fellawka, Frank Ellinghaus, Andreas Schäfer, E. R. Kinney, R. Perez-Benito, A. Ivanilov, C. Bonomo, J. Burns, M. Capiluppi, H. Böttcher, H. E. Jackson, Y. Naryshkin, G. Elbakian, W. Yu, S. I. Manaenkov, A. Nass, J. G. Rubin, V. A. Gapienko, N. Bianchi, Andreas Mussgiller, Wouter Deconinck, G. Hill, Y. Holler, B. Seitz, I. Lehmann, K. Rith, E. Nappi, Z. Akopov, Nagao Kobayashi, P. B. van der Nat, J. Dreschler, P. E. Reimer, Shan Wang, D. Veretennikov, L. A. Linden-Levy, G. Schnell, C. Riedl, L. Lapikás, K. P. Schüler, Vitaly Shutov, P.F. Dalpiaz, A. Rostomyan, H. P. Blok, A. Avetissian, G.P. Capitani, H. S. Jo, Wolfgang Lorenzon, G. Gapienko, Ivana Hristova, E. De Sanctis, D. Hasch, S. Frullani, Dirk Ryckbosch, B. Marianski, Arne Vandenbroucke, Riccardo Fabbri, S. Joosten, A. Kisselev, J. J. M. Steijger, Michael Düren, M. Stancari, L. De Nardo, Zhenyu Ye, I. Vilardi, V. Gharibyan, Y. Miyachi, and (Astro)-Particles Physics
Subjects: 14.40.Aq, Quark, Nuclear and High Energy Physics, Particle physics, Meson, FOS: Physical sciences, HERMES, Parton, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Matrix (mathematics), 13.88.+e, GENERALIZED PARTON DISTRIBUTIONS, Total angular momentum quantum number, 0103 physical sciences, Proton spin crisis, ddc:530, NUCLEON, Nuclear Experiment, 010306 general physics, VIRTUAL COMPTON-SCATTERING, Physics, 010308 nuclear & particles physics, 13.60.Le, 14.20.Dh, 12.38.Qk, QCD, Helicity, TARGET, Physics and Astronomy, High Energy Physics::Experiment, SDG 6 - Clean Water and Sanitation, Nucleon, VECTOR-MESON PRODUCTION
Abstract: The exclusive electroproduction of rho-0 mesons was studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. Spin density matrix elements for this process were determined from the measured production- and decay-angle distributions of the produced rho-0 mesons. These matrix elements embody information on helicity transfer and the validity of s-channel helicity conservation in the case of a transversely polarized target. From the spin density matrix elements, the leading-twist term in the single-spin asymmetry was calculated separately for longitudinally and transversely polarized rho-0 mesons. Neglecting s-channel helicity changing matrix elements, results for the former can be compared to calculations based on generalized parton distributions, which are sensitive to the contribution of the total angular momentum of the quarks to the proton spin., 7 pages, 5 figures
Published: 2009

13. Measurement of parton distributions of strange quarks in the nucleon from charged-kaon production in deep-inelastic scattering on the deuteron

Author: A. Reischl, W. Augustyniak, R. Perez-Benito, B. Maiheu, Alessandra Fantoni, D. Veretennikov, M. Negodaev, B. Hommez, G. Ciullo, Tetsuya Hasegawa, M. Hoek, E. De Sanctis, V. A. Gapienko, W.H.A. Hesselink, B. Zihlmann, Y. Naryshkin, P. E. Reimer, A. Kisselev, J. G. Rubin, A. Brull, B. Tchuiko, M. Kopytin, Cynthia Marie Hadjidakis, Y. Miyachi, A. Nass, G. Gapienko, I. Lehmann, D. Hasch, A. López Ruiz, Z. Akopov, A. Elalaoui-Moulay, Frank Ellinghaus, C. Shearer, B. Seitz, A. Hillenbrand, Y. Imazu, E. Nappi, Y. Van Haarlem, Michael Tytgat, E. R. Kinney, Y. Holler, A. Airapetian, U. Elschenbroich, S. Taroian, P. Lenisa, David Mahon, Y. Salomatin, B. Marianski, A. Trzcinski, P. B. van der Nat, J. Burns, Shan Wang, F. Stinzing, Andreas Schäfer, H. E. Jackson, V. G. Krivokhijine, A. Funel, B. Q. Ma, J. J. M. Steijger, Michael Düren, G. van der Steenhoven, A. Osborne, M. Stancari, P. Zupranski, C. Riedl, S. E. Rock, P. Di Nezza, V. Vikhrov, L. Rubacek, R. De Leo, A. Rostomyan, K. Rith, C. B. Van Hulse, A. Borissov, A. R. Reolon, A. Avetissian, M. Capiluppi, P. Liebing, A. Ivanilov, S. Belostotski, G. Rosner, H. Böttcher, V. Bryzgalov, J. Dreschler, L. De Nardo, W. Yu, F. Garibaldi, Morgan Murray, G. Iarygin, Zhenyu Ye, E. C. Aschenauer, G. Hill, K. P. Schüler, Y. X. Ye, P.F. Dalpiaz, J. Stewart, I. Vilardi, Andreas Mussgiller, A. Andrus, M. Diefenthaler, V. Gharibyan, P. Tait, L. A. Linden-Levy, W.-D. Nowak, T. A. Shibata, E. Avetissian, M. Demey, Nicola Bianchi, R.O. Avakian, H. Marukyan, C. Bonomo, E. Cisbani, V. A. Kozlov, D. Reggiani, G. Schnell, F. Giordano, S. Joosten, J. Streit, I. M. Gregor, H. Ye, A. Jgoun, Arne Vandenbroucke, Riccardo Fabbri, L. Manfré, Stephen V. Gliske, H. Guler, M. Varanda, L. Felawka, X. R. Lu, L. Lagamba, S. Yen, G. P. Capitani, Ralf Kaiser, E. Steffens, G. Gavrilov, L. Lapikás, M. Contalbrigo, Martin Raithel, I. Sanjiev, Naomi C R Makins, M. Ehrenfried, Andrey V. Izotov, C. A. Miller, D. Gabbert, Tsutomu Kobayashi, M. Statera, S. Frullani, N. Pickert, Dirk Ryckbosch, D. Zeiler, C. Vogel, V. A. Korotkov, G. Elbakian, S. Lu, Y. J. Mao, P. Kravchenko, Adel Terkulov, T. Keri, L. L. Pappalardo, Hasko Stenzel, Wouter Deconinck, Valeria Muccifora, V. Mexner, A. Nagaitsev, N. Akopov, S. Yaschenko, Vitaly Shutov, H. P. Blok, Wolfgang Lorenzon, Ivana Hristova, R. Lamb, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education
Subjects: Quark, Particle physics, Strange quark, Nuclear and High Energy Physics, Nuclear Theory, FOS: Physical sciences, Parton, 01 natural sciences, NO, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 13.60.-r, 13.88.+e, 14.20.Dh, 14.65.-q, 0103 physical sciences, ddc:530, SDG 14 - Life Below Water, 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Scattering, Deep inelastic scattering, Helicity, Strange matter, Physics and Astronomy, High Energy Physics::Experiment, Nucleon
Abstract: The momentum and helicity density distributions of the strange quark sea in the nucleon are obtained in leading order from charged-kaon production in deep-inelastic scattering on the deuteron. The distributions are extracted from spin-averaged K+/- multiplicities, and from K+/- and inclusive double-spin asymmetries for scattering of polarized positrons by a polarized deuterium target. The shape of the momentum distribution is softer than that of the average of the ubar and dbar quarks. In the region of measurement 0.02 < x < 0.6 and Q^2 > 1.0 GeV^2, the helicity distribution is zero within experimental uncertainties., 5 pages, 5 figures, 1 table; text slightly expanded, 10 references added
Published: 2008
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14. Nuclear attenuation of high energy two-hadron system in the string model

Author: N. Akopov, L. Grigoryan, and Z. Akopov
Subjects: Physics, High energy, Particle physics, Physics and Astronomy (miscellaneous), Model prediction, Attenuation, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, FOS: Physical sciences, chemistry.chemical_element, Experimental data, Elementary particle, String (physics), Nuclear physics, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Xenon, chemistry, High Energy Physics::Experiment, Nuclear Experiment, Engineering (miscellaneous)
Abstract: Nuclear attenuation of the two-hadron system is considered in the string model. The two-scale model and its improved version with two different choices of constituent formation time and sets of parameters obtained earlier for the single hadron attenuation, are used to describe available experimental data for the $z$-dependence of subleading hadron, whereas satisfactory agreement with the experimental data has been observed. A model prediction for $\nu$-dependence of the nuclear attenuation of the two-hadron system is also presented., Comment: 8 pages
Published: 2007

15. Hadronization in semi-inclusive deep-inelastic scattering on nuclei

Author: P. Kravchenko, M. Stancari, R. Avakian, T. Hasegawa, E. Nappi, R. Perez-Benito, B. Marianski, C. Hadjidakis, Michael Tytgat, E. Cisbani, Frank Ellinghaus, Arne Vandenbroucke, H. Stenzel, Riccardo Fabbri, Y. Miyachi, E. R. Kinney, L. De Nardo, C. Shearer, B. Seitz, W.-D. Nowak, J.J.M. Steijger, E. C. Aschenauer, P. Lenisa, A. Kisselev, Stephen V. Gliske, X. R. Lu, G. Gapienko, G. Schnell, P. Zupranski, V. Gharibyan, A. Trzcinski, A. Brüll, P. B. van der Nat, H. Böttcher, A. Avetissian, G. Elbakian, P. Di Nezza, L. A. Linden-Levy, A. Rostomyan, J. Stewart, D. Gabbert, L. Rubacek, W. Yu, Klaus Rith, R. Lamb, I. Vilardi, H. E. Jackson, A.R. Reolon, C. Riedl, G. Rosner, Wouter Deconinck, A. Schäfer, Ralf Kaiser, M. Düren, Y. Naryshkin, Andreas Mussgiller, V. Muccifora, L. Lapikás, E. Avetissian, S. Taroian, P. E. Reimer, S. Yaschenko, V. Mexner, M. Hoek, S. Lu, W. Augustyniak, Morgan Murray, C. B. Van Hulse, Shan Wang, S. Frullani, B. Tchuiko, M. Kopytin, Z. Ye, S.E. Rock, Y. Ye, J. Dreschler, M. Varanda, A. Nass, B. Zihlmann, N. Pickert, G. Gavrilov, Y. Imazu, Z. Akopov, C. Bonomo, M. Statera, D. Veretennikov, T. Keri, F. Giordano, A. Airapetian, D. Zeiler, A. Ivanilov, N. Bianchi, C. Vogel, B. Hommez, B. Maiheu, T.-A. Shibata, V. Vikhrov, V. Gapienko, G. Ciullo, M. Demey, F. Stinzing, Y. Van Haarlem, J. Streit, H. P. Blok, L. L. Pappalardo, M. Contalbrigo, Wolfgang Lorenzon, I. Hristova, N. Akopov, Y. Salomatin, Martin Raithel, G. van der Steenhoven, L. Grigoryan, V. Korotkov, V. Shutov, L. Lagamba, Naomi C R Makins, V. Bryzgalov, M. Ehrenfried, R. De Leo, D. Hasch, F. Garibaldi, E. De Sanctis, M. Hartig, A. Fantoni, U. Elschenbroich, G. Hill, M. Negodaev, A. Reischl, G.P. Capitani, S. Yen, A. Hillenbrand, C.A. Miller, D. Reggiani, M. Diefenthaler, M. Capiluppi, P. Liebing, P.F. Dalpiaz, J. G. Rubin, I. Lehmann, D. Ryckbosch, H. Marukyan, A. Borissov, (Astro)-Particles Physics, and Student Lab and Education
Subjects: Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Hadron, chemistry.chemical_element, FOS: Physical sciences, 01 natural sciences, 7. Clean energy, NO, High Energy Physics - Experiment, Nuclear physics, Neon, High Energy Physics - Experiment (hep-ex), Pion, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, 010306 general physics, Nuclear Experiment, Physics, Mass number, 010308 nuclear & particles physics, Krypton, Deep inelastic scattering, Hadronization, chemistry, Deuterium, High Energy Physics::Experiment, Atomic physics
Abstract: A series of semi-inclusive deep-inelastic scattering measurements on deuterium, helium, neon, krypton, and xenon targets has been performed in order to study hadronization. The data were collected with the HERMES detector at the DESY laboratory using a 27.6 GeV positron or electron beam. Hadron multiplicities on nucleus A relative to those on the deuteron, R_A^h, are presented for various hadrons (\pi^+, \pi^-, \pi^0, K^+, K^-, p, and \bar{p}) as a function of the virtual-photon energy \nu, the fraction z of this energy transferred to the hadron, the photon virtuality Q^2, and the hadron transverse momentum squared p_t^2. The data reveal a systematic decrease of R_A^h with the mass number A for each hadron type h. Furthermore, R_A^h increases (decreases) with increasing values of \nu (z), increases slightly with increasing Q^2, and is almost independent of p_t^2, except at large values of p_t^2. For pions two-dimensional distributions also are presented. These indicate that the dependences of R_A^{\pi} on \nu and z can largely be described as a dependence on a single variable L_c, which is a combination of \nu and z. The dependence on L_c suggests in which kinematic conditions partonic and hadronic mechanisms may be dominant. The behaviour of R_A^{\pi} at large p_t^2 constitutes tentative evidence for a partonic energy-loss mechanism. The A-dependence of R_A^h is investigated as a function of \nu, z, and of L_c. It approximately follows an A^{\alpha} form with \alpha \approx 0.5 - 0.6., Comment: 33 pages, 12 figures
Published: 2007

16. Bose–Einstein correlations in hadron-pairs from lepto-production on nuclei ranging from hydrogen to xenon

Author: E. Nappi, Zhenyu Ye, I. Vilardi, V. A. Gapienko, N. Bianchi, G. Gapienko, F. Giordano, Adel Terkulov, V. Vikhrov, P. F. Dalpiaz, B. Marianski, J. Rubin, C. Van Hulse, Stephen V. Gliske, L. Felawka, V. A. Korotkov, L. Lagamba, P. E. Reimer, G. Elbakian, Morgan Murray, E. Avetisyan, G. P. Capitani, I. Lehmann, Frank Ellinghaus, Klaus Rith, P. Lenisa, G. Schnell, E. R. Kinney, S. Joosten, Y. Holler, M. Statera, Y. Miyachi, Y. Naryshkin, A. Trzcinski, A. Kisselev, A. Nass, D. Hasch, Shan Wang, Andreas Mussgiller, Luciano Pappalardo, B. Zihlmann, V. A. Kozlov, J. Garay Garcia, Alexander Borissov, W.-D. Nowak, M. Capiluppi, A. R. Reolon, Michael Tytgat, E. Cisbani, Z. Akopov, A. Martinez de la Ossa, A. López Ruiz, M. Diefenthaler, S. Taroian, Riccardo Fabbri, H. Marukyan, Y. Van Haarlem, A. Rostomyan, A. Avetissian, G. Ciullo, J. Burns, W. Augustyniak, N. C. R. Makins, Y. Salomatin, Xianguo Lu, M. Stancari, B. Q. Ma, S. Yen, Ralf Kaiser, H. E. Jackson, V. G. Krivokhijine, S. Frullani, M. Hartig, E. De Sanctis, V. Gharibyan, A. Movsisyan, S. Belostotski, J. J. M. Steijger, M. Negodaev, E. Etzelmüller, V. Bryzgalov, Dirk Ryckbosch, R. De Leo, Michael Düren, F. Garibaldi, G. Gavrilov, M. Stahl, A. Ivanilov, A. Fantoni, M. Contalbrigo, E. C. Aschenauer, David Mahon, D. Veretennikov, Andreas Schäfer, A. Petrosyan, Y. J. Mao, T. Keri, Wouter Deconinck, L. Lapikás, N. Akopov, G. Karyan, P. Di Nezza, P. Kravchenko, S. Yaschenko, R. Perez-Benito, Vitaly Shutov, H. P. Blok, Wolfgang Lorenzon, Ivana Hristova, C. Riedl, Y. Imazu, A. Airapetian, T. A. Shibata, R.O. Avakian, P. Zupranski, G. Rosner, R. Truty, and B. Seitz
Subjects: Physics, Nuclear reaction, HERMES experiment, Physics and Astronomy (miscellaneous), Hadron, Elementary particle, Bose–Einstein correlations, Deep inelastic scattering, Charged particle, Nuclear physics, Pair production, Atomic physics, Nuclear Experiment, Engineering (miscellaneous)
Abstract: Bose–Einstein correlations of like-sign charged hadrons produced in deep-inelastic electron and positron scattering are studied in the HERMES experiment using nuclear targets of $$^1$$ H, $$^2$$ H, $$^3$$ He, $$^4$$ He, N, Ne, Kr, and Xe. A Gaussian approach is used to parametrize a two-particle correlation function determined from events with at least two charged hadrons of the same sign charge. This correlation function is compared to two different empirical distributions that do not include the Bose–Einstein correlations. One distribution is derived from unlike-sign hadron pairs, and the second is derived from mixing like-sign pairs from different events. The extraction procedure used simulations incorporating the experimental setup in order to correct the results for spectrometer acceptance effects, and was tested using the distribution of unlike-sign hadron pairs. Clear signals of Bose–Einstein correlations for all target nuclei without a significant variation with the nuclear target mass are found. Also, no evidence for a dependence on the invariant mass W of the photon-nucleon system is found when the results are compared to those of previous experiments.
Published: 2015

17. PentaquarkΘ+search at HERMES

Author: A. Petrosyan, C. A. Miller, W. Augustyniak, R. Perez-Benito, D. Gabbert, B. Zihlmann, Alexander Borissov, Xianguo Lu, M. Negodaev, H. E. Jackson, V. G. Krivokhijine, T. Keri, V. Vikhrov, Shan Wang, I. Vilardi, S. Yaschenko, Y. Salomatin, G. Schnell, E. De Sanctis, Morgan Murray, G. Elbakian, Y. Holler, P. Zupranski, S. I. Manaenkov, Franco Garibaldi, J. Garay Garcia, A. Trzcinski, J. J. M. Steijger, P. Kravchenko, W.-D. Nowak, L. Lagamba, Z. Akopov, Michael Tytgat, A. Rostomyan, A. R. Reolon, A. Avetissian, Hengqiang Ye, B. Q. Ma, E. Cisbani, S. Taroian, G. Rosner, R. Truty, P. E. Reimer, C. Van Hulse, Y. Imazu, D. Hasch, R. De Leo, Salvatore Frullani, Riccardo Fabbri, K. P. Schüler, A. Martinez de la Ossa, B. Seitz, F. Giordano, P. F. Dalpiaz, M. Stancari, E. Avetisyan, J. Bowles, G. Ciullo, Adel Terkulov, Zhenyu Ye, H. P. Blok, Eugenio Nappi, T. A. Shibata, Dirk Ryckbosch, R.O. Avakian, A. Movsisyan, Alessandra Fantoni, Wolfgang Lorenzon, A. López Ruiz, A. Ivanilov, M. Hartig, P. Di Nezza, Y. Van Haarlem, S. Yen, A. Nass, Ivana Hristova, Stephen V. Gliske, J. G. Rubin, I. Lehmann, Ralf Kaiser, David Mahon, L. Felawka, B. Marianski, Y. Miyachi, G. P. Capitani, G. Gavrilov, S. Joosten, A. Kisselev, V. Kozlov, Luciano Pappalardo, M. Contalbrigo, C. Riedl, E. Etzelmüller, Klaus Rith, E. R. Kinney, S. Belostotski, V. Bryzgalov, J. Burns, H. Marukyan, N. Akopov, D. Veretennikov, L. Lapikás, G. Karyan, Wouter Deconinck, and Y. J. Mao
Subjects: RING, Nuclear and High Energy Physics, Particle physics, Baryon production, 01 natural sciences, Particle identification, NO, DECUPLET, Nuclear physics, 0103 physical sciences, Baryons, Invariant mass, Nuclear Experiment, 010306 general physics, Glueball and nonstandard multi-quark, SKYRME MODEL, BARYONS, Physics, 010308 nuclear & particles physics, Hyperon, Pentaquark, Baryon, Physics and Astronomy, Deuterium, Excited state, High Energy Physics::Experiment, Event (particle physics), Glueball and nonstandard multi-quark, Pentaquark, Baryon production, Baryons
Abstract: The earlier search at HERMES for narrow baryon states excited in quasireal photoproduction, decaying through the channel pK(S)(0) -> p pi(+)pi(-), has been extended with improved decay-particle reconstruction, more advanced particle identification, and increased event samples. The structure observed earlier at an invariant mass of 1528 MeV shifts to 1522 MeV and the statistical significance drops to about 2 sigma for data taken with a deuterium target. The number of events above background is 68(-31)(+98)(stat) +/- 13(sys). No such structure is observed in the hydrogen data set.
Published: 2015

18. Hard exclusive electroproduction of π+π−π+π− pairs

Author: A. Airapetian, N. Akopov, Z. Akopov, M. Amarian, V.V. Ammosov, A. Andrus, E.C. Aschenauer, W. Augustyniak, R. Avakian, and A. Avetissian
Subjects: Nuclear and High Energy Physics
Published: 2004

19. Spin density matrix elements in exclusive $$\omega $$ ω electroproduction on $$^1$$ 1 H and $$^2$$ 2 H targets at 27.5 GeV beam energy

Author: P. Lenisa, A. Trzcinski, L. Lapikás, B. Seitz, S. Frullani, W. Augustyniak, M. Stancari, B. Q. Ma, Frank Ellinghaus, Riccardo Fabbri, V. A. Kozlov, Dirk Ryckbosch, E. R. Kinney, G. Schnell, A. Petrosyan, E. De Sanctis, V. Gharibyan, A. Ivanilov, C. Van Hulse, A. Airapetian, Y. Naryshkin, P. Di Nezza, N. Akopov, I. Lehmann, R. De Leo, H. E. Jackson, M. Diefenthaler, Shan Wang, V. G. Krivokhijine, P. F. Dalpiaz, T. A. Shibata, R. Perez-Benito, D. Zeiler, H. Marukyan, E. Etzelmüller, C. Riedl, G. Karyan, B. Marianski, Y. J. Mao, P. Kravchenko, V. A. Korotkov, W.-D. Nowak, V. A. Gapienko, P. E. Reimer, A. Rostomyan, Klaus Rith, A. Avetissian, S. Joosten, G. Ciullo, A. Kisselev, A. Nass, I. Vilardi, Michael Tytgat, E. Cisbani, G. Gapienko, G. Elbakian, K. P. Schüler, S. Taroian, T. Keri, Luciano Pappalardo, S. I. Manaenkov, Morgan Murray, L. Felawka, Wouter Deconinck, L. Lagamba, H. P. Blok, A. Movsisyan, David Mahon, G. P. Capitani, Wolfgang Lorenzon, V. Vikhrov, V. Bryzgalov, Y. Holler, Andreas Schäfer, Ivana Hristova, J. J. M. Steijger, S. Yaschenko, Michael Düren, F. Garibaldi, Z. Akopov, D. Hasch, M. Contalbrigo, M. Hartig, P. Zupranski, Y. Van Haarlem, R. Truty, S. Yen, Ralf Kaiser, E. Steffens, G. Gavrilov, A. R. Reolon, M. Stahl, Adel Terkulov, D. Gabbert, M. Ehrenfried, M. Statera, B. Zihlmann, Alexander Borissov, and M. Capiluppi
Subjects: Physics, Density matrix, HERMES experiment, Particle physics, Physics and Astronomy (miscellaneous), Meson, 010308 nuclear & particles physics, Hadron, Elementary particle, 01 natural sciences, Helicity, Omega, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Spin-flip, Nuclear Experiment, 010306 general physics, Engineering (miscellaneous)
Abstract: Spin Density Matrix Elements (SDMEs) describing the angular distribution of exclusive ρ 0 electroproduction and decay are determined in the HERMES experiment with 27.6 GeV beam energy and unpolarized hydrogen and deuterium targets. Eight (fifteen) SDMEs that are related (unrelated) to the longitudinal polarization of the beam are extracted in the kinematic region 1
Published: 2014

20. Reevaluation of the parton distribution of strange quarks in the nucleon

Author: S. Belostotski, V. Bryzgalov, M. Diefenthaler, Paolo Lenisa, S. Joosten, A. Kisselev, V. Kozlov, Luciano Pappalardo, S. Frullani, D. Hasch, Dirk Ryckbosch, P. Zupranski, C. Riedl, Y. Miyachi, W. Augustyniak, B. Marianski, Frank Ellinghaus, T. Keri, M. Ehrenfried, E. R. Kinney, Adel Terkulov, Xianguo Lu, W.-D. Nowak, M. Hoek, G. Gapienko, V. Vikhrov, Morgan Murray, M. Negodaev, G. Rosner, R. Truty, A. Trzcinski, M. Hartig, Y. Naryshkin, I. Vilardi, D. Gabbert, A. Ivanilov, H. P. Blok, E. Avetisyan, P. Di Nezza, Zhenyu Ye, H. E. Jackson, Wolfgang Lorenzon, A. Nass, M. Stahl, V. Gharibyan, V. G. Krivokhijine, B. Zihlmann, Ivana Hristova, S. Yaschenko, Alexander Borissov, B. Seitz, Y. Holler, J. G. Rubin, M. Capiluppi, C. Van Hulse, J. J. M. Steijger, I. Lehmann, Michael Düren, David Mahon, Valeria Muccifora, M. Statera, E. De Sanctis, Franco Garibaldi, Andreas Schäfer, P. E. Reimer, A. Movsisyan, E. Etzelmüller, L. Lapikás, C. Vogel, Shan Wang, Y. Van Haarlem, J. Burns, V. A. Korotkov, A. Rostomyan, A. R. Reolon, A. Avetissian, K. Rith, A. Petrosyan, G. Elbakian, S. I. Manaenkov, A. Airapetian, D. Veretennikov, Y. Salomatin, F. Stinzing, Stephen V. Gliske, L. Felawka, B. Q. Ma, G. P. Capitani, H. Marukyan, L. Lagamba, Z. Akopov, R. De Leo, Andreas Mussgiller, G. Ciullo, V. A. Gapienko, R. Perez-Benito, G. Schnell, J. Garay Garcia, S. Yen, Ralf Kaiser, Wouter Deconinck, E. Steffens, G. Gavrilov, M. Contalbrigo, F. Giordano, E. C. Aschenauer, P. F. Dalpiaz, T. A. Shibata, N. Akopov, G. Karyan, Y. J. Mao, P. Kravchenko, Michael Tytgat, E. Cisbani, and S. Taroian
Subjects: HERMES experiment, Quark, Nuclear and High Energy Physics, Strange quark, Particle physics, Distribution (number theory), strangeness [nucleon], Nuclear Theory, FOS: Physical sciences, Parton, HERMES, 01 natural sciences, sea [strangeness], High Energy Physics - Experiment, x-dependence, Nuclear physics, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), semi-inclusive reaction [deep inelastic scattering], 0103 physical sciences, ddc:530, 010306 general physics, Nuclear Experiment, HIGH-ENERGY COLLISIONS, Physics, 010308 nuclear & particles physics, Scattering, High Energy Physics - Phenomenology, DESY HERA Stor, Physics and Astronomy, High Energy Physics::Experiment, multiplicity [K], deep inelastic scattering [electron deuteron], Nucleon, distribution function [parton]
Abstract: An earlier extraction from the HERMES experiment of the polarization-averaged parton distribution of strange quarks in the nucleon has been reevaluated using final data on the multiplicities of charged kaons in semi-inclusive deep-inelastic scattering obtained with a kinematically more comprehensive method of correcting for experimental effects. General features of the distribution are confirmed, but the rise at low $x$ is less pronounced than previously reported.
Published: 2014

21. Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons

Author: J. Burns, G. Gapienko, J. J. M. Steijger, Michael Düren, Riccardo Fabbri, K. Rith, H. E. Jackson, Michael Tytgat, E. Cisbani, M. Stancari, M. Golembiovskaya, D. Veretennikov, T. Keri, V. G. Krivokhijine, E. Avetisyan, M. Capiluppi, A. Petrosyan, G. Ciullo, S. Taroian, A. Hillenbrand, M. Negodaev, L. De Nardo, Zhenyu Ye, P. E. Reimer, M. Contalbrigo, Shan Wang, S. Yaschenko, I. Vilardi, C. Hadjidakis, Martin Raithel, P. Di Nezza, Frank Ellinghaus, E. C. Aschenauer, W.-D. Nowak, B. Seitz, E. Nappi, J. Bowles, V. Vikhrov, P. Lenisa, E. R. Kinney, B. Marianski, V. A. Korotkov, V. A. Gapienko, C. A. Miller, E. De Sanctis, V. Gharibyan, A. Martinez de la Ossa, Y. Naryshkin, Morgan Murray, N. Bianchi, A. Rostomyan, V. Zagrebelnyy, A. Fantoni, A. Avetissian, D. Gabbert, L. Lapikás, David Mahon, P. F. Dalpiaz, Andreas Schäfer, A. Trzcinski, Stephen V. Gliske, S. Joosten, Wouter Deconinck, M. Ehrenfried, A. Kisselev, L. Felawka, F. Giordano, N. C. R. Makins, G. Elbakian, L. Lagamba, A. R. Reolon, Y. Miyachi, S. Belostotski, V. Bryzgalov, S. I. Manaenkov, Vitaly Shutov, H. P. Blok, S. Frullani, D. Hasch, G. P. Capitani, A. Airapetian, Wolfgang Lorenzon, Dirk Ryckbosch, W. Yu, P. Kravchenko, C. Van Hulse, R. Perez-Benito, Andreas Mussgiller, Ivana Hristova, M. Statera, J. Stewart, W. Augustyniak, D. Zeiler, S. Yen, T. A. Shibata, V. A. Kozlov, R.O. Avakian, F. Stinzing, Ralf Kaiser, G. Schnell, E. Steffens, G. Gavrilov, M. Hartig, P. Zupranski, Z. Akopov, C. Riedl, M. Hoek, N. Akopov, J. G. Rubin, I. Lehmann, G. Rosner, R. Truty, G. Karyan, Y. J. Mao, Adel Terkulov, A. López Ruiz, Y. Van Haarlem, Y. Salomatin, B. Q. Ma, R. De Leo, B. Zihlmann, L. L. Pappalardo, Alexander Borissov, F. Sanftl, M. Diefenthaler, H. Marukyan, A. Movsisyan, A. Ivanilov, Y. Holler, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HERMES, Student Lab and Education, and (Astro)-Particles Physics
Subjects: HERMES experiment, Hadron, Nuclear Theory, analizing power, Electron, 01 natural sciences, sivers asymmetries, High Energy Physics - Experiment, CROSS-SECTIONS, DEEP-INELASTIC SCATTERING, High Energy Physics - Experiment (hep-ex), hard scattering, arrow-p, Mathematics::Probability, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], chiral-odd contibution, Nuclear Experiment (nucl-ex), cross-sections, Nuclear Experiment, ARROW-P, media_common, Physics, polarized proton-beam, POLARIZED PROTON-BEAM, CHIRAL-ODD CONTRIBUTION, SIVERS ASYMMETRIES, ANALYZING POWER, 200 GEV/C, PI(0) PRODUCTION, HARD SCATTERING, deep-inelastic scattering, ddc:530, PI(0) production, PHYSICS, NUCLEAR, Transverse plane, symbols, Particle physics, Nuclear and High Energy Physics, media_common.quotation_subject, Mathematics::Analysis of PDEs, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Asymmetry, Mathematics::Numerical Analysis, Nuclear physics, symbols.namesake, Pion, 0103 physical sciences, Feynman diagram, SDG 7 - Affordable and Clean Energy, 010306 general physics, 010308 nuclear & particles physics, Deep inelastic scattering, 530 Physik, Physics and Astronomy, High Energy Physics::Experiment
Abstract: Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle $\psi$ about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum relative to the direction of the incident beam, and the Feynman variable $x_F$. The $\sin(\psi)$ amplitudes are positive for positive pions and kaons, slightly negative for negative pions and consistent with zero for negative kaons, with particular transverse-momentum but weak $x_F$ dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer., Comment: 10 pages, 5 figures
Published: 2014

22. Azimuthal distributions of charged hadrons, pions, and kaons produced in deep-inelastic scattering off unpolarized protons and deuterons

Author: A. Trzcinski, J. Burns, N. C. R. Makins, S. Frullani, A. Hillenbrand, Y. Imazu, K. Rith, Dirk Ryckbosch, Adel Terkulov, V. A. Gapienko, A. Ivanilov, Y. Holler, S. Yen, G. Gapienko, J. Bowles, J. G. Rubin, David Mahon, M. Golembiovskaya, Ralf Kaiser, F. Sanftl, I. Lehmann, Michael Tytgat, E. Cisbani, Andreas Schäfer, A. Movsisyan, C. A. Miller, W. Yu, F. Giordano, Wouter Deconinck, V. Zagrebelnyy, B. Marianski, B. Zihlmann, G. Ciullo, W. Augustyniak, G. Gavrilov, Alexander Borissov, H. E. Jackson, C. Van Hulse, V. G. Krivokhijine, H. P. Blok, T. A. Shibata, M. Statera, R.O. Avakian, A. Airapetian, M. Capiluppi, Arne Vandenbroucke, M. Stancari, Alessandra Fantoni, Y. Naryshkin, W.-D. Nowak, Shan Wang, Wolfgang Lorenzon, D. Zeiler, E. De Sanctis, Franco Garibaldi, P. F. Dalpiaz, L. Manfré, P. E. Reimer, M. Hoek, Ivana Hristova, A. Martinez de la Ossa, A. López Ruiz, D. Veretennikov, Paolo Lenisa, S. Yaschenko, S. Joosten, M. Negodaev, I. Vilardi, V. A. Korotkov, Eugenio Nappi, A. Kisselev, V. Kozlov, Luciano Pappalardo, Y. Van Haarlem, A. Rostomyan, A. R. Reolon, A. Avetissian, Y. J. Mao, P. Kravchenko, L. Lapikás, T. Keri, M. Diefenthaler, A. Nass, H. S. Jo, F. Stinzing, J. Stewart, G. Schnell, M. Contalbrigo, E. Avetisyan, G. Elbakian, S. I. Manaenkov, Martin Raithel, E. C. Aschenauer, R. Perez-Benito, V. Vikhrov, M. Hartig, A. Petrosyan, P. Di Nezza, C. Riedl, Morgan Murray, B. Seitz, D. Hasch, K. P. Schüler, P. Zupranski, G. Rosner, R. Truty, N. Akopov, S. Belostotski, G. Karyan, V. Bryzgalov, Frank Ellinghaus, E. R. Kinney, Y. Salomatin, B. Q. Ma, H. Marukyan, R. De Leo, Stephen V. Gliske, L. Felawka, L. Lagamba, Z. Akopov, L. De Nardo, Zhenyu Ye, V. Gharibyan, J. J. M. Steijger, Michael Düren, Cynthia Marie Hadjidakis, and Y. Miyachi
Subjects: Drell-Yan process, HERMES experiment, generalized parton distribution, Nuclear Theory, Hadron, HERMES, Parton, 01 natural sciences, multiple production [charged particle], High Energy Physics - Experiment, HARD-SCATTERING, High Energy Physics - Experiment (hep-ex), semi-inclusive reaction [deep inelastic scattering], transverse momentum [parton], HERMES EXPERIMENT, deep inelastic scattering [positron p], Collins, Nuclear Experiment (nucl-ex), Nuclear Experiment, electroproduction [pi], Physics, FINAL-STATE INTERACTIONS, ANGULAR-DISTRIBUTIONS, PARTON-MODEL, DUAL RADIATOR RICH, angular dependence, modulation, DESY HERA Stor, SPIN PRODUCTION ASYMMETRIES, Nucleon, Quark, Nuclear and High Energy Physics, Particle physics, DRELL-YAN, FOS: Physical sciences, Nuclear physics, angular distribution [charged particle], Pion, 0103 physical sciences, ddc:530, PHYSICS EVENT GENERATION, TRANSVERSE-MOMENTUM, 010306 general physics, deep inelastic scattering [lepton deuteron], 27.6 GeV, 010308 nuclear & particles physics, Scattering, High Energy Physics::Phenomenology, polarization [quark], Deep inelastic scattering, Physics and Astronomy, electroproduction [K], deep inelastic scattering [electron p], High Energy Physics::Experiment, experimental results
Abstract: The azimuthal cos{\phi} and cos2{\phi} modulations of the distribution of hadrons produced in unpolarized semi-inclusive deep-inelastic scattering of electrons and positrons off hydrogen and deuterium targets have been measured in the HERMES experiment. For the first time these modulations were determined in a four-dimensional kinematic space for positively and negatively charged pions and kaons separately, as well as for unidentified hadrons. These azimuthal dependences are sensitive to the transverse motion and polarization of the quarks within the nucleon via, e.g., the Cahn, Boer-Mulders and Collins effects.
Published: 2013

23. Multiplicities of charged pions and kaons from semi-inclusive deep-inelastic scattering by the proton and the deuteron

Author: N. Akopov, G. Karyan, V. A. Korotkov, Y. J. Mao, A. Trzcinski, Wouter Deconinck, Frank Ellinghaus, E. R. Kinney, A. Petrosyan, W.-D. Nowak, Andreas Mussgiller, David Mahon, J. Burns, Vitaly Shutov, H. P. Blok, G. Elbakian, L. Manfré, A. Martinez de la Ossa, P. E. Reimer, Wolfgang Lorenzon, Andreas Schäfer, C. A. Miller, Ivana Hristova, Eugenio Nappi, L. De Nardo, Alessandra Fantoni, S. Yaschenko, S. I. Manaenkov, A. Hillenbrand, Y. Imazu, L. Lagamba, M. Diefenthaler, I. Vilardi, S. Belostotski, M. Hoek, Shan Wang, B. Zihlmann, P. F. Dalpiaz, Z. Akopov, Nagao Kobayashi, Zhenyu Ye, V. Zagrebelnyy, V. Bryzgalov, F. Garibaldi, H. S. Jo, W. Augustyniak, Riccardo Fabbri, C. Van Hulse, Alexander Borissov, A. López Ruiz, D. Gabbert, M. Statera, K. Rith, V. Gharibyan, Y. Naryshkin, M. Stancari, Y. Van Haarlem, M. Capiluppi, J. Bowles, I. Brodski, D. Zeiler, C. Vogel, Y. Salomatin, A. Nass, M. Golembiovskaya, A. Rostomyan, A. R. Reolon, A. Avetissian, H. E. Jackson, Stephen V. Gliske, T. Keri, M. Contalbrigo, D. Veretennikov, V. G. Krivokhijine, B. Q. Ma, Martin Raithel, G. Gapienko, J. J. M. Steijger, E. C. Aschenauer, H. Marukyan, R. De Leo, L. Felawka, B. Marianski, Michael Düren, E. De Sanctis, C. Riedl, W. Yu, G. P. Capitani, Michael Tytgat, Adel Terkulov, M. Ehrenfried, Cynthia Marie Hadjidakis, Y. Miyachi, Paolo Lenisa, E. Cisbani, S. Joosten, T. A. Shibata, A. Kisselev, V. Kozlov, V. Gapienko, R.O. Avakian, Morgan Murray, S. Taroian, S. Yen, Luciano Pappalardo, B. Seitz, Andrey V. Izotov, Ralf Kaiser, E. Avetisyan, N. C. R. Makins, E. Steffens, G. Gavrilov, S. Frullani, Dirk Ryckbosch, R. Perez-Benito, B. Maiheu, F. Giordano, G. Ciullo, J. G. Rubin, I. Lehmann, M. Hartig, P. Di Nezza, D. Hasch, M. Negodaev, A. Airapetian, F. Stinzing, G. Schnell, A. Ivanilov, L. Lapikás, P. Kravchenko, J. Stewart, Y. Holler, P. Zupranski, G. Rosner, R. Truty, F. Sanftl, and A. Movsisyan
Subjects: HERMES experiment, AZIMUTHAL DEPENDENCE, FRAGMENTATION FUNCTIONS, Hadron, Parton, HERMES, momentum transfer dependence, 01 natural sciences, 7. Clean energy, CROSS-SECTIONS, High Energy Physics - Experiment, 13.60.-r, 13.60.Le, 13.87.Fh, 14.20.Dh, High Energy Physics - Experiment (hep-ex), semi-inclusive reaction [deep inelastic scattering], LEPTOPRODUCTION, MONTE-CARLO, deep inelastic scattering [positron p], Nuclear Experiment (nucl-ex), Nuclear Experiment, electroproduction [pi], Physics, HERA, fragmentation [quark], DESY HERA Stor, CHAMBERS, FACTORIZATION, Quark, Nuclear and High Energy Physics, Particle physics, Meson, PARTON MODEL, FOS: Physical sciences, x-dependence, Nuclear physics, Pion, 0103 physical sciences, ddc:530, 010306 general physics, deep inelastic scattering [lepton deuteron], 010308 nuclear & particles physics, 27.6 GeV, High Energy Physics::Phenomenology, ELECTROPRODUCTION, Deep inelastic scattering, multiplicity: measured [charged particle], Physics and Astronomy, electroproduction [K], deep inelastic scattering [electron p], High Energy Physics::Experiment, experimental results
Abstract: Multiplicities in semi-inclusive deep-inelastic scattering are presented for each charge state of ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ and ${\mathrm{K}}^{\ifmmode\pm\else\textpm\fi{}}$ mesons. The data were collected by the HERMES experiment at the HERA storage ring using 27.6 GeV electron and positron beams incident on a hydrogen or deuterium gas target. The results are presented as a function of the kinematic quantities ${x}_{\mathrm{B}}$, ${Q}^{2}$, $z$, and ${P}_{h\ensuremath{\perp}}$. They represent a unique data set for identified hadrons that will significantly enhance our understanding of the fragmentation of quarks into final-state hadrons in deep-inelastic scattering.
Published: 2012

24. Measurements of double-spin asymmetries associated with deeply virtual Compton scattering on a transversely polarized hydrogen target

Author: V. A. Korotkov, David Mahon, V. A. Kozlov, Andreas Schäfer, Y. J. Mao, G. Ciullo, W. Augustyniak, G. Elbakian, V. Zagrebelnyy, E. De Sanctis, Paolo Lenisa, S. Joosten, V. Gharibyan, G. Gapienko, A. Kisselev, S. I. Manaenkov, P. E. Reimer, Klaus Rith, A. R. Reolon, J. Burns, Y. Naryshkin, P. Kravchenko, M. Hoek, N. C. R. Makins, Z. Akopov, X. R. Lu, M. Contalbrigo, A. Movsisyan, S. Belostotski, V. Bryzgalov, A. Trzcinski, V. A. Gapienko, Martin Raithel, E. C. Aschenauer, N. Bianchi, F. Garibaldi, S. Frullani, B. Marianski, A. Nass, Y. Holler, Adel Terkulov, I. Brodski, E. Avetisyan, Dirk Ryckbosch, S. Yen, Y. Imazu, Ralf Kaiser, P. F. Dalpiaz, H. S. Jo, M. Golembiovskaya, N. Akopov, B. Seitz, E. Nappi, C. A. Miller, Morgan Murray, G. Karyan, A. Fantoni, E. Steffens, Stephen V. Gliske, D. Gabbert, G. Gavrilov, C. Riedl, J. Bowles, Shan Wang, L. Felawka, Wouter Deconinck, L. Lagamba, Riccardo Fabbri, D. Veretennikov, Michael Tytgat, E. Cisbani, G. P. Capitani, M. Statera, D. Zeiler, S. Taroian, P. Di Nezza, F. Giordano, M. Capiluppi, C. B. Van Hulse, B. Zihlmann, Xianguo Lu, M. Negodaev, L. L. Pappalardo, T. A. Shibata, R. Perez-Benito, A. Ivanilov, H. E. Jackson, Alexander Borissov, V. G. Krivokhijine, R.O. Avakian, Vitaly Shutov, H. P. Blok, A. Rostomyan, A. Avetissian, T. Keri, Frank Ellinghaus, Wolfgang Lorenzon, E. R. Kinney, Ivana Hristova, S. Yaschenko, V. Vikhrov, L. Manfré, K. P. Schüler, P. Zupranski, J. G. Rubin, I. Lehmann, G. Rosner, R. Truty, M. Hartig, A. Airapetian, F. Stinzing, A. López Ruiz, Y. Van Haarlem, Andreas Mussgiller, Y. Salomatin, B. Q. Ma, M. Ehrenfried, H. Marukyan, R. De Leo, Y. Miyachi, D. Hasch, G. Schnell, L. Lapikás, J. J. M. Steijger, Michael Düren, W.-D. Nowak, M. Stancari, A. Martinez de la Ossa, L. De Nardo, Zhenyu Ye, and I. Vilardi
Subjects: Nuclear and High Energy Physics, Photon, EVOLUTION KERNELS, HERA, FOS: Physical sciences, HERMES, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), GPDs, GENERALIZED PARTON DISTRIBUTIONS, 0103 physical sciences, ddc:530, NUCLEON, 010306 general physics, DVCS, GPDs, HERMES experiments, Transversely polarized hydrogen target, Physics, Quantum chromodynamics, 010308 nuclear & particles physics, Compton scattering, Transversely polarized hydrogen target, HERMES experiments, Polarization (waves), QCD, Helicity, Transverse plane, Physics and Astronomy, ELECTRON STORAGE-RING, DVCS, Nucleon
Abstract: Double-spin asymmetries in exclusive electroproduction of real photons from a transversely polarized hydrogen target are measured with respect to the product of target polarization with beam helicity and beam charge, and with respect to the product of target polarization with beam helicity alone. The asymmetries arise from the deeply virtual Compton scattering process and its interference with the Bethe--Heitler process. They are related to the real part of the same combination of Compton form factors as that determining the previously published transverse target single-spin asymmetries through the imaginary part. The results for the double-spin asymmetries are found to be compatible with zero within the uncertainties of the measurement, and are not incompatible with the predictions of the only available GPD-based calculation., Comment: 9 pages, 4 figures, and 3 tables
Published: 2011

25. NUMERICAL DETERMINATION OF FRACTAL AND ENTROPY CHARACTERISTICS OF THE SEISMIC PROCESS ON THE TERRITORY OF ARMENIA

Author: A. Yu. Shahverdian and N. Z. Akopov
Subjects: Fractal, Applied Mathematics, Modeling and Simulation, Numerical analysis, Entropy (information theory), Geometry and Topology, Statistical physics, Geology, Physics::Geophysics
Abstract: An application of certain methods of the theory of dynamical chaos to researching of the seismic process is considered. By means of computer-assisted processing of the earthquakes catalogue the numerical values of the fractal, information and correlation dimensions for this process on the territory of Armenia are determined. Using the numerical method, the inequality K>0 for the Kolmogorov-Sinay entropy K for seismic process is examined.
Published: 1993

26. Effects of transversity in deep-inelastic scattering by polarized protons

Author: N. C. R. Makins, B. Seitz, U. Elschenbroich, Stephen V. Gliske, G. Gapienko, L. Felawka, G. P. Capitani, P. B. van der Nat, S. Frullani, R. Lamb, F. Sanftl, G. Hill, N. Pickert, Dirk Ryckbosch, Y. J. Mao, P. Kravchenko, J. G. Rubin, A. Movsisyan, C. A. Miller, I. Lehmann, L. Lapikás, Xianguo Lu, M. Negodaev, D. Veretennikov, M. Statera, Y. Holler, Alessandra Fantoni, M. Hoek, S. Belostotski, D. Gabbert, A. Trzcinski, V. A. Gapienko, D. Zeiler, E. De Sanctis, J. Stewart, Y. Salomatin, C. Vogel, V. Bryzgalov, F. Garibaldi, Shan Wang, P. E. Reimer, W. Yu, Paolo Lenisa, L. A. Linden-Levy, S. Joosten, F. Giordano, A. Nass, P. Zupranski, A. Kisselev, J. Burns, Wouter Deconinck, S. Yen, V. A. Korotkov, G. Schnell, Frank Ellinghaus, E. R. Kinney, Hengqiang Ye, P. F. Dalpiaz, Adel Terkulov, T. A. Shibata, C. B. Van Hulse, B. Q. Ma, V. Kozlov, M. Ehrenfried, Luciano Pappalardo, K. Rith, A. Rostomyan, A. R. Reolon, E. Avetisyan, Ralf Kaiser, A. Avetissian, A. Ivanilov, R.O. Avakian, H. S. Jo, H. Marukyan, R. De Leo, G. Ciullo, M. Golembiovskaya, E. Steffens, N. Akopov, G. Elbakian, M. Hartig, G. Karyan, G. Rosner, S. I. Manaenkov, P. Di Nezza, Riccardo Fabbri, W. Augustyniak, M. Diefenthaler, A. López Ruiz, B. Zihlmann, M. Contalbrigo, Michael Tytgat, E. Cisbani, M. Stancari, Alessandro Bacchetta, H. E. Jackson, Martin Raithel, Alexander Borissov, Hasko Stenzel, M. Capiluppi, Y. Van Haarlem, S. Taroian, Nicola Bianchi, T. Keri, R. Perez-Benito, A. Hillenbrand, Y. Imazu, B. Marianski, X. R. Lu, J. Bowles, A. Airapetian, Andreas Mussgiller, F. Stinzing, V. Vikhrov, I. Vilardi, S. Yaschenko, L. De Nardo, Zhenyu Ye, E. C. Aschenauer, Morgan Murray, V. Gharibyan, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, J. J. M. Steijger, Michael Düren, L. Lagamba, Z. Akopov, Nagao Kobayashi, David Mahon, Andreas Schäfer, Y. Naryshkin, C. Riedl, Vitaly Shutov, H. P. Blok, Wolfgang Lorenzon, W.-D. Nowak, L. Manfré, A. Martinez de la Ossa, Ivana Hristova, Eugenio Nappi, and I. Brodsky
Subjects: Nuclear and High Energy Physics, Antiparticle, Meson, Hadron, FOS: Physical sciences, HERMES, Inelastic scattering, COLLINS, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, ASYMMETRIES, LEPTOPRODUCTION, 0103 physical sciences, DISTRIBUTIONS, ddc:530, QUARKS, 010306 general physics, NUCLEON, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Scattering, Collins function, Deep inelastic scattering, QCD, Polarized structure functions, TARGET, Physics and Astronomy, Single-spin asymmetries, Transversity, Antimatter, Semi-inclusive DIS, High Energy Physics::Experiment, Atomic physics
Abstract: Single-spin asymmetries for pions and charged kaons are measured in semi-inclusive deep-inelastic scattering of positrons and electrons off a transversely nuclear-polarized hydrogen target. The dependence of the cross section on the azimuthal angles of the target polarization (phi_S)and the produced hadron (phi) is found to have a substantial sin(phi+phi_S) modulation for the production of pi+, pi- and K+. This Fourier component can be interpreted in terms of non-zero transversity distribution functions and non-zero favored and disfavored Collins fragmentation functions with opposite sign. For pi0 and K- production the amplitude of this Fourier component is consistent with zero., Comment: 7 pages, 3 figures
Published: 2010

27. Search for a Two-Photon Exchange Contribution to Inclusive Deep-Inelastic Scattering

Author: J. Burns, V. A. Korotkov, M. Hartig, P. Di Nezza, C. Riedl, B. Marianski, G. Gapienko, Morgan Murray, K. Rith, W. Augustyniak, K. P. Schüler, W. Yu, G. Elbakian, Michael Tytgat, E. Cisbani, S. Yaschenko, C. Bonomo, P.F. Dalpiaz, Nicola Bianchi, J. J. M. Steijger, Michael Düren, M. Stancari, J. G. Rubin, I. Lehmann, C. B. Van Hulse, A. Ivanilov, D. Veretennikov, S. Taroian, Arne Vandenbroucke, P. E. Reimer, B. Zihlmann, L. L. Pappalardo, Wouter Deconinck, Riccardo Fabbri, E. De Sanctis, T. A. Shibata, R.O. Avakian, Ferdinando Giordano, I. Vilardi, F. Sanftl, Alexander Borissov, Hasko Stenzel, Vitaly Shutov, H. P. Blok, Shan Wang, F. Garibaldi, L. De Nardo, Zhenyu Ye, L. Lagamba, Z. Akopov, David Mahon, A. Trzcinski, Wolfgang Lorenzon, Y. Holler, T. Keri, M. Statera, Paolo Lenisa, A. Hillenbrand, Y. Imazu, Ivana Hristova, D. Zeiler, M. Varanda, S. Joosten, V. Gharibyan, Y. J. Mao, P. Kravchenko, Andreas Schäfer, A. Kisselev, C. A. Miller, V. Kozlov, X. R. Lu, J. Bowles, V. Vikhrov, A. Rostomyan, A. R. Reolon, Stephen V. Gliske, A. Avetissian, Ralf Kaiser, Frank Ellinghaus, E. Avetisyan, M. Diefenthaler, L. Felawka, Cynthia Marie Hadjidakis, E. Steffens, H. S. Jo, E. R. Kinney, G. P. Capitani, G. Ciullo, Y. Miyachi, M. Contalbrigo, Martin Raithel, D. Hasch, E. C. Aschenauer, M. Ehrenfried, Y. Naryshkin, R. Lamb, Adel Terkulov, A. Movsisyan, N. C. R. Makins, N. Akopov, S. Frullani, Dirk Ryckbosch, G. Karyan, S. Belostotski, V. Bryzgalov, H. E. Jackson, Valeria Muccifora, G. Schnell, L. Lapikás, R. Perez-Benito, G. Hill, Xianguo Lu, M. Negodaev, D. Gabbert, J. Stewart, V. A. Gapienko, Hengqiang Ye, W.-D. Nowak, L. Manfré, A. Martinez de la Ossa, H. Böttcher, Andreas Mussgiller, Y. Salomatin, B. Q. Ma, B. Ball, H. Marukyan, A. López Ruiz, Y. Van Haarlem, A. Airapetian, B. Seitz, P. B. van der Nat, F. Stinzing, P. Zupranski, Alessandra Fantoni, M. Hoek, G. Rosner, and A. Nass
Subjects: Quark, Nuclear and High Energy Physics, Particle physics, ELECTRON-PROTON, VIOLATION, media_common.quotation_subject, DEUTERIUM, FOS: Physical sciences, Electron, 13.60.-r, 13.60.Hb, 13.88.+e, 14.20.Dh, 14.65.-q, 01 natural sciences, Asymmetry, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Positron, NUCLEON SCATTERING, 0103 physical sciences, ddc:530, EXCHANGE, 010306 general physics, Nuclear Experiment, POSITRON SCATTERING, media_common, Physics, 010308 nuclear & particles physics, Scattering, HYDROGEN, Polarization (waves), Deep inelastic scattering, INVARIANCE, TARGET, Physics and Astronomy, Deuterium, Physics::Accelerator Physics, High Energy Physics::Experiment
Abstract: The transverse-target single-spin asymmetry for inclusive deep-inelastic scattering with effectively unpolarized electron and positron beams off a transversely polarized hydrogen target was measured, with the goal of searching for a two-photon exchange signal in the kinematic range 0.007 < x_B < 0.9 and 0.25 GeV**2 < Q**2 < 20 GeV**2. In two separate regions Q**2 > 1 GeV**2 and Q**2 < 1 GeV**2, and for both electron and positron beams, the asymmetries are found to be consistent with zero within statistical and systematic uncertainties, which are of order 10**(-3) for the asymmetries integrated over x_B., 5 pages, 1 figure, revised text
Published: 2009
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28. Observation of the Naive-T-odd Sivers Effect in Deep-Inelastic Scattering

Author: P. Lenisa, A. Trzcinski, P. E. Reimer, C. A. Miller, E. De Sanctis, V. Gharibyan, Franco Garibaldi, A. López Ruiz, E. Avetisyan, V. A. Korotkov, Alessandra Fantoni, M. Hoek, M. Contalbrigo, Y. Van Haarlem, L. Lagamba, Z. Akopov, G. Elbakian, D. Gabbert, Y. Salomatin, K. P. Schüler, S. I. Manaenkov, B. Q. Ma, B. Ball, C. B. Van Hulse, Frank Ellinghaus, A. Nass, E. R. Kinney, R. De Leo, H. S. Jo, B. Zihlmann, Shan Wang, Nicola Bianchi, Y. Naryshkin, R. Perez-Benito, E. Cisbani, Alexander Borissov, A. Ivanilov, W. Yu, Xianguo Lu, M. Negodaev, H. Böttcher, J. G. Rubin, M. Ehrenfried, F. Sanftl, Hasko Stenzel, S. Yen, M. Capiluppi, I. Lehmann, W. Augustyniak, J. Stewart, M. Statera, Ralf Kaiser, Andreas Mussgiller, V. A. Gapienko, A. Hillenbrand, Y. Imazu, C. Riedl, S. Yaschenko, Hengqiang Ye, M. Stancari, P. Zupranski, G. Ciullo, D. Zeiler, A. Rostomyan, A. R. Reolon, A. Avetissian, V. Bryzgalov, C. Vogel, H. E. Jackson, A. Movsisyan, N. C. R. Makins, B. Seitz, G. Gapienko, Y. Holler, Stephen V. Gliske, T. A. Shibata, Wouter Deconinck, U. Elschenbroich, Adel Terkulov, Michael Tytgat, J. J. M. Steijger, Michael Düren, P. B. van der Nat, Dirk Ryckbosch, G. Rosner, Vitaly Shutov, H. P. Blok, X. R. Lu, L. Felawka, Wolfgang Lorenzon, S. Taroian, Ivana Hristova, G. Hill, G. P. Capitani, D. Veretennikov, Salvatore Frullani, M. Hartig, P. F. Dalpiaz, R. Lamb, P. Di Nezza, F. Giordano, J. Burns, N. Akopov, K. Rith, A. Airapetian, Y. J. Mao, P. Kravchenko, M. Diefenthaler, J. Dreschler, L. De Nardo, Zhenyu Ye, E. C. Aschenauer, F. Stinzing, David Mahon, Andreas Schäfer, H. Marukyan, L. A. Linden-Levy, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, G. Schnell, W.-D. Nowak, L. Manfré, A. Martinez de la Ossa, L. Lapikás, Eugenio Nappi, C. Bonomo, M. Varanda, T. Keri, V. Vikhrov, Morgan Murray, I. Vilardi, B. Marianski, Arne Vandenbroucke, Riccardo Fabbri, Alessandro Bacchetta, S. Joosten, A. Kisselev, V. Kozlov, Luciano Pappalardo, (Astro)-Particles Physics, Network Institute, Student Lab and Education, and Artificial Intelligence (section level)
Subjects: Particle physics, Meson, Polarized hydrogen target, Hadron, General Physics and Astronomy, FOS: Physical sciences, Elementary particle, Parton, Inelastic scattering, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Transverse momentum dependents, High Energy Physics - Experiment (hep-ex), Pion, 0103 physical sciences, ddc:550, 010306 general physics, Nuclear Experiment, Physics, Cross section, 010308 nuclear & particles physics, Scattering, Deep inelastic scattering, Parton distribution functions, Single-spin asymmetries, Hydrogen, Distribution functions, High Energy Physics::Experiment
Abstract: Azimuthal single-spin asymmetries of lepto-produced pions and charged kaons were measured on a transversely polarized hydrogen target. Evidence for a naive-T-odd, transverse-momentum-dependent parton distribution function is deduced from non-vanishing Sivers effects for pi+, pi0, and K+, K-, as well as in the difference of the pi+ and pi- cross sections., Comment: 6 pages, 4 figures
Published: 2009

29. Nuclear-mass dependence of azimuthal beam-helicity and beam-charge asymmetries in deeply virtual Compton scattering

Author: Y. Holler, D. Veretennikov, Xianguo Lu, M. Negodaev, F. Giordano, Y. Salomatin, P. E. Reimer, M. Contalbrigo, Alessandra Fantoni, Hengqiang Ye, M. Hoek, Rezo Shanidze, Martin Raithel, E. C. Aschenauer, J. Burns, B. Zihlmann, Michael Tytgat, A. Nass, B. Q. Ma, M. Hartig, P. Lenisa, K. Rith, V. A. Korotkov, S. Taroian, Alexander Borissov, B. Ball, C. B. Van Hulse, M. Capiluppi, H. S. Jo, M. Ehrenfried, T. Keri, Salvatore Frullani, M. Statera, A. Airapetian, R. De Leo, A. Ivanilov, P. F. Dalpiaz, Stephen V. Gliske, Shan Wang, V. A. Gapienko, E. Avetisyan, P. Di Nezza, A. Trzcinski, M. Diefenthaler, Valeria Muccifora, C. A. Miller, C. Riedl, G. Elbakian, S. I. Manaenkov, H. Marukyan, N. Akopov, L. Felawka, M. Amarian, S. Yaschenko, S. Haan, G. Hill, S. Joosten, V. Vikhrov, J. G. Rubin, F. Stinzing, X. R. Lu, A. López Ruiz, G. Karyan, I. Lehmann, N. C. R. Makins, G. P. Capitani, W. Yu, A. Kisselev, W. Augustyniak, V. Kozlov, Wouter Deconinck, Ralf Kaiser, Y. Van Haarlem, S. Belostotski, R. Lamb, V. Bryzgalov, Dirk Ryckbosch, M. Stancari, L. Lagamba, Adel Terkulov, A. Rostomyan, A. R. Reolon, G. Ciullo, A. Avetissian, E. Steffens, Luciano Pappalardo, Z. Akopov, T. A. Shibata, P. Zupranski, I. Vilardi, G. Gavrilov, H. Böttcher, R.O. Avakian, G. Gapienko, D. Zeiler, R. Perez-Benito, H. E. Jackson, E. Cisbani, Vadim Guzey, B. Marianski, D. Gabbert, Morgan Murray, K. P. Schüler, Andreas Mussgiller, E. De Sanctis, J. Stewart, Frank Ellinghaus, G. Rosner, Franco Garibaldi, Vitaly Shutov, H. P. Blok, A. Movsisyan, E. R. Kinney, Nicola Bianchi, Wolfgang Lorenzon, Y. Naryshkin, Arne Vandenbroucke, Riccardo Fabbri, A. Hillenbrand, Y. Imazu, Ivana Hristova, J. Bowles, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, L. De Nardo, Zhenyu Ye, V. Gharibyan, J. J. M. Steijger, Michael Düren, W.-D. Nowak, L. Manfré, A. Martinez de la Ossa, H. Guler, Eugenio Nappi, G. Schnell, L. Lapikás, M. Varanda, David Mahon, Andreas Schäfer, Y. J. Mao, and P. Kravchenko
Subjects: Nuclear and High Energy Physics, Particle physics, Photon, Nuclear Theory, HERA, FOS: Physical sciences, IMPACT PARAMETER SPACE, Parton, GENERALIZED PARTON DISTRIBUTIONS, SPIN, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, ddc:530, Nuclear Experiment, 010306 general physics, Physics, Elastic scattering, 010308 nuclear & particles physics, Scattering, Compton scattering, Physics::Accelerator Physics, High Energy Physics::Experiment, Nucleon, Beam (structure)
Abstract: The nuclear-mass dependence of azimuthal cross section asymmetries with respect to charge and longitudinal polarization of the lepton beam is studiedfor hard exclusive electroproduction of real photons. The observed beam-charge and beam-helicity asymmetries are attributed to the interference between the Bethe-Heitler and deeply virtual Compton scattering processes. For various nuclei, the asymmetries are extracted for both coherent and incoherent-enriched regions, which involve different (combinations of) generalized parton distributions. For both regions, the asymmetries are compared to those for a free proton, and no nuclear-mass dependence is found., Comment: 11 pages, 9 figures, 4 tables, minor revisions of text
Published: 2009

30. Backward production of mesons associated with? ++(1232) in? + p interactions at 20 GeV/c

Author: Ara Grigoryan, Antonio Ferrer, A. S. Zhokin, V. I. Mikhailichenko, V. V. Karapetyan, L. Dorsaz, N. Z. Akopov, V.F. Perepelitsa, S. Ya. Nikitin, and P. Sonderegger
Subjects: Density matrix, Physics, Baryon, Nuclear physics, Crystallography, Meson production, Physics and Astronomy (miscellaneous), Proton, Meson, Pi, Elementary particle, Engineering (miscellaneous), Omega
Abstract: We have analyzed backward meson production inπ + p reactions at 20GeV/c, which were measured in the CERN Ω spectrometer triggered by a fast proton (p f ), in experiment WA56. Production via baryon exchange of quasi-two-body final statesΔ ++ (1232)ρ 0 (770),Δ ++ (1232)f 2 (1270), andΔ ++ (1232)ρ 3 0 (1690) is clearly identified. The density matrix elements of meson resonances and ofΔ ++ (1232) are analyzed. We have observed also the reactionsπ + p→Δ ++ (1232)π 0 andπ + p→Δ ++ (1232)ω in thep f π + π 0 andp f π + π + π − π 0 final states.
Published: 1991

31. Measurement of Azimuthal Asymmetries With Respect To Both Beam Charge and Transverse Target Polarization in Exclusive Electroproduction of Real Photons

Author: HERMES collaboration, A Airapetian, N Akopov, Z Akopov, A Andrus, E.C Aschenauer, W Augustyniak, R Avakian, A Avetissian, E Avetisyan, L Barion, S Belostotski, N Bianchi, H.P Blok, H Böttcher, C Bonomo, A Borissov, A Brüll, V Bryzgalov, J Burns, M Capiluppi, G.P Capitani, E Cisbani, G Ciullo, M Contalbrigo, P.F Dalpiaz, W Deconinck, R. De Leo, M Demey, L. De Nardo, E. De Sanctis, M Diefenthaler, P. Di Nezza, J Dreschler, M Düren, M Ehrenfried, G Elbakian, F Ellinghaus, U Elschenbroich, R Fabbri, A Fantoni, L Felawka, S Frullani, A Funel, D Gabbert, G Gapienko, V Gapienko, F Garibaldi, G Gavrilov, V Gharibyan, F Giordano, S Gliske, H Guler, C Hadjidakis, D Hasch, T Hasegawa, G Hill, A Hillenbrand, M Hoek, Y Holler, I Hristova, G Iarygin, Y Imazu, A Ivanilov, A Izotov, H.E Jackson, A Jgoun, S Joosten, R Kaiser, T Keri, E Kinney, A Kisselev, M Kopytin, V Korotkov, V Kozlov, P Kravchenko, V.G Krivokhijine, L Lagamba, R Lamb, L Lapikás, I Lehmann, P Lenisa, L.A Linden-Levy, W Lorenzon, S Lu, X Lu, B.-Q Ma, D Mahon, B Maiheu, N.C.R Makins, Y Mao, B Marianski, H Marukyan, C.A Miller, Y Miyachi, V Muccifora, M Murray, A Mussgiller, A Nagaitsev, E Nappi, Y Naryshkin, A Nass, M Negodaev, W.-D Nowak, A Osborne, L.L Pappalardo, R Perez-Benito, N Pickert, M Raithel, P.E Reimer, A Reischl, A.R Reolon, C Riedl, K Rith, S.E Rock, G Rosner, A Rostomyan, L Rubacek, J Rubin, A.L Ruiz, D Ryckbosch, Y Salomatin, I Sanjiev, A Schäfer, G Schnell, K.P Schüler, B Seitz, C Shearer, T.-A Shibata, V Shutov, M Stancari, M Statera, E Steffens, J.J.M Steijger, H Stenzel, J Stewart, F Stinzing, P Tait, S Taroian, A Terkulov, A Trzcinski, M Tytgat, A Vandenbroucke, P.B. van der Nat, G. van der Steenhoven, Y. Van Haarlem, C. Van Hulse, M Varanda, D Veretennikov, V Vikhrov, I Vilardi, C Vogel, S Wang, S Yaschenko, H Ye, Z Ye, S Yen, W Yu, D Zeiler, B Zihlmann, P Zupranski, (Astro)-Particles Physics, and Student Lab and Education
Subjects: Quark, Physics, Nuclear and High Energy Physics, Particle physics, Photon, 010308 nuclear & particles physics, media_common.quotation_subject, Lepton-Nucleon Scattering, Compton scattering, FOS: Physical sciences, Parton, Polarization (waves), 01 natural sciences, Asymmetry, NO, High Energy Physics - Experiment, Transverse plane, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, ddc:530, High Energy Physics::Experiment, 010306 general physics, Nucleon, Nuclear Experiment, media_common
Abstract: Azimuthal asymmetries in exclusive electroproduction of real photons are measured for the first time with respect to transverse target polarisation, providing new constraints on Generalized Parton Distributions. From the same data set on a hydrogen target, new results for the beam-charge asymmetry are also extracted with better precision than those previously reported. By comparing model calculations with measured asymmetries attributed to the interference between the deeply virtual Compton scattering and Bethe-Heitler processes, a model-dependent constraint is obtained on the total angular momenta carried by up and down quarks in the nucleon., 24 pages, 10 figures, 2 tables; 1 figure,3 references added, slight text change
Published: 2008

32. Cross sections for hard exclusive electroproduction of pi(+) mesons on a hydrogen target

Author: W. Augustyniak, A. López Ruiz, Vitaly Shutov, H. P. Blok, Y. Van Haarlem, M. Hoek, M. Kopytin, A. Nass, V. A. Gapienko, N. Bianchi, Wolfgang Lorenzon, Ivana Hristova, C. B. Van Hulse, A. Ivanilov, P. E. Reimer, S. Yaschenko, H. Böttcher, E. De Sanctis, V. Gharibyan, C. Shearer, B. Seitz, E. Nappi, P. B. van der Nat, P. Lenisa, Z. Akopov, Arne Vandenbroucke, P. Zupranski, G. Gapienko, Andreas Mussgiller, A. Trzcinski, Riccardo Fabbri, T. A. Shibata, A. Kisselev, J. G. Rubin, I. Lehmann, E. Avetissian, H. Ye, S. Lu, S. Frullani, V. Muccifora, G. Rosner, G. Hill, Morgan Murray, N. Pickert, M. Statera, W.-D. Nowak, L. A. Linden-Levy, H. Guler, G. Ciullo, S. E. Rock, Y. Salomatin, Dirk Ryckbosch, M. Negodaev, A. Airapetian, W. Yu, G. Schnell, D. Zeiler, S. Joosten, J. Streit, A. Hillenbrand, Y. Imazu, C. Vogel, A. Borissov, H. E. Jackson, L. L. Pappalardo, K. P. Schüler, P.F. Dalpiaz, Stephen V. Gliske, L. Barion, S. Yen, V. G. Krivokhijine, Hasko Stenzel, E. Thomas, F. Stinzing, C. Bonomo, V. A. Korotkov, Shan Wang, L. Lapikás, F. Giordano, T. Keri, L. Lagamba, Ralf Kaiser, M. Ehrenfried, M. Varanda, P. Di Nezza, R. De Leo, R. Perez-Benito, B. Marianski, R. Lamb, H. Marukyan, D. Hasch, J. J. M. Steijger, C. Riedl, G. Elbakian, Michael Düren, M. Stancari, V. Vikhrov, L. Rubacek, M. Diefenthaler, G. Gavrilov, S. Belostotski, V. Bryzgalov, C. A. Miller, M. Capiluppi, A. Rostomyan, A. Avetissian, F. Garibaldi, A. Fantoni, D. Gabbert, J. Stewart, A. R. Reolon, L. De Nardo, Zhenyu Ye, Frank Ellinghaus, Michael Tytgat, E. Cisbani, E. R. Kinney, I. Vilardi, S. Taroian, X. R. Lu, Y. Naryshkin, M. Contalbrigo, Martin Raithel, E. C. Aschenauer, B. Zihlmann, Y. Miyachi, Naomi C R Makins, P. Kravchenko, Alexander Ilyichev, Wouter Deconinck, N. Akopov, D. Veretennikov, M. Demey, G.P. Capitani, Klaus Rith, J. Burns, C. Hadjidakis, J. Dreschler, G. van der Steenhoven, David Mahon, Andreas Schäfer, (Astro)-Particles Physics, and Student Lab and Education
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Scattering, Four-momentum, Virtual particle, FOS: Physical sciences, DESY, Parton, Electron, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Positron, 0103 physical sciences, ddc:530, High Energy Physics::Experiment, 010306 general physics, Nuclear Experiment, SDG 6 - Clean Water and Sanitation
Abstract: The exclusive electroproduction of pi+ mesons was studied with the Hermes spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off an internal hydrogen gas target. The virtual-photon cross sections were measured as a function of the Mandelstam variable t and the squared four momentum -Q^2 of the exchanged virtual photon. A model calculation based on Generalized Parton Distributions is in fair agreement with the data at low values of |t| if power corrections are included. A model calculation based on the Regge formalism gives a good description of the magnitude and the t and Q^2 dependences of the cross section., Comment: 7 pages, 5 figures, revised text
Published: 2008

33. Transverse polarization ofΛandΛ¯hyperons in quasireal photoproduction

Author: I. Brunn, A. Kisselev, J. Wilbert, W. Augustyniak, Alessandra Fantoni, G. Graw, B. D. Fox, B. Zihlmann, M. Stancari, V. Mexner, B. Tchuiko, M. Kopytin, A. Nass, G. Schnell, O. Grebeniouk, A. Nagaitsev, B. Hommez, P. E. Reimer, P. Lenisa, J. Seibert, A. Trzcinski, Michel Vetterli, M. Henoch, E. Thomas, A. Laziev, M. Vogt, D. Reggiani, N. Akopov, B. Seitz, S. Tessarin, P. B. van der Nat, Katerina Lipka, K. Oganessyan, G. Iarygin, F. Masoli, J. Visser, A. Jgoun, V. A. Gapienko, G. M. Urciuoli, H. Kolster, Dirk Ryckbosch, M. Amarian, V. Vikhrov, Adel Terkulov, R. Van de Vyver, S. Belostotski, Manuella Vincter, H. Marukyan, Hidekazu Tanaka, M. Statera, Rezo Shanidze, J. Franz, Salvatore Frullani, Y. Gärber, J. Stewart, L. G. Greeniaus, V. A. Korotkov, A. Brüll, F. Menden, P. F. Dalpiaz, V. V. Ammosov, S. Yen, H. E. Jackson, A. Tkabladze, V. G. Krivokhijine, Andrey V. Izotov, C. Weiskopf, Ralf Kaiser, H. P. Blok, H. C. Chiang, C. Baumgarten, Ralf Hertenberger, S. Yoneyama, C. A. Miller, Valeria Muccifora, E. Steffens, G. Gavrilov, B. Krauss, C. Scarlett, Wolfgang Lorenzon, J. Ely, K. Königsmann, V. Baturin, V. A. Kozlov, M. Ehrenfried, S. Potashov, E. De Sanctis, Franco Garibaldi, H. Zohrabian, W.H.A. Hesselink, R. De Leo, A. Fechtchenko, D. Veretennikov, G. Elbakian, Erika Garutti, S. Bernreuther, M. Bouwhuis, A. Airapetian, H. Böttcher, Michael Tytgat, A. Andrus, S. Taroian, A. Elalaoui-Moulay, Frank Ellinghaus, A. Borissov, P. Di Nezza, P. Liebing, E. R. Kinney, M. Contalbrigo, A. Schwind, Martin Raithel, E. C. Aschenauer, Y. Naryshkin, L. Felawka, V. Shutov, U. Elschenbroich, I. Sanjiev, G. Orlandi, K. P. Schüler, Naomi C R Makins, D. Gaskell, A. Hillenbrand, G. P. Capitani, E. Avetissian, Nicola Bianchi, O. Mikloukho, P. Bailey, U. Stosslein, L. Lagamba, Z. Akopov, Y. Miyachi, P. Zupranski, J. Wendland, D. Hasch, D. H. Potterveld, R. Fabbri, T. A. Shibata, G. Gapienko, R.O. Avakian, N. Meyners, G. Rosner, E. Devitsin, K. Sinram, H. Ohsuga, L. De Nardo, V. Gharibyan, A. Rostomyan, A. R. Reolon, A. Avetissian, J. Volmer, J. J. M. Steijger, Michael Düren, K. Hafidi, Y. Holler, M. C. Simani, A. Reischl, G. Ciullo, Christian Schill, Eugenio Nappi, M. Hartig, T. Wise, M. Beckmann, L. Lapikás, Jeffrey Brack, W. Haeberli, Klaus Rith, D. Heesbeen, G. van der Steenhoven, T. Lindemann, I.A. Savin, G.R. Court, Andreas Schäfer, and W.-D. Nowak
Subjects: Physics, HERMES experiment, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Hyperon, Lambda, Lambda baryon, Polarization (waves), 01 natural sciences, Particle identification, Nuclear physics, Transverse plane, Light cone, 0103 physical sciences, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract: The HERMES experiment has measured the transverse polarization of Lambda and {ovr Lambda} hyperons produced inclusively in quasireal photoproduction at a positron beam energy of 27.6 GeV. The transverse polarization P{sub n}{sup Lambda} of the Lambda hyperon is found to be positive while the observed {ovr Lambda} polarization is compatible with zero. The values averaged over the kinematic acceptance of HERMES are P{sub n}{sup Lambda} =0.078 {+-} 0.006(stat) {+-} 0.012(syst) and P{sub n}{sup {ovr Lambda}} = -0.025 {+-} 0.015(stat) {+-} 0.018(syst) for Lambda and {ovr Lambda}, respectively. The dependences of P{sub n}{sup Lambda} and P{sub n}{sup {ovr Lambda}} on the fraction zeta of the beam's light-cone momentum carried by the hyperon and on the hyperon's transverse momentum p{sub T} were investigated. The measured Lambda polarization rises linearly with p{sub T} and exhibits a different behavior for low and high values of zeta, which approximately correspond to the backward and forward regions in the center-of-mass frame of the gamma*N reaction.
Published: 2007

34. Simple parameterization of nuclear attenuation data

Author: Z. Akopov, L. Grigoryan, and N. Akopov
Subjects: HERMES experiment, Physics, Condensed Matter::Quantum Gases, Nuclear and High Energy Physics, Meson, High Energy Physics::Lattice, Nuclear Theory, Hadron, FOS: Physical sciences, Multiplicity (mathematics), Deep inelastic scattering, Particle identification, Nuclear physics, Baryon, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), High Energy Physics::Experiment, Atomic physics, Nucleon, Nuclear Experiment
Abstract: Based on the semi-inclusive deep inelastic scattering data obtained by the HERMES experiment on deuterium, nitrogen and krypton nuclei, it is shown that a ratio of multiplicities on nucleus and deuterium (per nucleon) for given hadron R{sub M}{sup h} can be parametrized in a form of a linear polynomial a{sub 11}+{tau}a{sub 12}, where {tau} is the formation time, which depends on the energy of the virtual photon {nu} and fraction of that energy z carried by the final hadron. Three widely known parametrizations for {tau} were used for the performed fit. The fit parameters a{sub 11} and a{sub 12} do not depend on {nu} and z.
Published: 2007

35. Precise determination of the spin structure function g(1) of the proton, deuteron, and neutron

Author: L. A. Linden-Levy, W.-D. Nowak, V. A. Gapienko, P. Zupranski, J. Streit, L. Felawka, I.A. Savin, N. Meyners, G. Rosner, W. Augustyniak, Shan Wang, G. P. Capitani, H. Böttcher, Andreas Schäfer, N. Bianchi, L. Rubacek, L. Lapikás, D. Veretennikov, G. Schnell, A. Funel, A. Nagaitsev, G. van der Steenhoven, A. Osborne, Salvatore Frullani, U. Stosslein, H. Ohsuga, Arne Vandenbroucke, L. Lagamba, Z. Akopov, Riccardo Fabbri, J. G. Rubin, P. F. Dalpiaz, Y. Naryshkin, Hidekazu Tanaka, G. Iarygin, P. Tait, Morgan Murray, T. A. Shibata, R.O. Avakian, Tetsuya Hasegawa, F. Giordano, A. Rostomyan, A. R. Reolon, Tsutomu Kobayashi, Y. Salomatin, M. Contalbrigo, A. Avetissian, P. Lenisa, A. Trzcinski, H. E. Jackson, H. Marukyan, N. Akopov, V. G. Krivokhijine, A. Airapetian, H. P. Blok, Y. X. Ye, M. Statera, A. Brull, B. Marianski, Martin Raithel, E. Devitsin, Wolfgang Lorenzon, E. C. Aschenauer, V. Shutov, A. Kisselev, B. Q. Ma, K. Garrow, Ivana Hristova, Hasko Stenzel, M. Capiluppi, C. Vogel, B. Hommez, C. Weiskopf, Alessandra Fantoni, M. Hoek, I. Sanjiev, G. Gapienko, F. Stinzing, J. Stewart, V. A. Kozlov, D. Reggiani, M. Ehrenfried, K. Rith, R. De Leo, P. E. Reimer, V. A. Korotkov, Michael Tytgat, Naomi C R Makins, R. Perez-Benito, B. Tchuiko, M. Kopytin, B. Maiheu, J. Dreschler, V. Vikhrov, M. Hartig, M. Demey, O. Grebeniouk, M. Stancari, Wouter Deconinck, P. Di Nezza, S. Taroian, P. Liebing, J. Lu, I. M. Gregor, Andrey V. Izotov, A. Jgoun, S. Yen, C. Shearer, B. Seitz, A. Borissov, Valeria Muccifora, C. Riedl, Ralf Kaiser, U. Elschenbroich, W.H.A. Hesselink, Y. Van Haarlem, M. Diefenthaler, E. Steffens, J. Seele, P. B. van der Nat, K. P. Schüler, E. De Sanctis, T. Michler, G. Elbakian, Franco Garibaldi, A. Hillenbrand, G. Gavrilov, H. Guler, A. Borysenko, A. Gute, A. Andrus, Eugenio Nappi, V. Mexner, E. Avetissian, N. Pickert, O. Mikloukho, Dirk Ryckbosch, M. Negodaev, S. Lu, Adel Terkulov, C. A. Miller, Y. Gärber, D. Gabbert, Y. J. Mao, P. Kravchenko, F. Masoli, T. Keri, J. J. M. Steijger, Michael Düren, A. Elalaoui-Moulay, Frank Ellinghaus, B. Zihlmann, E. R. Kinney, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, S. Belostotski, V. Bryzgalov, K. Sinram, L. De Nardo, Zhenyu Ye, V. Gharibyan, A. Reischl, B. Krauss, G. Ciullo, Y. Holler, A. Ivanilov, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education
Subjects: Physics, HERMES experiment, Nuclear and High Energy Physics, Proton, FOS: Physical sciences, 14.20.Dh, 13.88.+e, 13.60.Hb, 13.60.−r, HERA, Inelastic scattering, High Energy Physics - Experiment, NO, Nuclear physics, High Energy Physics - Experiment (hep-ex), Deuterium, High Energy Physics::Experiment, Neutron, ddc:530, Atomic physics, Nuclear Experiment, Nucleon, Spin-½
Abstract: Precise measurements of the spin structure functions of the proton $g_1^p(x,Q^2)$ and deuteron $g_1^d(x,Q^2)$ are presented over the kinematic range $0.0041 \leq x \leq 0.9$ and $0.18 $ GeV$^2$ $\leq Q^2 \leq 20$ GeV$^2$. The data were collected at the HERMES experiment at DESY, in deep-inelastic scattering of 27.6 GeV longitudinally polarized positrons off longitudinally polarized hydrogen and deuterium gas targets internal to the HERA storage ring. The neutron spin structure function $g_1^n$ is extracted by combining proton and deuteron data. The integrals of $g_1^{p,d}$ at $Q^2=5$ GeV$^2$ are evaluated over the measured $x$ range. Neglecting any possible contribution to the $g_1^d$ integral from the region $x \leq 0.021$, a value of $0.330 \pm 0.011\mathrm{(theo.)}\pm0.025\mathrm{(exp.)}\pm 0.028$(evol.) is obtained for the flavor-singlet axial charge $a_0$ in a leading-twist NNLO analysis.
Published: 2007

36. Beam-charge azimuthal asymmetry and deeply virtual Compton scattering

Author: A. Airapetian, A. Reischl, L. Lagamba, C. Shearer, B. Seitz, Z. Akopov, Shan Wang, H. Ohsuga, Klaus Rith, U. Elschenbroich, F. Stinzing, P. B. van der Nat, H. Y. Lu, A. Borissov, V. A. Gapienko, A. Nagaitsev, S. Frullani, G. Ciullo, M. Demey, C. A. Miller, N. Pickert, Dirk Ryckbosch, A. Rostomyan, A. R. Reolon, A. Avetissian, P. F. Dalpiaz, V. A. Korotkov, G. Iarygin, I. M. Gregor, R. Seidl, Hidekazu Tanaka, M. Stancari, M. Beckmann, A. Elalaoui-Moulay, Frank Ellinghaus, W.-D. Nowak, E. R. Kinney, M. Statera, A. Laziev, P. E. Reimer, K. Garrow, N. Akopov, L. Rubacek, Andrey V. Izotov, M. Bouwhuis, H. Böttcher, V. A. Kozlov, J. Seele, Valeria Muccifora, H. Marukyan, A. Osborne, Y. Naryshkin, Y. X. Ye, G. Gapienko, A. Hillenbrand, G. Elbakian, J. Volmer, Alessandra Fantoni, A. Funel, M. Hoek, A. Ivanilov, J. Stewart, K. P. Schüler, P. Zupranski, Y. J. Mao, P. Tait, B. Maiheu, A. Brull, B. Tchuiko, M. Kopytin, M. Contalbrigo, Tsutomu Kobayashi, L. Felawka, M. Amarian, W. Augustyniak, A. Andrus, Martin Raithel, Eugenio Nappi, E. De Sanctis, T. Michler, Y. Salomatin, S. Lu, E. C. Aschenauer, J. J. M. Steijger, M. Negodaev, Michael Düren, G. van der Steenhoven, V. Shutov, B. Krauss, G. P. Capitani, Adel Terkulov, I. Sanjiev, F. Masoli, Naomi C R Makins, Michael Tytgat, E. Avetissian, D. Balin, Nicola Bianchi, O. Mikloukho, W.H.A. Hesselink, G. Schnell, T. Chen, D. Gaskell, A. Jgoun, B. Q. Ma, H. E. Jackson, M. Hartig, N. Meyners, G. Rosner, L. A. Linden-Levy, K. Oganessyan, Y. Holler, S. Taroian, A. Borysenko, V. G. Krivokhijine, M. Ehrenfried, B. Marianski, J. Lu, C. Vogel, S. Yen, P. Lenisa, R. De Leo, Rezo Shanidze, A. Trzcinski, Ralf Kaiser, S. Belostotski, V. Bryzgalov, Wouter Deconinck, P. Di Nezza, F. Garibaldi, P. Liebing, E. Steffens, J. Dreschler, G. Gavrilov, V. Vikhrov, K. Sinram, L. De Nardo, Zhenyu Ye, Manuella Vincter, Hasko Stenzel, M. Capiluppi, L. Lapikás, I.A. Savin, J. G. Rubin, V. Gharibyan, V. Mexner, K. Hafidi, Morgan Murray, Y. Van Haarlem, B. Zihlmann, P. Bailey, T. A. Shibata, Cynthia Marie Hadjidakis, Y. Miyachi, R.O. Avakian, Andreas Schäfer, J. Wendland, W. Sommer, D. Hasch, D. H. Potterveld, E. Devitsin, A. Kisselev, Arne Vandenbroucke, Riccardo Fabbri, D. Reggiani, O. Grebeniouk, C. Riedl, H. P. Blok, Wolfgang Lorenzon, Ivana Hristova, B. Hommez, (Astro)-Particles Physics, and Photo Conversion Materials
Subjects: HERMES experiment, Elastic scattering, Physics, Nuclear and High Energy Physics, Particle physics, Photon, Scattering, media_common.quotation_subject, High Energy Physics::Phenomenology, Compton scattering, FOS: Physical sciences, DESY, HERA, 13.60.Fz Elastic and Compton scattering, 14.20.Dh, 24.85.+p, Asymmetry, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), ddc:530, High Energy Physics::Experiment, Nuclear Experiment, media_common
Abstract: The first observation of an azimuthal cross section asymmetry with respect to the charge of the incoming lepton beam is reported from a study of hard exclusive electroproduction of real photons. The data have been accumulated by the HERMES experiment at DESY, in which the HERA 27.6 GeV electron or positron beam scattered off an unpolarized hydrogen gas target. The observed asymmetry is attributed to the interference between the Bethe-Heitler process and the deeply virtual Compton scattering (DVCS) process. The interference term is sensitive to DVCS amplitudes, which provide the most direct access to generalized parton distributions. © 2007 The American Physical Society.
Published: 2007

37. Beam-spin asymmetries in the azimuthal distribution of pion electroproduction

Author: V. A. Korotkov, Wouter Deconinck, V. Mexner, J. Lu, S. Yen, B. Zihlmann, G. Elbakian, Y. Miyachi, H. Guler, Ralf Kaiser, B. Hommez, A. Nagaitsev, A. Borissov, M. Demey, G. Iarygin, H. Marukyan, E. Steffens, Dirk Ryckbosch, Hasko Stenzel, A. Airapetian, P. Lenisa, I.A. Savin, I. M. Gregor, V. Kozlov, A. Brull, G. Gavrilov, J. G. Rubin, A. Andrus, A. Trzcinski, B. Marianski, K. Sinram, L. De Nardo, T. Keri, Tsutomu Kobayashi, Y. J. Mao, P. Kravchenko, O. Grebeniouk, A. Elalaoui-Moulay, Frank Ellinghaus, E. R. Kinney, S. Lu, Y. Naryshkin, M. Negodaev, G.P. Capitani, M. Statera, S. Frullani, F. Stinzing, H. E. Jackson, V. G. Krivokhijine, Andreas Schäfer, N. Pickert, L. Felawka, M. Amarian, H. P. Blok, A. R. Reolon, T. A. Shibata, Adel Terkulov, C. Vogel, A. Funel, W.H.A. Hesselink, V. Muccifora, V. Vikhrov, J. J. M. Steijger, Michael Düren, Michael Tytgat, Y. Salomatin, Wolfgang Lorenzon, M. Stancari, P. E. Reimer, L. Lagamba, P. Di Nezza, P. Bailey, G. van der Steenhoven, C. A. Miller, Arne Vandenbroucke, P. Zupranski, Morgan Murray, R.O. Avakian, L. Rubacek, Riccardo Fabbri, B. Krauss, S. Taroian, K. P. Schüler, A. Fantoni, Ivana Hristova, H. Avakian, P.F. Dalpiaz, B. Q. Ma, A. Borysenko, F. Giordano, Alessandro Bacchetta, W. Augustyniak, M. Contalbrigo, E. Devitsin, O. Mikloukho, M. Ehrenfried, N. Meyners, Martin Raithel, W.-D. Nowak, R. De Leo, J. Stewart, K. Garrow, G. Rosner, E. C. Aschenauer, A. Kisselev, V. Shutov, A. Osborne, R. Seidl, E. Avetisyan, E. De Sanctis, T. Michler, Klaus Rith, V. Gharibyan, K. Oganessyan, I. Sanjiev, H. Böttcher, Naomi C R Makins, J. Streit, F. Masoli, S. Belostotski, D. Reggiani, M. Hartig, V. Bryzgalov, F. Garibaldi, C. Hadjidakis, P. Tait, J. Dreschler, M. Capiluppi, P. Liebing, Andrey V. Izotov, Z. Akopov, D. Hasch, Z. Ye, Hidekazu Tanaka, A. Jgoun, Y. Van Haarlem, C. Riedl, G. Gapienko, Shan Wang, H. Ohsuga, A. Rostomyan, A. Avetissian, K. Hafidi, M. Diefenthaler, J. Seele, A. Hillenbrand, A. Ivanilov, A. Reischl, Y. Holler, G. Ciullo, Tetsuya Hasegawa, V. A. Gapienko, N. Bianchi, R. Perez-Benito, B. Maiheu, C. Shearer, B. Seitz, E. Nappi, U. Elschenbroich, L. Lapikás, P. B. van der Nat, Y. X. Ye, L. A. Linden-Levy, M. Hoek, G. Schnell, B. Tchuiko, M. Kopytin, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education
Subjects: Nuclear and High Energy Physics, Meson, Hadron, FOS: Physical sciences, Virtual particle, Inelastic scattering, 01 natural sciences, 7. Clean energy, 24.85.+p, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, 13.88.+e, 0103 physical sciences, ddc:530, SDG 7 - Affordable and Clean Energy, 010306 general physics, Nuclear Experiment, 13.60.-r, Physics, 010308 nuclear & particles physics, 13.87.Fh, 14.20.Dh, HERA, Science General, Scattering amplitude, Physics::Accelerator Physics, High Energy Physics::Experiment, Dimensionless quantity
Abstract: A measurement of the beam-spin asymmetry in the azimuthal distribution of pions produced in semi-inclusive deep-inelastic scattering off protons is presented. The measurement was performed using the HERMES spectrometer with a hydrogen gas target and the longitudinally polarized 27.6 GeV positron beam of HERA. The sinusoidal amplitude of the dependence of the asymmetry on the angle ϕ of the hadron production plane around the virtual photon direction relative to the lepton scattering plane was measured for π + π + , π − π − and π 0 π 0 mesons. The dependence of this amplitude on the Bjorken scaling variable and on the pion fractional energy and transverse momentum is presented. The results are compared to theoretical model calculations.
Published: 2007

38. Double-hadron leptoproduction in the nuclear medium

Author: V. A. Korotkov, Klaus Rith, M. Stancari, J. Stewart, J. J. M. Steijger, A. Brüll, Michael Düren, G. Elbakian, D. Veretennikov, A. Airapetian, B. Zihlmann, K. Sinram, L. De Nardo, Zhenyu Ye, V. Gharibyan, W. Augustyniak, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, A. Funel, F. Giordano, P. Di Nezza, G. van der Steenhoven, M. Demey, Shan Wang, H. Ohsuga, A. Osborne, P. Liebing, R. Seidl, F. Stinzing, Hasko Stenzel, V. A. Gapienko, I. M. Gregor, G. Iarygin, M. Capiluppi, P. Lenisa, L. A. Linden-Levy, H. Böttcher, Michael Tytgat, A. Trzcinski, W.H.A. Hesselink, W.-D. Nowak, Tsutomu Kobayashi, A. Borysenko, H. Marukyan, J. G. Rubin, A. Rostomyan, A. Avetissian, S. Taroian, L. Lapikás, Dirk Ryckbosch, B. Hommez, Frank Ellinghaus, J. Streit, S. Lu, Adel Terkulov, G. Gapienko, I.A. Savin, E. R. Kinney, O. Grebeniouk, C. Riedl, C. Vogel, Salvatore Frullani, P. Tait, P. Bailey, L. Lagamba, H. Guler, Z. Akopov, Y. Naryshkin, P. F. Dalpiaz, Eugenio Nappi, A. Borissov, V. Vikhrov, A. R. Roelon, J. Dreschler, Hidekazu Tanaka, R. Perez-Benito, B. Maiheu, A. Andrus, H. E. Jackson, Andreas Schäfer, H. P. Blok, M. Negodaev, Morgan Murray, A. Jgoun, B. Krauss, Y. Van Haarlem, B. Marianski, Wolfgang Lorenzon, Tetsuya Hasegawa, Valeria Muccifora, Ivana Hristova, Y. Salomatin, K. P. Schüler, S. Belostotski, P. Zupranski, B. Q. Ma, V. Bryzgalov, M. Ehrenfried, R. De Leo, E. Avetissian, Nicola Bianchi, O. Mikloukho, Arne Vandenbroucke, N. Meyners, G. Rosner, Riccardo Fabbri, I. Sanjiev, K. Garrow, V. A. Kozlov, L. Felawka, M. Amarian, A. Nagaitsev, G. P. Capitani, G. Schnell, N. Akopov, Y. J. Mao, P. Kravchenko, V. G. Krivokhijine, F. Masoli, P. E. Reimer, M. Contalbrigo, Y. X. Ye, Martin Raithel, E. C. Aschenauer, V. Shutov, C. Shearer, B. Seitz, Naomi C R Makins, U. Elschenbroich, T. Keri, P. B. van der Nat, M. Hartig, J. Lu, Alessandra Fantoni, Wouter Deconinck, S. Yen, M. Hoek, K. A. Griffioen, Ralf Kaiser, B. Tchuiko, M. Kopytin, E. Steffens, G. Gavrilov, V. Mexner, T. A. Shibata, R.O. Avakian, A. Ivanilov, A. Reischl, E. Devitsin, A. Kisselev, G. Ciullo, D. Reggiani, Y. Holler, E. De Sanctis, T. Michler, Franco Garibaldi, M. Diefenthaler, J. Seele, A. Hillenbrand, N. Pickert, C. A. Miller, A. Elalaoui-Moulay, M. Statera, Andrey V. Izotov, L. Rubacek, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education
Subjects: Particle physics, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, chemistry.chemical_element, Inelastic scattering, 25.30.Rw, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Xenon, ddc:550, 13.60.−r, 13.87.Fh, 25.75.Gz, Nuclear Experiment, Physics, Scattering, High Energy Physics::Phenomenology, Krypton, HERA, Nuclear matter, Deep inelastic scattering, chemistry, Deuterium, High Energy Physics::Experiment
Abstract: Physical review letters 96, 162301 (2006). doi:10.1103/PhysRevLett.96.162301, Published by APS, College Park, Md.
Published: 2006

39. Longitudinal spin transfer to the Lambda hyperon in semiinclusive deep-inelastic scattering

Author: B. Hommez, B. Marianski, K. Sinram, L. De Nardo, A. Osborne, B. Krauss, Zhenyu Ye, Y. Van Haarlem, A. Borissov, V. Gharibyan, K. Hafidi, R. Seidl, P. E. Reimer, M. Bouwhuis, H. Böttcher, M. Diefenthaler, Morgan Murray, G. Iarygin, J. Seele, B. Zihlmann, V. Vikhrov, Manuella Vincter, A. Hillenbrand, Houbing Lu, P. Tait, J. Dreschler, A. Andrus, Cynthia Marie Hadjidakis, Y. Miyachi, J. Wendland, W. Sommer, M. Demey, M. Negodaev, D. Hasch, D. H. Potterveld, Dirk Ryckbosch, H. Marukyan, S. Belostotski, V. Bryzgalov, P. Bailey, I. M. Gregor, Y. Salomatin, Tsutomu Kobayashi, W. Augustyniak, M. Statera, Arne Vandenbroucke, Riccardo Fabbri, C. Vogel, B. Q. Ma, H. P. Blok, M. Beckmann, M. Ehrenfried, R. De Leo, Wolfgang Lorenzon, Andrey V. Izotov, Klaus Rith, J. J. M. Steijger, Michael Düren, T. A. Shibata, V. A. Korotkov, R.O. Avakian, A. Elalaoui-Moulay, Frank Ellinghaus, H. Ohsuga, Ivana Hristova, E. R. Kinney, M. Stancari, A. Jgoun, E. Devitsin, C. Riedl, Y. Naryshkin, Michael Tytgat, H. E. Jackson, A. Kisselev, V. G. Krivokhijine, A. Brüll, P. Lenisa, A. Trzcinski, N. Pickert, D. Reggiani, W.-D. Nowak, G. Elbakian, T. Chen, S. Taroian, C. A. Miller, Eugenio Nappi, S. I. Manaenkov, A. Nagaitsev, K. Oganessyan, A. Rostomyan, Salvatore Frullani, A. Funel, A. R. Reolon, A. Avetissian, G. van der Steenhoven, P. F. Dalpiaz, A. Borysenko, G. Gapienko, K. P. Schüler, I.A. Savin, Andreas Schäfer, E. De Sanctis, T. Michler, Franco Garibaldi, C. Shearer, B. Seitz, B. Maiheu, E. Avetissian, D. Balin, Nicola Bianchi, N. Akopov, O. Mikloukho, U. Elschenbroich, P. B. van der Nat, Y. J. Mao, P. Kravchenko, V. A. Gapienko, P. Di Nezza, P. Liebing, F. Masoli, J. G. Rubin, A. Laziev, H. C. Chiang, Song-Ming Wang, Y. X. Ye, Alessandra Fantoni, M. Hoek, B. Tchuiko, M. Kopytin, T. Keri, Wouter Deconinck, V. Mexner, Hidekazu Tanaka, K. Garrow, V. A. Kozlov, P. Zupranski, L. Lagamba, Z. Akopov, N. Meyners, J. Lu, G. Rosner, S. Yen, Ralf Kaiser, A. Airapetian, E. Steffens, F. Stinzing, G. Gavrilov, Xian Chen, J. Volmer, A. Ivanilov, L. Felawka, M. Amarian, X. R. Lu, M. Contalbrigo, G. P. Capitani, Martin Raithel, E. C. Aschenauer, G. Schnell, V. Shutov, I. Sanjiev, Naomi C R Makins, M. Hartig, A. Reischl, G. Ciullo, L. Rubacek, O. Grebeniouk, L. A. Linden-Levy, Y. Holler, L. Lapikás, J. Stewart, W.H.A. Hesselink, Valeria Muccifora, S. Lu, Adel Terkulov, Hasko Stenzel, M. Capiluppi, (Astro)-Particles Physics, and Photo Conversion Materials
Subjects: HERMES experiment, Nuclear and High Energy Physics, Particle physics, Lambda baryon, Lambda, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Positron, 13.88.+e, 0103 physical sciences, ddc:530, 13.60.−r, 13.60.Rj, SDG 7 - Affordable and Clean Energy, 010306 general physics, Physics, 010308 nuclear & particles physics, Scattering, Hyperon, HERA, Deep inelastic scattering, Physics::Accelerator Physics, High Energy Physics::Experiment
Abstract: The transfer of polarization from a high-energy positron to a {lambda}{sup 0} hyperon produced in semiinclusive deep-inelastic scattering has been measured. The data have been obtained by the HERMES experiment at DESY using the 27.6 GeV longitudinally polarized positron beam of the HERA collider and unpolarized gas targets internal to the positron (electron) storage ring. The longitudinal spin-transfer coefficient is found to be D{sub LL{sup '}}{sup {lambda}}=0.11{+-}0.10(stat){+-}0.03(syst) at an average fractional energy carried by the {lambda}{sup 0} hyperon =0.45. The dependence of D{sub LL{sup '}}{sup {lambda}} on both the fractional energy z and the fractional longitudinal momentum x{sub F} is presented.
Published: 2006

40. Measurement of the tensor structure function b1 of the deuteron

Author: M. Vogt, H. Ohsuga, G. Gapienko, M. C. Simani, A. Rostomyan, A. R. Reolon, A. Avetissian, A. Tkabladze, B. D. Fox, G. Schnell, P. E. Reimer, M. Henoch, K. Oganessyan, Hidekazu Tanaka, H. E. Jackson, V. G. Krivokhijine, Gharibyan, T. A. Shibata, R.O. Avakian, E. Devitsin, W. Augustyniak, Erika Garutti, M. Stancari, U. Stosslein, L. Lagamba, Z. Akopov, J. Seele, S. Bernreuther, Shutov, Korotkov, A. Brull, B. Seitz, B. Hommez, J. Wilbert, Arne Vandenbroucke, Riccardo Fabbri, Di Nezza P, Muccifora, Michael Tytgat, M. Demey, Gapienko, I. M. Gregor, Alessandra Fantoni, M. Hoek, Y. Holler, S. Taroian, G. Graw, A. Andrus, W.-D. Nowak, Klaus Rith, D. Heesbeen, Mexner, G. Iarygin, B. Tchuiko, M. Kopytin, M. Negodaev, A. Nass, P. Bailey, U. Elschenbroich, H. Marukyan, A. Airapetian, A. Kisselev, L. Felawka, M. Amarian, A. Borissov, De Leo R, G. P. Capitani, M. Bouwhuis, L. G. Greeniaus, F. Stinzing, K. Hafidi, A. Laziev, H. Böttcher, B. Maiheu, C. Weiskopf, D. Reggiani, A. Jgoun, I.A. Savin, A. Hillenbrand, A. Fechtchenko, Y. X. Ye, P. Zupranski, P. Lenisa, A. Trzcinski, J. Dreschler, A. Elalaoui-Moulay, Frank Ellinghaus, B. Marianski, J. Volmer, A. Ivanilov, P. F. Dalpiaz, E. R. Kinney, N. Meyners, P. Tait, G. Rosner, V. V. Ammosov, F. Garibaldi, K. P. Schüler, De Sanctis E, K. Garrow, Y. Salomatin, H. P. Blok, E. Avetissian, B. Zihlmann, D. Balin, Nicola Bianchi, Y. Naryshkin, O. Mikloukho, Ralf Hertenberger, Wolfgang Lorenzon, J. G. Rubin, Hasko Stenzel, A. Reischl, B. Q. Ma, H. C. Chiang, M. Ehrenfried, G. Ciullo, Christian Schill, Bryzgalov, Houbing Lu, Eugenio Nappi, S. Potashov, L. Rubacek, D. H. Potterveld, Y. J. Mao, R. Seidl, M. Contalbrigo, Manuella Vincter, Martin Raithel, E. C. Aschenauer, De Nardo L, van der Steenhoven G, S. Belostotski, Kozlov, M. Hartig, I. Sanjiev, Naomi C R Makins, J. Stewart, S. Frullani, O. Grebeniouk, C. Riedl, P. Liebing, J. Lu, M. Beckmann, S. Yen, C. A. Miller, Ralf Kaiser, E. Steffens, G. Gavrilov, Vikhrov, Baturin, B. Krauss, L. A. Linden-Levy, N. Pickert, Dirk Ryckbosch, van der Nat Pb, S. Lu, M. Statera, Adel Terkulov, Andrey V. Izotov, D. Gaskell, L. Lapikás, Jeffrey Brack, Katerina Lipka, C. Vogel, G. Elbakian, J. J. M. Steijger, Michael Düren, Y. Miyachi, J. Wendland, D. Hasch, K. Sinram, Zhenyu Ye, C. Shearer, T. Chen, A. Nagaitsev, Michel Vetterli, N. Akopov, F. Masoli, Rezo Shanidze, Andreas Schäfer, W.H.A. Hesselink, A. Borysenko, (Astro)-Particles Physics, and Photo Conversion Materials
Subjects: HERMES experiment, Particle physics, media_common.quotation_subject, FOS: Physical sciences, General Physics and Astronomy, Spin structure, Inelastic scattering, Asymmetry, High Energy Physics - Experiment, 14.65.−q, Nuclear physics, High Energy Physics - Experiment (hep-ex), 13.88.+e, SDG 7 - Affordable and Clean Energy, Nuclear Experiment, media_common, Physics, 13.60.−r, 14.20.Dh, Scattering, Momentum transfer, HERA, Deep inelastic scattering, High Energy Physics::Experiment
Abstract: The \Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of \Hera. The use of a tensor polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry $\At$ and the tensor structure function $\bd$ for average values of the Bj��rken variable $0.01<< x>
Published: 2005

41. Subleading-twist effects in single-spin asymmetries in semi-inclusive deep-inelastic scattering on a longitudinally polarized hydrogen target

Author: P. Zupranski, P. Lenisa, L. Felawka, M. Amarian, Houbing Lu, A. Trzcinski, L. Lagamba, P. Di Nezza, C. Shearer, B. Seitz, E. Nappi, V. Muccifora, F. Masoli, S. Belostotski, G. Iarygin, V. Bryzgalov, A. Funel, G. van der Steenhoven, U. Elschenbroich, W.H.A. Hesselink, A. Borysenko, P. Bailey, G. Schnell, F. Garibaldi, N. Meyners, G. Rosner, Y. Salomatin, P. B. van der Nat, A. R. Reolon, Wouter Deconinck, H. Marukyan, Tsutomu Kobayashi, Andrey V. Izotov, J. Volmer, D. Hasch, P. E. Reimer, Hasko Stenzel, T. Chen, K. Hafidi, M. Negodaev, Z. Akopov, C. A. Miller, W. Augustyniak, M. Diefenthaler, A. Ivanilov, M. Contalbrigo, Martin Raithel, V. Mexner, S. Lu, G. Gapienko, Adel Terkulov, A. Fantoni, T. A. Shibata, Hidekazu Tanaka, E. C. Aschenauer, V. Shutov, V. A. Gapienko, R.O. Avakian, B. Q. Ma, I. Sanjiev, E. De Sanctis, T. Michler, B. Krauss, A. Nagaitsev, V. Gharibyan, A. Reischl, Dirk Ryckbosch, N. Bianchi, Naomi C R Makins, E. Devitsin, A. Kisselev, A. Osborne, T. Keri, D. Reggiani, M. Ehrenfried, H. E. Jackson, K. Garrow, V. G. Krivokhijine, A. Airapetian, V. A. Korotkov, J. Seele, J. Dreschler, R. De Leo, M. Demey, A. Hillenbrand, S. Frullani, A. Laziev, J. Lu, S. Yen, I. M. Gregor, F. Stinzing, L. Rubacek, A. Andrus, Michael Tytgat, Y. Holler, N. Pickert, Song-Ming Wang, N. Akopov, Ralf Kaiser, A. Elalaoui-Moulay, Frank Ellinghaus, S. Taroian, Y. X. Ye, G.P. Capitani, E. R. Kinney, E. Steffens, Y. J. Mao, H. Ohsuga, G. Elbakian, M. Hoek, Y. Naryshkin, G. Gavrilov, J. Stewart, B. Tchuiko, M. Kopytin, A. Rostomyan, A. Brüll, V. Vikhrov, A. Jgoun, Manuella Vincter, A. Avetissian, M. Statera, Y. Van Haarlem, C. Riedl, C. Vogel, Morgan Murray, R. Seidl, M. Bouwhuis, H. Böttcher, B. Maiheu, P. Tait, G. Ciullo, K. Sinram, L. De Nardo, Zhenyu Ye, B. Zihlmann, L. A. Linden-Levy, Y. Miyachi, J. Wendland, W. Sommer, D. H. Potterveld, L. Lapikás, M. Hartig, M. Capiluppi, P. Liebing, K. P. Schüler, B. Hommez, P.F. Dalpiaz, J. J. M. Steijger, Michael Düren, M. Stancari, D. Balin, O. Mikloukho, E. Avetissian, J. G. Rubin, A. Borissov, M. Beckmann, Klaus Rith, B. Marianski, C. Hadjidakis, I.A. Savin, Andreas Schäfer, W.-D. Nowak, Arne Vandenbroucke, Riccardo Fabbri, Alessandro Bacchetta, H. P. Blok, Wolfgang Lorenzon, Ivana Hristova, K. Oganessyan, V. Kozlov, O. Grebeniouk, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education
Subjects: Quark, Nuclear and High Energy Physics, Particle physics, Proton, Meson, Nuclear Theory, FOS: Physical sciences, Inelastic scattering, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, 13.60.-r, 13.88.+e, 14.20.Dh, 14.65.-q, 0103 physical sciences, SDG 14 - Life Below Water, 010306 general physics, Nuclear Experiment, Spin-½, Physics, 010308 nuclear & particles physics, Scattering, High Energy Physics::Phenomenology, Deep inelastic scattering, Physics::Accelerator Physics, High Energy Physics::Experiment
Abstract: Single-spin asymmetries in the semi-inclusive production of charged pions in deep-inelastic scattering from transversely and longitudinally polarized proton targets are combined to evaluate the subleading-twist contribution to the longitudinal case. This contribution is significantly positive for π + mesons and dominates the asymmetries on a longitudinally polarized target previously measured by Hermes . The subleading-twist contribution for π − mesons is found to be small.
Published: 2005

42. Search for an exoticS=−2,Q=−2baryon resonance at a mass near 1862 MeV in quasireal photoproduction

Author: Klaus Rith, A. Nagaitsev, A. Funel, C. Shearer, B. Seitz, B. Maiheu, G. van der Steenhoven, W. Augustyniak, A. Andrus, I.A. Savin, A. Borysenko, Andreas Schäfer, J. Seele, Morgan Murray, U. Elschenbroich, P. B. van der Nat, Salvatore Frullani, M. Negodaev, N. Akopov, P. Lenisa, A. Trzcinski, A. Hillenbrand, B. Krauss, P. E. Reimer, Wouter Deconinck, P. F. Dalpiaz, Alessandra Fantoni, M. Hoek, V. Mexner, V. A. Gapienko, V. A. Korotkov, B. Tchuiko, M. Kopytin, K. Sinram, L. De Nardo, Y. Van Haarlem, G. Iarygin, Zhenyu Ye, P. Bailey, M. Stancari, M. Beckmann, A. Elalaoui-Moulay, Frank Ellinghaus, E. R. Kinney, V. Gharibyan, K. Garrow, Y. J. Mao, R. Seidl, Tsutomu Kobayashi, H. Marukyan, M. Bouwhuis, H. Böttcher, Y. Naryshkin, B. Hommez, G. Gapienko, F. Masoli, V. A. Kozlov, Michael Tytgat, P. Tait, J. J. M. Steijger, Michael Düren, Houbing Lu, T. Keri, A. Borissov, S. Taroian, H. E. Jackson, Y. Salomatin, A. Laziev, G. Elbakian, K. Hafidi, S. Belostotski, V. G. Krivokhijine, V. Bryzgalov, A. Osborne, B. Q. Ma, M. Diefenthaler, B. Zihlmann, M. Ehrenfried, Y. X. Ye, S. Wang, T. A. Shibata, Eugenio Nappi, R.O. Avakian, Cynthia Marie Hadjidakis, Y. Miyachi, O. Grebeniouk, C. Riedl, R. De Leo, J. Wendland, W. Sommer, D. Hasch, E. Devitsin, D. H. Potterveld, A. Kisselev, D. Reggiani, L. Felawka, M. Amarian, Dirk Ryckbosch, P. Zupranski, J. Drechsler, A. Jgoun, G. P. Capitani, H. P. Blok, C. Vogel, G. Schnell, H. Ohsuga, Wolfgang Lorenzon, L. Lagamba, Z. Akopov, Ivana Hristova, V. Vikhrov, A. Rostomyan, A. R. Reolon, A. Avetissian, Manuella Vincter, N. Meyners, K. Oganessyan, G. Rosner, P. Di Nezza, Hidekazu Tanaka, P. Liebing, A. Airapetian, W.-D. Nowak, K. P. Schüler, E. De Sanctis, T. Michler, Franco Garibaldi, F. Stinzing, E. Avetissian, D. Balin, Nicola Bianchi, O. Mikloukho, J. G. Rubin, M. Statera, B. Marianski, Hasko Stenzel, M. Contalbrigo, M. Capiluppi, Andrey V. Izotov, Martin Raithel, E. C. Aschenauer, Arne Vandenbroucke, V. Shutov, Riccardo Fabbri, I. Sanjiev, S. Lu, Naomi C R Makins, Adel Terkulov, M. Hartig, A. Reischl, N. Pickert, T. Chen, F. Giordano, W.H.A. Hesselink, M. Demey, G. Ciullo, J. Lu, S. Yen, I. M. Gregor, C. A. Miller, Ralf Kaiser, Valeria Muccifora, E. Steffens, L. A. Linden-Levy, G. Gavrilov, L. Lapikás, J. Volmer, A. Ivanilov, L. Rubacek, Y. Holler, J. Stewart, and A. Brüll
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Resonance, Lambda baryon, 01 natural sciences, Baryon, Particle decay, Exotic baryon, 0103 physical sciences, Mass spectrum, Invariant mass, Atomic physics, 010306 general physics
Abstract: A search for an exotic baryon resonance with $S=\ensuremath{-}2$, $Q=\ensuremath{-}2$ has been performed in quasireal photoproduction on a deuterium target through the decay channel ${\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\Lambda}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}$. No evidence for a previously reported ${\ensuremath{\Xi}}^{--}(1860)$ resonance is found in the ${\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}$ invariant mass spectrum. An upper limit for the photoproduction cross section of 2.1 nb is found at the 90% confidence level. The photoproduction cross section for the ${\ensuremath{\Xi}}^{0}(1530)$ is found to be between 9 and 24 nb.
Published: 2005

43. Application of the Two-Scale Model to the HERMES Data on Nuclear Attenuation

Author: L. Grigoryan, N. Akopov, and Z. Akopov
Subjects: Physics, Particle physics, Photon, Physics and Astronomy (miscellaneous), Meson, Attenuation, Nuclear Theory, Hadron, FOS: Physical sciences, Virtual particle, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), High Energy Physics::Experiment, Multiplicity (chemistry), Nuclear Experiment, Engineering (miscellaneous), Scale model
Abstract: The Two-Scale Model and its improved version were used to perform the fit to the HERMES data for $\nu$ (the virtual photon energy) and z (the fraction of $\nu$ carried by hadron) dependencies of nuclear multiplicity ratios for $\pi^+$ and $\pi^-$ mesons electro-produced on two nuclear targets ($^{14}$N and $^{84}$Kr). The quantitative criterium $\chi ^2$ was used for the first time to analyse the results of the model fit to the nuclear multiplicity ratios data. The two-parameter's fit gives satisfactory agreement with the HERMES data. Best values of the parameters were then used to calculate the $\nu$- and $z$ - dependencies of nuclear attenuation for $\pi^0$, K$^+$, K$^-$ and $\bar{p}$ produced on $^{84}$Kr target, and also make a predictions for $\nu$, z and the Q$^2$ (the photon virtuality) - dependencies of nuclear attenuation data for those identified hadrons and nuclea, that will be published by HERMES.
Published: 2004

44. Flavor decomposition of the sea-quark helicity distributions in the nucleon from semiinclusive deep inelastic scattering

Author: P. Zupranski, N. Meyners, G. Rosner, A. Airapetian, A. Borissov, Hidekazu Tanaka, A. Nagaitsev, A. Tkabladze, M. Negodaev, M. Contalbrigo, B. Hommez, Salvatore Frullani, P. E. Reimer, R. Seidl, C. Shearer, V. A. Korotkov, M. Bouwhuis, Martin Raithel, E. C. Aschenauer, V. Shutov, A. Hillenbrand, G. Graw, M. Henoch, V. A. Kozlov, I. Sanjiev, H. Ohsuga, Michel Vetterli, B. D. Fox, B. Zihlmann, H. C. Chiang, S. Belostotski, J. Volmer, H. P. Blok, Erika Garutti, H. Böttcher, A. Ivanilov, B. Seitz, M. Statera, V. A. Gapienko, G. Orlandi, V. Bryzgalov, Wolfgang Lorenzon, Naomi C R Makins, G. Schnell, P. F. Dalpiaz, M. Stancari, D. Gaskell, N. Akopov, K. Königsmann, V. Baturin, U. Elschenbroich, L. Felawka, M. Amarian, A. Fechtchenko, Ralf Hertenberger, E. De Sanctis, V. Gharibyan, Franco Garibaldi, G. Iarygin, G. Elbakian, K. P. Schüler, Y. Holler, S. Bernreuther, Andrey V. Izotov, A. Elalaoui-Moulay, Frank Ellinghaus, P. B. van der Nat, E. R. Kinney, P. Bailey, P. Tait, G. P. Capitani, A. Schwind, Dirk Ryckbosch, Valeria Muccifora, W.H.A. Hesselink, H. Marukyan, E. Avetissian, Nicola Bianchi, O. Mikloukho, A. Rostomyan, A. R. Reolon, Y. Naryshkin, J. Franz, Michael Tytgat, S. Potashov, O. Grebeniouk, H. Zohrabian, U. Stosslein, L. Lagamba, M. C. Simani, A. Avetissian, Z. Akopov, F. Masoli, J. Visser, M. Vogt, V. Vikhrov, Manuella Vincter, J. Lu, S. Taroian, S. Yen, G. V. Ybeles Smit, C. A. Miller, L. G. Greeniaus, C. Weiskopf, A. Andrus, Katerina Lipka, H. E. Jackson, Ralf Kaiser, J. Seele, B. Krauss, V. G. Krivokhijine, P. Di Nezza, Alessandra Fantoni, J. Ely, A. Reischl, Y. Miyachi, L. Rubacek, M. Hoek, A. Jgoun, C. Scarlett, K. Hafidi, E. Steffens, P. Liebing, C. Baumgarten, G. Gapienko, G. Gavrilov, P. Lenisa, G. Ciullo, C. Vogel, C. Riedl, R. Fabbri, T. A. Shibata, K. Oganessyan, J. Wendland, Christian Schill, R.O. Avakian, A. Trzcinski, Adel Terkulov, B. Tchuiko, M. Kopytin, D. Hasch, A. Nass, D. Reggiani, V. Mexner, L. Lapikás, E. Devitsin, J. Stewart, V. V. Ammosov, A. Brüll, J. Wilbert, Y. Gärber, D. H. Potterveld, Y. Salomatin, Arne Vandenbroucke, R. Shanidze, M. Hartig, A. Laziev, W. Augustyniak, N. Pickert, M. Ehrenfried, K. Garrow, R. De Leo, B. Marianski, Jeffrey Brack, W.-D. Nowak, Eugenio Nappi, A. Kisselev, B. Maiheu, M. Beckmann, K. Sinram, L. De Nardo, J. J. M. Steijger, Michael Düren, G. van der Steenhoven, T. Lindemann, Klaus Rith, D. Heesbeen, I.A. Savin, Andreas Schäfer, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education
Subjects: Quark, Particle physics, Meson, High Energy Physics::Lattice, Nuclear Theory, Hadron, FOS: Physical sciences, General Physics and Astronomy, 13.60.–r, Inelastic scattering, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, 13.88.+e, Nuclear Experiment, 14.20.Dh, 14.65.–q, QC, Physics, High Energy Physics::Phenomenology, Quark model, Deep inelastic scattering, Baryon, High Energy Physics::Experiment
Abstract: Double-spin asymmetries of semi-inclusive cross sections for the production of identified pions and kaons have been measured in deep-inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with re-analyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data., Comment: 5 pages, 3 figures
Published: 2004

45. Electroproduction of Pseudoscalar Mesons on Nuclei at HERMES

Author: Z. Akopov
Subjects: Physics, Particle physics, Meson, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Deep inelastic scattering, Pseudoscalar, Nuclear physics, Positron, Pion, Deuterium, High Energy Physics::Experiment, Multiplicity (chemistry), Nuclear Experiment
Abstract: Results from unpolarized electroproduction of mesons at HERMES are presented, including production in a nuclear environment and its effect on the multiplicity of identified pions and kaons. The hadron attenuation, i.e. the reduction of the multiplicity on nuclei relative to that on deuterium has been measured as a function of two kinematic variables, using a 27.6 GeV positron beam. Also, results from electroproduction of neutral pions via the Primakoff mechanism are presented, using 12 GeV positron data.
Published: 2004

46. The HERMES Polarized Hydrogen and Deuterium Gas Target in the HERA Electron Storage Ring

Author: G. Graw, Y. Salomatin, V. A. Gapienko, N. Bianchi, V. A. Korotkov, K. Sinram, L. De Nardo, M. Ehrenfried, R. De Leo, B. Hommez, W. Haeberli, Y. Van Haarlem, R. Seidl, J. G. Rubin, L. Lapikás, M. Bouwhuis, H. Böttcher, L. Rubacek, J. Seele, P. Tait, Michael Tytgat, E. Avetissian, K. Garrow, H. Ohsuga, Dirk Ryckbosch, A. Airapetian, Klaus Rith, G. Elbakian, W. Augustyniak, S. Lu, D. Heesbeen, B. Zihlmann, L. A. Linden-Levy, S. Taroian, Adel Terkulov, H. E. Jackson, V. G. Krivokhijine, H. P. Blok, A. Borissov, Y. Miyachi, J. Wendland, C. Baumgarten, W. Sommer, A. Reischl, F. Stinzing, Wolfgang Lorenzon, B. Maiheu, A. Rostomyan, A. Avetissian, D. H. Potterveld, Z. Akopov, G. Iarygin, J. Stewart, A. Brüll, C. Hadjidakis, Bo-Qiang Ma, R. Mussa, Ivana Hristova, G. Schnell, C. A. Miller, P. Bailey, J. Wilbert, P. E. Reimer, Rezo Shanidze, M. Henoch, G. Gapienko, Arne Vandenbroucke, G. van der Steenhoven, V. Vikhrov, Manuella Vincter, A. Nagaitsev, Michel Vetterli, A. Fantoni, E. De Sanctis, V. Kozlov, A. Laziev, Riccardo Fabbri, M. Statera, Hidekazu Tanaka, D. Reggiani, W.H.A. Hesselink, A. Borysenko, G. Ciullo, K. P. Schüler, P.F. Dalpiaz, N. Koch, B. Braun, T. Kobayashi, N. Akopov, O. Grebeniouk, Z. Ye, Y. Mao, P. Lenisa, V. Gharibyan, J. J. M. Steijger, Michael Düren, A. Trzcinski, J. Volmer, M. Stancari, T. Wise, C. Schill, A. Jgoun, Y. X. Ye, A. Ivanilov, A. Fechtchenko, C. Vogel, D. Balin, O. Mikloukho, M. Beckmann, W.-D. Nowak, A. R. Reolon, C. Shearer, Hasko Stenzel, C. Riedl, L. Felawka, B. Seitz, M. Amarian, E. Nappi, K. Hafidi, V. Mexner, I.A. Savin, L. Lagamba, V. Muccifora, U. Elschenbroich, M. Demey, P. Zupranski, P. Di Nezza, H. Kolster, Y. Holler, K. Oganessyan, P. B. van der Nat, I. M. Gregor, N. Meyners, G. Rosner, A. Osborne, Ralf Hertenberger, T. A. Shibata, M. Hartig, G.P. Capitani, Andrey V. Izotov, R.O. Avakian, M. Hoek, D. Hasch, B. Marianski, G.R. Court, G. V. Ybeles Smit, M. Capiluppi, B. Tchuiko, M. Kopytin, A. Nass, S. Frullani, P. Liebing, N. Pickert, E. Devitsin, J. Lu, A. Kisselev, S. Yen, Ralf Kaiser, E. Steffens, A. Hillenbrand, G. Gavrilov, M. Contalbrigo, Martin Raithel, T. Chen, E. C. Aschenauer, V. Shutov, I. Sanjiev, Naomi C R Makins, H. Marukyan, Houbing Lu, S. Belostotski, A. Andrus, V. Bryzgalov, M. Negodaev, F. Garibaldi, Sihui Wang, A. Elalaoui-Moulay, Frank Ellinghaus, E. R. Kinney, Y. Naryshkin, B. Krauss, (Astro)-Particles Physics, and Photo Conversion Materials
Subjects: 29.25.Pj, Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Hydrogen, Atomic Physics (physics.atom-ph), chemistry.chemical_element, FOS: Physical sciences, 07.60.F, Electron, 01 natural sciences, Physics - Atomic Physics, NO, 07.77, 29.25.-t, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, 010306 general physics, Instrumentation, Physics, 67.65, 010308 nuclear & particles physics, DESY, HERA, Instrumentation and Detectors (physics.ins-det), Polarization (waves), 29.25.P, chemistry, Deuterium, Cathode ray, Atomic physics, Nucleon
Abstract: The HERMES hydrogen and deuterium nuclear-polarized gas targets have been in use since 1996 with the polarized electron beam of HERA at DESY to study the spin structure of the nucleon. Polarized atoms from a Stern-Gerlach Atomic Beam Source are injected into a storage cell internal to the HERA electron ring. Atoms diffusing from the center of the storage cell into a side tube are analyzed to determine the atomic fraction and the atomic polarizations. The atoms have a nuclear polarization, the axis of which is defined by an external magnetic holding field. The holding field was longitudinal during 1996-2000, and was changed to transverse in 2001. The design of the target is described, the method for analyzing the target polarization is outlined, and the performance of the target in the various running periods is presented. © 2004 Elsevier B.V. All rights reserved.
Published: 2004
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47. Evidence for a narrow |S|=1 baryon state at a mass of 1528 MeV in quasi-real photoproduction

Author: J. Stewart, A. Brüll, Ralf Hertenberger, W.H.A. Hesselink, J. Lu, S. Yen, K. Garrow, Y. Salomatin, Z. Ye, L. A. Linden-Levy, C. A. Miller, B. Hommez, Wouter Deconinck, C. Shearer, Ralf Kaiser, P. Zupranski, A. Elalaoui-Moulay, Frank Ellinghaus, E. Steffens, A. Jgoun, Ingrid-Maria Gregor, H. P. Blok, W. Augustyniak, G. Ciullo, E. R. Kinney, G. Gavrilov, U. Elschenbroich, B. Marianski, Wolfgang Lorenzon, J. Ely, V. Mexner, N. Meyners, G. Rosner, M. Ehrenfried, R. De Leo, A. Fantoni, A. Tkabladze, P. B. van der Nat, H. Y. Lu, M. Contalbrigo, B. D. Fox, Y. Naryshkin, Dirk Ryckbosch, B. Zihlmann, K. P. Schüler, Jeffrey Brack, Katerina Lipka, Martin Raithel, W.-D. Nowak, C. Riedl, T. Chen, E. C. Aschenauer, G. Schnell, P.F. Dalpiaz, V. Shutov, M. Vogt, I. Sanjiev, K. Hafidi, M. Statera, Hasko Stenzel, A. Kisselev, H. E. Jackson, Michael Tytgat, Naomi C R Makins, F. Masoli, E. Nappi, A. Nagaitsev, D. Gaskell, A. Airapetian, D. Balin, O. Mikloukho, A. Hillenbrand, G. Iarygin, S. Belostotski, E. De Sanctis, V. Gharibyan, V. Bryzgalov, V. G. Krivokhijine, S. Potashov, K. Oganessyan, J. Wilbert, H. Zohrabian, F. Garibaldi, A. Fechtchenko, Michel Vetterli, R. Seidl, A. Borissov, Arne Vandenbroucke, G. Graw, S. Taroian, M. Bouwhuis, H. Böttcher, P. Lenisa, A. R. Reolon, A. Laziev, Riccardo Fabbri, V. A. Gapienko, C. Vogel, A. Andrus, A. Trzcinski, D. Reggiani, F. Stinzing, N. Akopov, N. Bianchi, V. V. Ammosov, H. Marukyan, R. Shanidze, Y. X. Ye, P. E. Reimer, P. Tait, M. Negodaev, S. Frullani, X. R. Lu, Bo-Qiang Ma, V. Kozlov, L. Lapikás, B. Krauss, V. Muccifora, P. Liebing, Erika Garutti, U. Stosslein, M. Hoek, M. Henoch, T. A. Shibata, E. Avetissian, V. A. Korotkov, J. G. Rubin, N. Pickert, R.O. Avakian, Xun Chen, J. Seele, S. Bernreuther, O. Grebeniouk, Z. Akopov, E. Devitsin, B. Tchuiko, M. Kopytin, S. Lu, Hidekazu Tanaka, A. Nass, Adel Terkulov, V. Baturin, V. Vikhrov, Manuella Vincter, H. C. Chiang, G. Elbakian, P. Bailey, Andrey V. Izotov, G.P. Capitani, D. Hasch, B. Maiheu, Y. Mao, G. V. Ybeles Smit, L. G. Greeniaus, B. Seitz, C. Weiskopf, L. Felawka, M. Amarian, L. Lagamba, P. Di Nezza, G. Gapienko, M. C. Simani, Y. Miyachi, J. Wendland, D. H. Potterveld, H. Ohsuga, A. Rostomyan, A. Avetissian, K. Sinram, L. De Nardo, J. J. M. Steijger, Michael Düren, M. Stancari, A. Reischl, C. Schill, M. Beckmann, J. Volmer, A. Ivanilov, Y. Holler, G. van der Steenhoven, M. Hartig, A. Borysenko, W. Yu, I.A. Savin, Andreas Schäfer, Klaus Rith, D. Heesbeen, and L. Rubacek
Subjects: Nuclear and High Energy Physics, Particle physics, Nuclear Theory, FOS: Physical sciences, 01 natural sciences, NO, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, Invariant mass, 12.39.Mk, 13.60.-r, 13.60.Rj, 14.20.-c, 010306 general physics, Nuclear Experiment, Physics, Isovector, 010308 nuclear & particles physics, State (functional analysis), Pentaquark, Baryon, Deuterium, Exotic baryon, Mass spectrum, High Energy Physics::Experiment
Abstract: Evidence for a narrow baryon state is found in quasi-real photoproduction on a deuterium target through the decay channel p K^0_S --> p pi^+ pi^-. A peak is observed in the p K^0_S invariant mass spectrum at 1528 +/- 2.6 (stat) +/-2.1 (syst) MeV. Depending on the background model,the naive statistical significance of the peak is 4--6 standard deviations and its width may be somewhat larger than the experimental resolution of sigma=4.3 -- 6.2 MeV. This state may be interpreted as the predicted S=+1 exotic Theta^{+}(uuddbar(s)) pentaquark baryon. No signal for an hypothetical Theta^{++} baryon was observed in the pK^+ invariant mass distribution. The absence of such a signal indicates that an isotensor Theta is excluded and an isovector Theta is unlikely., 8 pages, 4 figures
Published: 2003

48. Q2Dependence of Nuclear Transparency for Exclusiveρ0Production

Author: I. Brunn, A. Kisselev, J. Wilbert, A. Nagaitsev, U. Stosslein, L. Lagamba, Z. Akopov, V. A. Korotkov, Michel Vetterli, A. Laziev, V. Gapienko, P. E. Reimer, M. Henoch, B. D. Fox, B. Zihlmann, Y. Miyachi, M. Stancari, T. Wise, J. Wendland, W. Augustyniak, G. van der Steenhoven, N. Akopov, G. Schnell, D. Hasch, K. Königsmann, V. Baturin, B. Hommez, M. Beckmann, D. H. Potterveld, H. P. Blok, Alessandra Fantoni, S. Tessarin, S. Yoneyama, T. Lindemann, K. Hafidi, H. Kolster, H. Ohsuga, G. Elbakian, G. Graw, Wolfgang Lorenzon, S. Bernreuther, A. Tkabladze, A. Elalaoui-Moulay, Frank Ellinghaus, Dirk Ryckbosch, R. Fabbri, B. Tchuiko, M. Kopytin, T. A. Shibata, A. Nass, S. Podiatchev, A. Rostomyan, R.O. Avakian, E. R. Kinney, A. R. Reolon, A. Avetissian, A. Jgoun, B. Seitz, A. Schwind, P. Lenisa, J. Seibert, K. Sinram, E. Devitsin, L. De Nardo, A. Trzcinski, G. Gapienko, O. Grebeniouk, P. B. van der Nat, D. Reggiani, M. Vogt, Y. Naryshkin, V. Gharibyan, V. V. Ammosov, K. Oganessyan, M. Ehrenfried, A. Hillenbrand, E. De Sanctis, V. Vikhrov, Manuella Vincter, Franco Garibaldi, R. De Leo, V. A. Kozlov, Klaus Rith, D. Heesbeen, M. Bouwhuis, J. J. M. Steijger, Michael Düren, L. G. Greeniaus, C. Weiskopf, H. Böttcher, H. E. Jackson, S. Belostotski, V. G. Krivokhijine, Eugenio Nappi, Erika Garutti, C. Baumgarten, A. Andrus, G. Iarygin, L. Felawka, I.A. Savin, B. Krauss, G. P. Capitani, H. Marukyan, R. Van de Vyver, C. Scarlett, G.R. Court, J. Franz, Andreas Schäfer, A. Terkulov, K. Negodaeva, M. Amarian, M. Hartig, S. Potashov, H. Zohrabian, Hidekazu Tanaka, U. Elschenbroich, A. Airapetian, P. Bailey, G. M. Urciuoli, P. Di Nezza, J. Stewart, P. Liebing, A. Brüll, Ralf Hertenberger, W.H.A. Hesselink, P. Zupranski, H. C. Chiang, N. Meyners, G. Rosner, L. Lapikás, K. P. Schüler, A. Borissov, E. Avetissian, Nicola Bianchi, O. Mikloukho, A. Reischl, W. Haeberli, G. Ciullo, Christian Schill, Salvatore Frullani, Valeria Muccifora, P. F. Dalpiaz, Y. Holler, Jeffrey Brack, M. C. Simani, J. Volmer, A. Fechtchenko, Michael Tytgat, S. Taroian, Y. Gärber, E. Thomas, R. Shanidze, M. Contalbrigo, Martin Raithel, E. C. Aschenauer, V. Shutov, M. Statera, I. Sanjiev, Andrey V. Izotov, G. Orlandi, Naomi C R Makins, C. A. Miller, J. Ely, D. Gaskell, F. Menden, S. Yen, Ralf Kaiser, E. Steffens, G. Gavrilov, F. Masoli, J. Visser, V. Mexner, and W.-D. Nowak
Subjects: HERMES experiment, Physics, Nuclear reaction, Particle physics, Meson, Nuclear Theory, Hadron, General Physics and Astronomy, Virtual particle, Coherence length, Nuclear physics, Nuclear transparency, High Energy Physics::Experiment, Nuclear Experiment, Nucleon
Abstract: Exclusive coherent and incoherent electroproduction of the rho(0) meson from H-1 and N-14 targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q(2)). The ratio of N-14 to H-1 cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q(2) is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency.
Published: 2003

49. Quark fragmentation to π±, π0, K±, p and p_bar in the nuclear environment

Author: R. Fabbri, Katerina Lipka, A. Fechtchenko, T. A. Shibata, M. Statera, K. P. Schüler, R.O. Avakian, E. Nappi, Dirk Ryckbosch, C. Shearer, C. Vogel, B. Seitz, E. Devitsin, O. Mikloukho, A. R. Reolon, J. Seele, S. Bernreuther, J. Wilbert, L. Lapikás, U. Elschenbroich, P. B. van der Nat, Adel Terkulov, Arne Vandenbroucke, H. E. Jackson, V. G. Krivokhijine, G. Gapienko, S. Belostotski, V. Bryzgalov, Y. Salomatin, W. Augustyniak, A. Tkabladze, F. Garibaldi, C. Baumgarten, Ralf Hertenberger, E. Avetissian, H. C. Chiang, B. D. Fox, Y. Holler, V. A. Korotkov, K. Sinram, L. De Nardo, G. Schnell, M. C. Simani, M. Stancari, M. Contalbrigo, V. Vikhrov, W.H.A. Hesselink, S. Potashov, P. E. Reimer, H. Zohrabian, Martin Raithel, Manuella Vincter, E. C. Aschenauer, V. Shutov, M. Henoch, Jeffrey Brack, H. Tanaka, K. Königsmann, B. Krauss, M. Hoek, V. Baturin, I. Sanjiev, A. Airapetian, Hasko Stenzel, C. Scarlett, V. Gharibyan, G. Graw, M. Ehrenfried, Naomi C R Makins, D. Gaskell, R. De Leo, P. Liebing, K. Hafidi, G. Elbakian, A. Borissov, L. Rubacek, M. Vogt, B. Tchuiko, M. Kopytin, J. Lu, A. Nass, B. Hommez, S. Yen, A. Elalaoui-Moulay, Frank Ellinghaus, E. R. Kinney, G. V. Ybeles Smit, R. Seidl, E. Garutti, A. Hillenbrand, V. Mexner, A. Schwind, Ralf Kaiser, Y. Naryshkin, B. Marianski, Andrey V. Izotov, E. De Sanctis, M. Bouwhuis, H. Ohsuga, H. Böttcher, E. Steffens, J. Stewart, A. Brüll, G. Gavrilov, D. Hasch, Y. Miyachi, J. Wendland, K. Oganessyan, A. Laziev, W.-D. Nowak, Michael Tytgat, A. Ivanilov, L. Felawka, V. Gapienko, B. Maiheu, P. Tait, D. H. Potterveld, M. Amarian, C. A. Miller, K. Garrow, J. Ely, A. Rostomyan, A. Avetissian, A. Kisselev, L. Lagamba, A. Fantoni, A. Reischl, S. Taroian, N. Bianchi, A. Nagaitsev, J. J. M. Steijger, Michael Düren, P. Di Nezza, G. Iarygin, Michel Vetterli, G. Ciullo, Christian Schill, H. Marukyan, J. Franz, B. Zihlmann, R. Shanidze, V. Kozlov, S. Frullani, N. Pickert, N. Akopov, O. Grebeniouk, P. F. Dalpiaz, G.P. Capitani, H. P. Blok, P. Zupranski, Wolfgang Lorenzon, V. V. Ammosov, J. Volmer, F. Masoli, N. Meyners, G. Rosner, U. Stosslein, Z. Akopov, G. van der Steenhoven, T. Lindemann, L. G. Greeniaus, C. Weiskopf, A. Borysenko, Klaus Rith, D. Heesbeen, I.A. Savin, Andreas Schäfer, P. Lenisa, A. Trzcinski, D. Reggiani, V. Muccifora, M. Hartig, M. Negodaev, P. Bailey, I. M. Gregor, A. Jgoun, C. Riedl, M. Beckmann, and A. Andrus
Subjects: HERMES experiment, Quark, Nuclear and High Energy Physics, Meson, Nuclear Theory, Hadron, chemistry.chemical_element, 13.87.Fh, 13.60.-r, 14.20.-c, 14.40.-n, 01 natural sciences, 7. Clean energy, Nuclear physics, 0103 physical sciences, Multiplicity (chemistry), Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Krypton, Baryon, Deuterium, chemistry, High Energy Physics::Experiment, Atomic physics
Abstract: The influence of the nuclear medium on lepto-production of hadrons was studied in the HERMES experiment at DESY in semi-inclusive deep-inelastic scattering of 27.6 GeV positrons off deuterium, nitrogen and krypton targets. The differential multiplicity for krypton relative to that of deuterium has been measured for the first time for various identified hadrons (π+, π−, π0, K+, K−, p and p ) as a function of the virtual photon energy ν, the fraction z of this energy transferred to the hadron, and the hadron transverse momentum squared pt2. The multiplicity ratio is strongly reduced in the nuclear medium at low ν and high z, with significant differences among the various hadrons. The distribution of the hadron transverse momentum is broadened towards high pt2 in the nuclear medium, in a manner resembling the Cronin effect previously observed in collisions of heavy ions and protons with nuclei.
Published: 2003

50. Q2 dependence of nuclear transparency for exclusive rho0 production

Author: A, Airapetian, N, Akopov, Z, Akopov, M, Amarian, V V, Ammosov, A, Andrus, E C, Aschenauer, W, Augustyniak, R, Avakian, A, Avetissian, E, Avetissian, P, Bailey, V, Baturin, C, Baumgarten, M, Beckmann, S, Belostotski, S, Bernreuther, N, Bianchi, H P, Blok, H, Böttcher, A, Borissov, M, Bouwhuis, J, Brack, A, Brüll, I, Brunn, G P, Capitani, H C, Chiang, G, Ciullo, M, Contalbrigo, G R, Court, P F, Dalpiaz, R, De Leo, L, De Nardo, E, De Sanctis, E, Devitsin, P, Di Nezza, M, Düren, M, Ehrenfried, A, Elalaoui-Moulay, G, Elbakian, F, Ellinghaus, U, Elschenbroich, J, Ely, R, Fabbri, A, Fantoni, A, Fechtchenko, L, Felawka, B, Fox, J, Franz, S, Frullani, Y, Gärber, G, Gapienko, V, Gapienko, F, Garibaldi, E, Garutti, D, Gaskell, G, Gavrilov, V, Gharibyan, G, Graw, O, Grebeniouk, L G, Greeniaus, W, Haeberli, K, Hafidi, M, Hartig, D, Hasch, D, Heesbeen, M, Henoch, R, Hertenberger, W H A, Hesselink, A, Hillenbrand, Y, Holler, B, Hommez, G, Iarygin, A, Izotov, H E, Jackson, A, Jgoun, R, Kaiser, E, Kinney, A, Kisselev, K, Königsmann, H, Kolster, M, Kopytin, V, Korotkov, V, Kozlov, B, Krauss, V G, Krivokhijine, L, Lagamba, L, Lapikás, A, Laziev, P, Lenisa, P, Liebing, T, Lindemann, W, Lorenzon, N C R, Makins, H, Marukyan, F, Masoli, F, Menden, V, Mexner, N, Meyners, O, Mikloukho, C A, Miller, Y, Miyachi, V, Muccifora, A, Nagaitsev, E, Nappi, Y, Naryshkin, A, Nass, K, Negodaeva, W-D, Nowak, K, Oganessyan, H, Ohsuga, G, Orlandi, S, Podiatchev, S, Potashov, D H, Potterveld, M, Raithel, D, Reggiani, P, Reimer, A, Reischl, A R, Reolon, K, Rith, G, Rosner, A, Rostomyan, D, Ryckbosch, I, Sanjiev, I, Savin, C, Scarlett, A, Schäfer, C, Schill, G, Schnell, K P, Schüler, A, Schwind, J, Seibert, B, Seitz, R, Shanidze, T-A, Shibata, V, Shutov, M C, Simani, K, Sinram, M, Stancari, M, Statera, E, Steffens, J J M, Steijger, J, Stewart, U, Stösslein, H, Tanaka, S, Taroian, B, Tchuiko, A, Terkulov, S, Tessarin, E, Thomas, A, Tkabladze, A, Trzcinski, M, Tytgat, G M, Urciuoli, P, Van Der Nat, G, Van Der Steenhoven, R, Van De Vyver, M C, Vetterli, V, Vikhrov, M G, Vincter, J, Visser, M, Vogt, J, Volmer, C, Weiskopf, J, Wendland, J, Wilbert, T, Wise, S, Yen, S, Yoneyama, B, Zihlmann, H, Zohrabian, and P, Zupranski
Abstract: Exclusive coherent and incoherent electroproduction of the rho(0) meson from 1H and 14N targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q2). The ratio of 14N to 1H cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q2 is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency.
Published: 2002

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