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Title: Evidence for a Single-Spin Azimuthal Asymmetry in Semi-inclusive Pion Electroproduction

Abstract

Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle {phi} of the pion relative to the lepton scattering plane was formed for {pi}{sup +} electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sin {phi} moment of the cross section is 0.022{+-}0.005{+-}0.003 . This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark. (c) 2000 The American Physical Society.

Authors:
 [1];  [1];  [2];  [3];  [4];  [5];  [6];  [6];  [7];  [1];  [1];  [7];  [8];  [9]
  1. Yerevan Physics Institute, 375036, Yerevan, (Armenia)
  2. Nationaal Instituut voor Kernfysica en Hoge-Energiefysica (NIKHEF), 1009 DB Amsterdam, The Netherlands (Netherlands)
  3. (Italy)
  4. (Armenia)
  5. Department of Subatomic and Radiation Physics, University of Gent, 9000 Gent, (Belgium)
  6. (Germany)
  7. Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, 00044 Frascati, (Italy)
  8. Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States)
  9. Sektion Physik, Universitaet Muenchen, 85748 Garching, (Germany) (and others)
Publication Date:
OSTI Identifier:
20216330
Resource Type:
Journal Article
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 84; Journal Issue: 18; Other Information: PBD: 1 May 2000; Journal ID: ISSN 0031-9007
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DEEP INELASTIC SCATTERING; ELECTROPRODUCTION; ELECTRON-PROTON INTERACTIONS; PIONS PLUS; POLARIZED TARGETS; CROSS SECTIONS; SPIN; EXPERIMENTAL DATA

Citation Formats

Airapetian, A., Akopov, N., Amarian, M., Istituto Nazionale di Fisica Nucleare, Sezione Sanita and Physics Laboratory, Istituto Superiore di Sanita, 00161 Roma,, Yerevan Physics Institute, 375036, Yerevan,, Aschenauer, E. C., Max-Planck-Institut fuer Kernphysik, 69029 Heidelberg,, DESY Zeuthen, 15738 Zeuthen,, Avakian, H., Avakian, R., Avetissian, A., Avetissian, E., Bains, B., and Baumgarten, C. Evidence for a Single-Spin Azimuthal Asymmetry in Semi-inclusive Pion Electroproduction. United States: N. p., 2000. Web. doi:10.1103/PhysRevLett.84.4047.
Airapetian, A., Akopov, N., Amarian, M., Istituto Nazionale di Fisica Nucleare, Sezione Sanita and Physics Laboratory, Istituto Superiore di Sanita, 00161 Roma,, Yerevan Physics Institute, 375036, Yerevan,, Aschenauer, E. C., Max-Planck-Institut fuer Kernphysik, 69029 Heidelberg,, DESY Zeuthen, 15738 Zeuthen,, Avakian, H., Avakian, R., Avetissian, A., Avetissian, E., Bains, B., & Baumgarten, C. Evidence for a Single-Spin Azimuthal Asymmetry in Semi-inclusive Pion Electroproduction. United States. doi:10.1103/PhysRevLett.84.4047.
Airapetian, A., Akopov, N., Amarian, M., Istituto Nazionale di Fisica Nucleare, Sezione Sanita and Physics Laboratory, Istituto Superiore di Sanita, 00161 Roma,, Yerevan Physics Institute, 375036, Yerevan,, Aschenauer, E. C., Max-Planck-Institut fuer Kernphysik, 69029 Heidelberg,, DESY Zeuthen, 15738 Zeuthen,, Avakian, H., Avakian, R., Avetissian, A., Avetissian, E., Bains, B., and Baumgarten, C. Mon . "Evidence for a Single-Spin Azimuthal Asymmetry in Semi-inclusive Pion Electroproduction". United States. doi:10.1103/PhysRevLett.84.4047.
@article{osti_20216330,
title = {Evidence for a Single-Spin Azimuthal Asymmetry in Semi-inclusive Pion Electroproduction},
author = {Airapetian, A. and Akopov, N. and Amarian, M. and Istituto Nazionale di Fisica Nucleare, Sezione Sanita and Physics Laboratory, Istituto Superiore di Sanita, 00161 Roma, and Yerevan Physics Institute, 375036, Yerevan, and Aschenauer, E. C. and Max-Planck-Institut fuer Kernphysik, 69029 Heidelberg, and DESY Zeuthen, 15738 Zeuthen, and Avakian, H. and Avakian, R. and Avetissian, A. and Avetissian, E. and Bains, B. and Baumgarten, C.},
abstractNote = {Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle {phi} of the pion relative to the lepton scattering plane was formed for {pi}{sup +} electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sin {phi} moment of the cross section is 0.022{+-}0.005{+-}0.003 . This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark. (c) 2000 The American Physical Society.},
doi = {10.1103/PhysRevLett.84.4047},
journal = {Physical Review Letters},
issn = {0031-9007},
number = 18,
volume = 84,
place = {United States},
year = {2000},
month = {5}
}