Exclusive Leptoproduction of Real Photons on a Longitudinally Polarised Hydrogen Target

Collaboration
Apr, 2010
19 pages
Published in:
  • JHEP 06 (2010) 019
e-Print:
Report number:
  • DESY-10-046
Experiments:

Citations per year

20102014201820222025051015
Abstract: (arXiv)
Polarisation asymmetries are measured for the hard exclusive leptoproduction of real photons from a longitudinally polarised hydrogen target. These asymmetries arise from the deeply virtual Compton scattering and Bethe-Heitler processes. From the data are extracted two asymmetries in the azimuthal distribution of produced real photons about the direction of the exchanged virtual photon: A_UL with respect to the target polarisation and A_LL with respect to the product of the beam and target polarisations. Results for both asymmetries are compared to the predictions from a generalised parton distribution model. The sin(phi) and cos(0*phi) amplitudes observed respectively for the A_UL and A_LL asymmetries are compatible with the sizeable predictions from the model. Unexpectedly, a sin(2*phi) modulation in the A_UL asymmetry with a magnitude similar to that of the sin(phi) modulation is observed.
Note:
  • 18 pages, 2 figures, 5 tables
  • Lepton-Nucleon Scattering
  • positron p: exclusive reaction
  • photon: electroproduction
  • polarized beam: longitudinal
  • polarized target: longitudinal
  • deeply virtual Compton scattering
  • scattering: Bethe-Heitler
  • angular distribution: asymmetry
  • generalized parton distribution
  • HERMES
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