The longitudinal target-spin asymmetry A(UL) for the exclusive electroproduction of high-energy photons was measured for the first time in ep -> e(')p gamma. The data have been accumulated at JLab with the CLAS spectrometer using 5.7 GeV electrons and a longitudinally polarized NH3 target. A significant azimuthal angular dependence was observed, resulting from the interference of the deeply virtual Compton scattering and Bethe-Heitler processes. The amplitude of the sin phi moment is 0.252 +/- 0.042(stat)+/- 0.020(sys). Theoretical calculations are in good agreement with the magnitude and the kinematic dependence of the target-spin asymmetry, which is sensitive to the generalized parton distributions (H) over tilde and H.
MEASUREMENT OF DEEPLY VIRTUAL COMPTON SCATTERING WITH A POLARIZED PROTON TARGET
CORVISIERO, PIETRO;RICCO, GIOVANNI;TAIUTI, MAURO GINO;
2006-01-01
Abstract
The longitudinal target-spin asymmetry A(UL) for the exclusive electroproduction of high-energy photons was measured for the first time in ep -> e(')p gamma. The data have been accumulated at JLab with the CLAS spectrometer using 5.7 GeV electrons and a longitudinally polarized NH3 target. A significant azimuthal angular dependence was observed, resulting from the interference of the deeply virtual Compton scattering and Bethe-Heitler processes. The amplitude of the sin phi moment is 0.252 +/- 0.042(stat)+/- 0.020(sys). Theoretical calculations are in good agreement with the magnitude and the kinematic dependence of the target-spin asymmetry, which is sensitive to the generalized parton distributions (H) over tilde and H.
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