Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries

摘要

The beam-spin asymmetries in the hard exclusive electroproduction of photons on the proton (ep → epγ) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering. Over the whole kinematic range (x_B from 0.11 to 0.58, Q~2 from 1 to 4.8 GeV~2, -t from 0.09 to 1.8 GeV~2), the azimuthal dependence of the asymmetries is compatible with expectations from leading-twist dominance, A approx= a sinφ/(1 + c cosφ). This extensive set of data can thus be used to constrain significantly the generalized parton distributions of the nucleon in the valence quark sector.