Observation of exclusive DVCS in polarized electron beam asymmetry measurements
arXiv:hep-ex/0107043 · doi:10.1103/PhysRevLett.87.182002
Abstract
We report the first results of the beam spin asymmetry measured in the reaction e + p -> e + p + gamma at a beam energy of 4.25 GeV. A large asymmetry with a sin(phi) modulation is observed, as predicted for the interference term of Deeply Virtual Compton Scattering and the Bethe-Heitler process. The amplitude of this modulation is alpha = 0.202 +/- 0.028. In leading-order and leading-twist pQCD, the alpha is directly proportional to the imaginary part of the DVCS amplitude.
6 pages, 5 figures