We report the first results of the beam-spin asymmetry measured in the reaction e→p → epγ at a beam energy of 4.25 GeV. A large asymmetry with a sinφ modulation is observed, as predicted for the interference term of deeply virtual compton scattering (DVCS) and the Bethe-Heitler process. The amplitude of this modulation is α=0.202±0.028. In leading-order and leading-twist perturbative QCD, the α is directly proportional to the imaginary part of the DVCS amplitude.
|Number of pages||1|
|Journal||Physical Review Letters|
|State||Published - Jan 1 2001|
ASJC Scopus subject areas
- Physics and Astronomy (all)