Recent Results on Deeply Virtual Compton Scattering at HERMES

HERMES has measured azimuthal asymmetries in the hard electroproduction of real photons, the so-called Deeply Virtual Compton Scattering (DVCS) process, using 27.6 GeV HERA positron and electron beams and various polarized and unpolarized gaseous targets. New results have recently been obtained for the t, x and Q2 dependencies of the transverse target-spin asymmetry (TTSA) from data accumulated in 2002–2004 with the positron beam and a transversely polarized hydrogen target. A model-dependent constraint on the total angular momentum carried by u- and d-quarks, Ju and Jd, is obtained by comparing the extracted TTSA amplitude with theoretical predictions based on a certain GPD model.