Double spin asymmetry in photoproduction of High-PT hadron pairs Original Research Article

Experimental results from HERMES are presented on longitudinal spin asymmetry in photoproduction of pairs of oppositely charged hadrons with high transfers kimenta PT. Monte Carlo studies with the PYTHIA [1] event generator suggest that in the kinematical domain of the measurement, photon-gluon fusion (PGF) dominates over other underlying background subprocesses. Using this model, the measured asymmetry is interpreted in terms of a positive gluon polarization in the nucleon.