A Measurement of Spin Asymmetries in Quasi-Real Photo-Production of Hadrons with High Transverse Momentum at COMPASS

During 2002–2004, the COMPASS experiment at the CERN SPS has recorded 1.5 fb−1 of deep inelastic scattering events with polarized muon beam and polarized deuterium target. The cross section for singleinclusive charged hadron production in dependence on the hadron's transverse momentum pT is extracted. A PYTHIA and GEANT simulation is used to obtain the acceptance correction factors. The double spin asymmetry $A^{hd}_{LL}$ is measured in the region 1 GeV/c < pT < 3:5 GeV/c, the pT dependence of which is connected to the gluon polarization $\DeltaG$.