Longitudinal double spin asymmetries in single hadron quasi-real photoproduction at high pT

We measured the longitudinal double spin asymmetries ALLALL for single hadron muoproduction off protons and deuterons at photon virtuality Q2<1(GeV/c)2 for transverse hadron momenta pTpT in the range 1 GeV/c1 GeV/c to 4 GeV/c4 GeV/c. They were determined using COMPASS data taken with a polarised muon beam of 160 GeV/c160 GeV/c or 200 GeV/c200 GeV/c impinging on polarised 6LiD or NH3 targets. The experimental asymmetries are compared to next-to-leading order pQCD calculations, and are sensitive to the gluon polarisation ΔG   inside the nucleon in the range of the nucleon momentum fraction carried by gluons 0.05