Leading order determination of the gluon polarisation from DIS events with high- hadron pairs

We present a determination of the gluon polarisation Δg/g in the nucleon, based on the longitudinal double-spin asymmetry of DIS events with Q2>1 (GeV/c)2 including a pair of large transverse-momentum hadrons in the final state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV/c polarised muon beam scattering off a polarised View the MathML source target. The gluon polarisation is evaluated by a Neural Network approach for three intervals of the gluon momentum fraction xg covering the range 0.04<xg<0.27. The values obtained at leading order in QCD do not show any significant dependence on xg. Their average is Δg/g=0.125±0.060 (stat.)±0.063 (syst.) at average xg=0.09 and a scale of μ2=3 (GeV/c)2.