Leading order determination of the gluon polarisation from DIS events with high-pT 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 6LiD 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.
Physics Letters B
- Pub Date:
- January 2013
- High Energy Physics - Experiment
- 13 pages, 6 figures and 3 tables