Ja n 20 05 1 ∆ G from high p T events at SMC and high p T analysis at COMPASS

1 ∆G from high p T events at SMC and high p T analysis at COMPASS Measurements of the longitudinal spin cross section asymmetry for deep inelastic muon-nucleon interactions with two high transverse momentum hadrons (p T > 0.7 GeV) in the final state are presented for SMC data for polarized proton and deuteron and for data on polarized deuteron from COMPASS taken in 2002 and 2003. The muon asymmetries determined with a cut on Q 2 > 1 GeV 2 in SMC are: A p = 0.03 ± 0.057 ± 0.01 and A d = 0.070 ± 0.076 ± 0.010, respectively. From these values a gluon polarization ∆G/G = −0.20 ± 0.28 ± 0.10 was obtained at an average fraction of nucleon momentum carried by gluons η = 0.07. The measured asymmetry (with cut on Q 2 > 1 GeV 2) in COMPASS is (A d /D) = −0.015±0.08±0.013 where D is depolarization factor and the gluon polarization