Abstract :
New double-spin asymmetry data from the COMPASS experiment at CERN are presented. The data are used to determine the polarized gluon distribution ΔG/G(x), via three different techniques. Next-to-leading order QCD fits to the nucleon polarized structure functions indicate that the first moment of ΔG/G(x) is small (either positive or negative) and compatible with zero. This observation is corroborated by three measurements of ΔG/G(x), based on the photon-gluon fusion process.
