The gluon polarization $\Delta G/G$ at COMPASS

Abstract

The COMPASS experiment will determine the gluon polarization in the nucleon $\Delta G/G$ from the double helicity asymmetry measured in the scattering of a 160 GeV muon beam on a longitudinally polarized deuteron target, by selecting the photon-gluon fusion reaction. This reaction can be tagged either by the production of open charm, or by the production of high $p_T$ hadron pairs. The first asymmetry obtained with the latter method is presented.Comment: 4 pages, 7 figure