6533b829fe1ef96bd12896f6

RESEARCH PRODUCT

New measurements of at COMPASS

subject

description

One of the main goals of the COMPASS experiment at CERN is the determination of the gluon polarisation in the nucleon, Δ G / G . It is determined from spin asymmetries in the scattering of polarised muons at 160 GeV/c on a polarised LiD target. The gluon polarisation is accessed by the selection of photon-gluon fusion events. Such events are tagged either with a charmed meson or a hadron pair with high transverse momenta in the final state. The selection of charmed mesons is based on the reconstruction of decayed D ⋆ and D 0 mesons in the COMPASS spectrometer. For the high- p T hadron pairs two independent analyses are performed in the kinematic regimes of DIS ( Q 2 > 1 ( GeV / c ) 2 ) and quasi-real photoproduction ( Q 2 1 ( GeV / c ) 2 . The results presented in this paper were obtained from the data coming from 2002–2004 for the open charm and the high p T with Q 2 1 ( GeV / c ) 2 channels resp. from 2002–2003 for the high p T with Q 2 > 1 ( GeV / c ) 2 channel.