Collins and Sivers asymmetries on the deuteron from COMPASS

Abstract

The COMPASS Experiment at the CERN SPS has a broad physics program focused on the nucleon spin structure and on hadron spectroscopy, using muon and hadron beams. One of the main objectives for the spin program with the muon beam is the measurement of the transversity distribution ΔTq(x) in semi inclusive deep inelastic scattering (SIDIS). In the years 2002, 2003, and 2004 data were collected using a 160 GeV polarized muon beam and a 6LiD target transversely polarized with respect to the muon beam for about 20% of the running time. Here the results for the Collins and the Sivers asymmetries extracted from the 2002 data are presented together with the projected statistical error for the whole 2002–2004 period and for the proton run foreseen in 2006. Results for Λ polarization from 2002–2003 data are also presented.