Transverse target spin asymmetries at COMPASS

COMPASS is a fixed target experiment at the CERN M2 beamline where the nucleon spin structure is investigated using a 160 GeV/c polarized mu(+) beam and polarized solid state targets. After taking data in the years 2002-2004 using a transversely polarized (LiD)-Li-6 (deuteron) target, in 2007 and 2010 additional data were collected on a transversely polarized NH3 (proton) target. The measurements of single spin asymmetries in semi-inclusive deep inelastic scattering (SIDIS) on a transversely polarized target are an important part of the COMPASS physics program. They allow to investigate the transversity distribution functions, e.g. coupled to the Collins fragmentation function, as well as transverse momentum dependent distribution functions, like the Sivers distribution function, by measuring azimuthal asymmetries in hadron production.