The COMPASS experiment at CERN

COMPASS (COmmon Muon and Proton Apparatus for Structure and Spectroscopy) is a fixed target experiment at CERN dedicated to studies of the spin structure of the nucleon and of the spectroscopy of hadrons. During the years 2002-2004, 2006-2007 and 2010-2011 the COMPASS collaboration has collected a large amount of data by scattering polarized 160(200) GeV/c muons on polarized 6LiD and NH3 targets. The COMPASS results on quark and gluon helicities are discussed, as well as results on transverse spin and transverse momentum effects in semi-inclusive deeply inelastic scattering. During 2008 and 2009, the world leading data sets diffractive and centrally produced events were collected with 190 GeV/c hadron beams which are currently being analyzed using Partial Wave Analysis (PWA) technique.