COMPASS experiment at CERN: open charm results and future hadron program

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 and 2006–2007, the COMPASS collaboration has collected a large amount of data by scattering polarized 160 GeV/c muons on polarized 6LiD and NH3 targets. These data were used to evaluate the gluon contribution to the nucleon spin. The gluon polarization was directly measured from the cross-section helicity asymmetry of D0 mesons production in the photon-gluon fusion reaction. In 2008 COMPASS will perform a search for JPC-exotic mesons, glueballs or hybrids, through light hadron spectroscopy in high energy (190 GeV/c π−) pion-proton reactions using both centrally produced and diffractive events. Preliminary results from diffractive pion dissociation into a π−π−π+ final state obtained in 2004 are also discussed.