Hadron Spectroscopy with COMPASS at CERN

The aim of the COMPASS hadron programme is to study the light-quark hadron spectrum, and in particular, to search for evidence of hybrids and glueballs. COMPASS is a fixed-target experiment at the CERN SPS that features a two-stage spectrometer with high momentum resolution and wide acceptance. It also provides particle identification and calorimetry. A short pilot run in 2004 resulted in the observation of a spin-exotic state with JPC = 1−+ consistent with the debated π1(1600) resonance. In addition, Coulomb production data at low momentum transfer provide a test of Chiral Perturbation Theory. During 2008 and 2009, a world leading data set was collected with hadron beam which is currently being analysed. The unprecedentedly large number of events allows for a thorough decomposition of the data into spin states. The COMPASS hadron data span over a broad range of channels and shed light on several different aspects of QCD.