Orateur
Dr
Frank Nerling
(University of Freiburg)
Description
The COMPASS experiment at CERN SPS is dedicated to the study of hadron structure and spectroscopy. One goal of the physics programme using hadron beams is the search for new states, in particular the search for J^{PC} spin-exotic states and glueballs. Apart from a short pilot run in 2004 (190 GeV/c negative pion beam, lead target), we started our hadron spectroscopy programme in 2008 by collecting unprecedented statistics with a negative hadron beam (190 GeV/c) on a liquid hydrogen target. A similar amount of data with positive hadron beam (190 GeV/c) has been taken in 2009, as well as some data (negative beam) on nuclear targets.
Our spectrometer features good coverage by electromagnetic calorimetry, crucial for the detection of final states involving $\pi^0$ or $\eta. For scattering of negatively charged pions off nuclear targets, photon exchange dominates at very low momentum transfer, giving access to $\pi^-\gamma$ induced reactions (Primakoff). By detection of exclusive $\pi^-\gamma$ final states, COMPASS further aims at the precise measurement of the pion polarisability. Studying also the exclusive $\pi^-\pi^0$ final state, allows a precise determination of the chiral anomaly. We will present an selective overview of the status of various ongoing
analyses and first results on the 2008/09 data.
Auteur principal
Dr
Frank Nerling
(University of Freiburg)
