Hybrid Meson Structure at COMPASS
  We describe a pion physics program attainable with the CERN COMPASS spectrometer, involving tracking detectors and an electromagnetic calorimeter. COMPASS can realize state-of-the-art pion beam hybrid meson and meson radiative transition studies. We review here the physics motivation for this program. We describe the beam, detector, trigger requirements, and hardware/software requirements for this program. The triggers for all this hybrid meson physics can be implemented for simultaneous data taking.   We will investigate hybrid meson production via pion-photon Primakoff and pion-Pomeron diffractive interactions. We will determine new properties of quark-antiquark-gluon hybrid mesons, using unique production methods, to improve our understanding of these exotic mesons.   The CERN COMPASS experiment uses 100-280 GeV beams (muon, pion), and magnetic spectrometers and calorimeters, to measure the complete kinematics of pion-photon and pion-Pomeron reactions. The COMPASS experiment is currently under construction, and scheduled to begin data runs in 2001. We carry out simulation studies to optimize the beam, detector, trigger, and hardware/software for achieving high statistics data with low systematic uncertainties in the hybrid meson component of this program. We will improve previous Primakoff Hybrid studies by three orders of magnitude. We implement special detectors and triggers for hybrid meson production reactions. We propose to prepare for these COMPASS pion beam hybrid studies by setting up with muon beam tests. 
Murray Moinester (Tel Aviv U.), Suh Urk Chung (Brookhaven National   Laboratory)