Hybrid Meson Structure at COMPASS

We describe a pion physics program attainable with the CERN COMPASSspectrometer, involving tracking detectors and an electromagnetic calorimeter.COMPASS can realize state-of-the-art pion beam hybrid meson and meson radiativetransition studies. We review here the physics motivation for this program. Wedescribe the beam, detector, trigger requirements, and hardware/softwarerequirements for this program. The triggers for all this hybrid meson physicscan be implemented for simultaneous data taking. We will investigate hybrid meson production via pion-photon Primakoff andpion-Pomeron diffractive interactions. We will determine new properties ofquark-antiquark-gluon hybrid mesons, using unique production methods, toimprove our understanding of these exotic mesons. The CERN COMPASS experiment uses 100-280 GeV beams (muon, pion), and magneticspectrometers and calorimeters, to measure the complete kinematics ofpion-photon and pion-Pomeron reactions. The COMPASS experiment is currentlyunder construction, and scheduled to begin data runs in 2001. We carry outsimulation studies to optimize the beam, detector, trigger, andhardware/software for achieving high statistics data with low systematicuncertainties in the hybrid meson component of this program. We will improveprevious Primakoff Hybrid studies by three orders of magnitude. We implementspecial detectors and triggers for hybrid meson production reactions. Wepropose to prepare for these COMPASS pion beam hybrid studies by setting upwith muon beam tests.