  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.
