Details of Eric's veto counter analysis can be found on the Primex wiki
for the
April 20, 2007 analysis meeting. In brief, Eric analyzed pi0 production data
with and without the veto cut, and found that the analysis supports a veto
cut with resulting pi0 yield correction factor that is independent of
pi0 angle.
This correction factor, less than 1% and almost negligible in our
analysis's,
has a slight dependence on including the lead-glass, or not.
Rory