In 1996 and 1997 tests were performed with the pibeta experimental apparatus
using various tunes of the beam at PSI. Data were taken using an array of 44
CsI crystals, 8 half-sized plastic veto staves, the active target and degrader
and a few beam-line detectors. The setup comprised the equivalent of one
supercluster (described in section 3.4.1.1). These data were taken in with the
intent of measuring the p -> e n ( g ) branching ratio.
Additionally, in 1997, a liquid hydrogen target and an array of NaI detectors
were added to make a precise measurement of the Panofsky ratio
[ s ( p - + p -> p 0 + n) /
( s ( p - + p -> g + n)] while
simultaneously measuring the response of the CsI crystals to the 70 MeV
's
produced by the p 0 decay. The analysis described here focuses on
extracting from the 1997 pion decay data the branching ratio
.