Analysis of Negative-Pion Photoproduction Near the P33 Resonance: Test of the ∆I<=1 Rule and Time-Reversal Invariance
Angular distribution for the reaction π-p-->γn are analyzed. Existing sets of multipoles do not agree with the data. An acceptable fit is obtained with the Sanda-Shaw model of an electromagnetic current with an isotensor component of -0.1>x>-0.4. The model of Christ and Lee is used to estimate the magnitude of a possible T-invariance violation implied by the difference between the data at E~=1245 MeV and the inverse reaction deduced from γd work. A strong violation in the isovector or isotensor amplitude is excluded, but a maximum violation in the isoscalar amplitude is possible.