Analysis Of Negative-Pion Photoproduction Near P33 Resonance - Test Of Delta I Less Than Or Equal To 1 Rule And Time Reversal In Variance

Angular distribution for the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}\ensuremath{\gamma}n$ 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 $\ensuremath{-}0.1>x>\ensuremath{-}0.4$. 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 $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{E}=1245$ MeV and the inverse reaction deduced from $\ensuremath{\gamma}d$ work. A strong violation in the isovector or isotensor amplitude is excluded, but a maximum violation in the isoscalar amplitude is possible.