Time Reversal and Reciprocity in Direct Reactions

Direct-reaction reciprocity tests of time-reversal invariance are analyzed on general grounds and specifically with the T-violating force derived in the preceding paper. A simple proof of Robson's theorem that a cut-off distorted wave Born approximation satisfies reciprocity irrespective of $T$ violation is indicated. Numerical calculations are described which show that Robson's theorem is not a severe restriction on direct-reaction reciprocity tests, and that the violation of reciprocity is of the same order of magnitude as the ratio of the $T$-odd to $T$-normal forces. If the $T$-violating term of the nucleon current contains an isovector part, the $T$-odd potential derived in the preceding paper implies roughly 0.2% violation of reciprocity in deuteron stripping. However, if the basic $T$ violation is isoscalar, the violation of reciprocity will be reduced by a factor of 50 in the context of the model considered.