Time-Reversal Invariance and Beta-Gamma Angular Correlation. II

The angular-correlation function between beta and gamma rays from oriented nuclei (with or without observation of circular polarization) is given for use in testing the invariance property of the beta interactions under time reversal. The formulas are derived in the cases where the beta decay is an allowed or first forbidden transition and the gamma ray has a mixture of arbitrary multipolarities. A general form for the $\beta -{\gamma }_1-{\gamma }_2$ angular correlation in triple cascade transitions of unoriented nuclei is also shown. It does not give clear-cut information on the invariance property of beta interactions under time reversal. The correlation functions where gamma rays are replaced by alpha particles are discussed in the above two cases. The beta-alpha directional correlation from oriented nuclei may be useful in testing the invariance property of beta interactions under time reversal.