Measurement of the angular distribution of γ-rays emitted from the compound state after neutron capture by 81 Br for a search of T-violation

It is known that parity violation can be enhanced in compound nuclei due to mixing of s- and p-waves, and it is suggested that time reversal invariance (T) violation is enhanced by the same mechanism. We are planing a T-violation search using compound nuclei produced in neutron capture reactions. Although 81 Br is one of the candidate target nuclei, its sensitivity to T-violation has not yet been determined. For an estimate of the latter, a measurement of the angular distribution of γ-rays emitted in the 81 Br(n,γ) reaction was carried out in November 2017, of which we report first results.