Angular distribution of ${\hat{I}}^3$-rays from a neutron-induced $p$-wave resonance of ${}^{132}$Xe

Abstract

A neutron-energy dependent angular distribution was measured for individual ${\hat{I}}^3$-rays from the 3.2 eV $p$-wave resonance of ${}^{131}$Xe+$n$, that shows enhanced parity violation owing to a mixing between $s$- and $p$-wave amplitudes. The ${\hat{I}}^3$-ray transitions from the $p$-wave resonance were identified, and the angular distribution with respect to the neutron momentum was evaluated as a function of the neutron energy for 7132 keV ${\hat{I}}^3$-rays, which correspond to a transition to the 1807 keV excited state of ${}^{132}$Xe. The angular distribution is considered to originate from the interference between $s$- and $p$-wave amplitudes, and will provide a basis for a quantitative understanding of the enhancement mechanism of the fundamental parity violation in compound nuclei.