Triaxial nuclear shapes in126I

Abstract

The energy levels of the odd-odd nucleus ${}^{126}$I have been investigated by in-beam $\ensuremath{\gamma}$-ray spectroscopic techniques. Twenty seven new $\ensuremath{\gamma}$ transitions have been identified. The polarization analysis was carried out using the clover detector as a Compton polarimeter. We have made definite parity assignments to six bands. Five of them were in agreement with the previous assignments of parity, but one band for which the theoretical interpretation was earlier reported with an assumed negative parity [Zheng et al., Phys. Rev. C 86, 014320 (2012)] was found to be of positive parity. We have carried out the theoretical analysis of different bands using the particle rotor model and the calculations of the total Routhian surface. The signature inversion observed in the yrast negative-parity band has been understood as the change in the axis of rotation from the shortest to the intermediate axis of the triaxial nucleus. Two positive-parity bands based on the particle configuration $\ensuremath{\pi}{h}_{11/2}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2}$, have been found to be good candidates for the chiral partner behavior.