The first candidate for chiral nuclei in the $A\sim 80$ mass region: ${}^{80}$Br

Abstract

Excited states of ${}^{80}$Br have been investigated via the ${}^{76}$Ge(${}^{11}$B, $\hat{I}\pm$3n) and ${}^{76}$Ge(${}^7$Li, 3n) reactions and a new $\hat{I}”I$ = 1 band has been identified which resides $\sim$ 400 keV above the yrast band. Based on the experimental results and their comparison with the triaxial particle rotor model calculated ones, a chiral character of the two bands within the $\ddot{I}€g_{9/2}\otimes \hat{I}½g_{9/2}$ configuration is proposed, which provides the first evidence for chirality in the $A\sim 80$ region.

15 pages, 6 figures, accepted for publication in Physics Letters B