Partner bands of 126Cs – first observation of chiral electromagnetic selection rules

Abstract

The lifetimes of the excited states belonging to the chiral partner bands built on the πh11/2⊗νh11/2−1 configuration in 126Cs have been measured using the DSA technique. For the first time the large set of the experimental transition probabilities is in qualitative agreement with all selection rules predicted for the strong chiral symmetry breaking limit. The selection rules originate from two general features of a chiral nucleus, namely, from the existence of well separated left- and right-handed systems built of three angular momentum vectors and extra symmetries appearing in addition to the chiral symmetry breaking. The B(M1) staggering resulting from these additional symmetries is sensitive to triaxiality of odd–odd nuclei as well as configuration of valence particles.