Signature splitting in128La and130La

Abstract

Band structures have been studied in the odd-odd nuclei 128,130La using gamma-ray spectroscopy techniques and heavy-ion-induced reactions. The states in 130La are reported for the first time. Signature splitting is seen in 128La both in transition energies and in B(M1)/B(E2) ratios, but not in 130La. The states are suggested to arise from a pi h11/2(X) upsilon h11/2 configuration, the signature splitting in 128La being evidence for a triaxial shape.