The shears mechanism in the lead isotopes

Abstract

Lifetimes of states in at least one of the M1 bands in each nucleus from 193−197Pb have been determined through Doppler-Shift Attenuation Method experiments performed with the Gammasphere array. The nuclei were populated under similar conditions allowing accurate relative measurements of the state lifetimes. The deduced B(M1) values display the characteristic decrease with increasing angular momentum which is a clear signature of the shears mechanism. Combined with the recent results for 198,199Pb an impressive body of evidence now exists which supports the interpretation of these structures as examples of a new mode of nuclear behavior: `magnetic rotation'.