Crossing of shears bands in Pb-197: B(M1) values and semiclassical description - art. no. 132503

Subpicosccond lifetimes of states in shears band 1 in Pb-197 were measured by means of the recoil distance method employing Gammasphere and the New Ya le Plunger Device. The extracted reduced matrix elements, B(M1), show a cle ar sensitivity to the crossing of different shears configurations reflectin g the closing and reopening of the shears blades. The energies and B(Ml) va lues in the band crossing region are successfully described in the framewor k of the semiclassical model of the shears bands. The relevance of core rot ation contributions are shown. The results point to the existence of shears states with an angular momentum coupling angle larger than 90 degrees.