Shape effects in h112 and g72 bands in Tm159

The 72[523] and 72[404] bands are observed in Tm159 to I=612 and 432, respectively, well beyond the i132 neutron backbend. Before the backbend, the 72[523] band exhibits large signature splitting, the 72[404] none, which is interpreted as resulting from the very different driving influences of the K=72, h112, and g72 orbits, respectively, on the core triaxiality. The i132 neutron alignment changes the signaure splitting in each band as a result of its dominant driving force to positive values of γ. Measured B(M1;I→I-1)B(E2;I→I-2) values increase dramatically after the backbend, and this is explained in terms of calculated increases in the M1 transition rates and decreases in the E2 rates.