Investigation of lifetimes in the dipole band of 139 Sm

Lifetimes have been measured for a dipole band in 139 Sm using DSAM. The deduced B ( M 1) and B ( E 2) values as well as B ( M 1)/ B ( E 2) ratios are compared with calculations in the framework of the TAC (Tilted Axis Cranking) and SPAC (Shears mechanism with Principal Axis Cranking) models. The dipole band in 139 Sm can be considered as a magnetic rotational band with a prolate or triaxial nuclear deformation.