Lifetimes of excited states in octupole-collective 142,144Ba nuclei.

Lifetimes of excited states have been measured for the positive-parity rotational bands in neutron-rich Ba-142,Ba-144 as well as the 7(-) and 9(-) states of the negative-parity band in Ba-144 using the differential Doppler shift method. The deduced quadrupole moment, Q(t), of the positive-parity band decreases with angular momentum and overall shows good agreement with earlier measurements. The measured lifetimes of 7(-) and 9(-) states are used to determine the electric dipole moment, D-0=0.17(3) and 0.09(1) e fm, respectively, in the negative-parity octupole band of Ba-144.