Lifetimes of excited states in octupole-collective<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Ba</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>142</mml:mn><mml:mo>,</mml:mo><mml:mn>144</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>nuclei
Annotatsiya
Lifetimes of excited states have been measured for the positive-parity rotational bands in neutron-rich $^{142,144}\mathrm{Ba}$ as well as the ${7}^{\ensuremath{-}}$ and ${9}^{\ensuremath{-}}$ states of the negative-parity band in $^{144}\mathrm{Ba}$ 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 ${7}^{\ensuremath{-}}$ and ${9}^{\ensuremath{-}}$ 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 $^{144}\mathrm{Ba}$.