ENHANCED AND QUENCHED B(E1) TRANSITION RATES BETWEEN PARITY DOUBLET BANDS IN RA-227

The fast timing beta gamma gamma(t) method has been used to measure le vel lifetimes in the parity doublet bands in Ra-227 populated in the b eta(-) decay of Fr-227. In particular, T-1/2 = 254(9) ps, 236(30) ps, less than or equal to 41 ps and 16(13) ps have been measured for the 3 /2(-) and 5/2(-) members of the K-pi = 3/2(-) band and for the 1/2(-) and 3/2(-) members of the K-pi = 1/2(-) band, respectively. These resu lts indicate surprisingly fast B(E1) rates in this octupole transition al nucleus with the average \D-0\ value of greater than or equal to 0. 11 e . fm for the K-pi = 1/2(-) band and \D-0\ = 0.10 e . fm for K-pi = 3/2(-) band. The general enhancement (and occasional quenching) of E 1 intra-doublet and some enhanced extra-doublet transitions in Ra-227 are interpreted within the quasiparticle-plus-phonon model with the in clusion of Coriolis coupling. Similar calculations, performed for Ra-2 23, are found to be in good agreement with the experimental data.