Configuration assignments and decay of ~(126)La high-spin bands

摘要

High spin states of ~(126)La have been populated using the reaction ~(116)Sn + ~(14)N at 68 MeV. γ-rays and conversion electrons were detected with the GAREL array. Multipolarities of the lowest-lying in-band dipole transitions have been determined from the deduced internal conversion coefficients. Experimental B(M1)/B(E2) ratios have been derived for the bands and compared with calculated values using the Donau-Frauendorf geometrical model. Configurations are proposed for the bands comparing them with cranked shell model calculations and on the basis of the measured B(M1)/B(E2) ratios. The β-decay of ~(126)La has also been revisited. The population of the ~(126)Ba levels gives a probable spin value of five for the decaying high-spin ~(126)La state with T_(1/2)≈64 s which may indicate a signature inversion in the πh_(11/2)νh_(11/2) band.