States have been established in the neutron-deficient Gd139 nucleus for the first time via the Mo92(50Cr,2pn) reaction. Both - and -n coincidence techniques were employed. The yrast band, built on the 1/2h11/2(9/2- orbital, shows a signature splitting of 1/4100 keV implying a significant triaxial shape. At a rotational frequency Latin small letter h with stroke1/40.29 MeV a pair of h11/2 quasiprotons align. Associated with this alignment are a decrease in the signature splitting, indicating a near-prolate nuclear shape, and an enhancement of the interband M1 transitions relative to the E2 crossovers, which is consistent with a mixed neutron-proton configuration. In addition, a tentative decoupled band showing the characteristics of a band theoretically expected for the -driving 1/2i13/2 orbital was observed.
ASJC Scopus subject areas
- Nuclear and High Energy Physics