Rotational band structure in 133Pr.

Abstract

The level structure of the odd proton nucleus $^{133}\mathrm{Pr}$ has been investigated. Excited states up to spin frac452 have been observed. The yrast band, built on a decoupled ${h}_{\frac{11}{2}}$ proton, shows an up-bend at $\ensuremath{\hbar}\ensuremath{\omega}=0.43$ MeV when two additional ${h}_{\frac{11}{2}}$ protons align. Two positive parity side bands, based on the ${g}_{\frac{7}{2}}{\frac{5}{2}}^{+}[413]$ proton configuration, are established with opposite signature. Both show a band crossing at $\ensuremath{\hbar}{\ensuremath{\omega}}_{c}=0.27$ MeV with a gain in $\mathrm{alignment}\ensuremath{\approx}8\ensuremath{\hbar}$, when two ${h}_{\frac{11}{2}}$ protons decouple. This low crossing frequency is partly explained by a reduction in the proton pairing gap caused by the ${g}_{\frac{7}{2}}$ proton.