Signature splitting inversion and backbending in 80Rb

TL;DR

This study explores high spin states and signature phenomena in 80Rb through experimental gamma-ray spectroscopy, revealing new states, band crossings, and signature inversions, and compares findings with theoretical models and isotone structures.

Contribution

It provides the first observation of multiple band crossings and signature inversions in 80Rb, expanding understanding of nuclear structure at high spins.

Findings

23 new states and 28 new gamma transitions identified.

First observation of multiple band crossings in 80Rb.

Signature inversion analyzed using the projected shell model.

Abstract

High spin states of 80Rb are studied via the fusion-evaporation reactions 65Cu+19F, 66Zn+18O and 68Zn+16O with the beam energies of 75 MeV, 76 MeV and 80 MeV, respectively. Twenty-three new states with twenty-eight new \gamma transitions were added to the previously proposed level scheme, where the second negative-parity band is significantly pushed up to spins of 22^{-} and 15^{-} and two new sidebands are built on the known first negative-parity band. Two successive band crossings with frequencies 0.51 MeV and 0.61 MeV in the \alpha=0 branch as well as another one in the \alpha=1 branch of the second negative-parity band are observed for the first time. Signature inversions occur in the positive- and first negative-parity bands at the spins of 11\hbar and 15\hbar, respectively. The signature splitting is seen obviously in the second negative-parity band, but the signature inversion is not observed. It is also found that the structure of the two negative-parity bands is similar to that of its isotone ^{82}Y. Signature inversion in the positive-parity yrast band with configuration \pi g_{9/2} \otimes \nu g_{9/2} in this nucleus is discussed using the projected shell model (PSM).