Shape coexistence and isospin symmetry in $A=70$ nuclei: Spectroscopy of the $T_z = -1$ nucleus $^{70}$Kr

TL;DR

This study investigates the excited states of the $^{70}$Kr nucleus, revealing shape coexistence and isospin symmetry through spectroscopy and gamma-ray analysis, contributing to understanding nuclear structure in this mass region.

Contribution

It provides the first detailed level scheme of $^{70}$Kr and evidence for shape coexistence, comparing experimental data with mirror nucleus $^{70}$Se.

Findings

Identification of multiple gamma-ray transitions in $^{70}$Kr.

Observation of a second $2^+$ state indicating shape coexistence.

Comparison with mirror nucleus $^{70}$Se$ suggests isospin symmetry.

Abstract

Excited states in the $T_z=-1$ nucleus $^{70}$Kr have been populated using inelastic scattering of a radioactive $^{70}$Kr beam as well as one- and two-neutron removal reactions from $^{71,72}$Kr at intermediate beam energies. The level scheme of $^{70}$Kr was constructed from the observed $\gamma$-ray transitions and coincidences. Tentative spin and parity assignments were made based on comparison with the mirror nucleus $^{70}$Se. A second $2^+$ state and a candidate for the corresponding $4^+_2$ state suggest shape coexistence in $^{70}$Kr.