First lifetime measurement of the \(9^{-}\) isomer in \(^{92}\)Nb

Abstract

A new \(9^-\) isomer has been identified in odd-odd nuclide, \(^{92}\)Nb which was populated using the reaction \(^{80}\)Se(\(^{18}\)O, p5n)\(^{92}\)Nb at a beam energy of 99 MeV. The \(\gamma -\gamma \) coincidences were measured using Indian National Gamma Array (INGA). The previously reported isomeric state at \(11^-\) was revisited and the half-life is measured to be 103.6(32) ns. The half-life of the newly observed 9\(^- \) isomer in \(^{92}\)Nb has been measured to be 35.8(23) ns for the first time. The transition probability \(\textit{B}(\textit{E}\)2) has been determined for the isomeric state. The isomeric structure has been interpreted as a four-quasiparticle excitation, consisting of three protons and one neutron, using large-scale shell model calculations.