Emergence of magnetic dipole band in 88Sr due to novel stretched coupling scheme

Abstract

High spin states of ⁸⁸Sr have been populated using ¹³C + ⁸²Se reaction. The structure of a negative parity band consisting of six magnetic dipole transitions with energies of 605 - 490 - 311 - 267 - 528 - 974 keV extending up to $I^{\pi }$ = ${13}^{-}$ was investigated through lifetimes measurements using Doppler Shift Attenuation Method (dsam). The extracted transition strengths from the measured lifetimes initially increase with spin and then decrease beyond $I^{\pi }$ = ${10}^{-}$. The observed gamma-ray energy behaviour and that of transition rates were explained using a novel stretched coupling scheme. In this geometrical model, an interplay between a particle-particle attractive shears and two particle-hole repulsive shears has been invoked to explain the observed behaviour. This confirms the existence of an attractive shears between two particle blades for the first time in any nuclei.