Enhanced Quadrupole and Octupole Strength in Doubly Magic ^{132}Sn.

D Rosiak,P Reiter,L Kaya,A Vogt,A Blazhev,A Illana,M Seidlitz,F Nowacki,Y Tsunoda,G Colò,H Naïdja,J Ojala,M Queiser,K Arnswald,J Pakarinen,G Rainovski,J Snäll,T Berry,H De Witte,C Henrich,M Von Schmid,N Warr,R Hirsch,K Johnston,J Cederkäll,B Siebeck,E Siesling,F Wenander,Thilo Kroll ,M Huýse ,Miguel Lozano Benito ,José A Rodríguez ,M J G Borge ,L P Gaffney ,D M Cox ,Tomoaki Togashi ,Piet Van Duppen ,Takaharu Otsuka ,K O Zell

doi:10.1103/physrevlett.121.252501

Abstract

The first 2^{+} and 3^{-} states of the doubly magic nucleus ^{132}Sn are populated via safe Coulomb excitation employing the recently commissioned HIE-ISOLDE accelerator at CERN in conjunction with the highly efficient MINIBALL array. The ^{132}Sn ions are accelerated to an energy of 5.49 MeV/nucleon and impinged on a ^{206}Pb target. Deexciting γ rays from the low-lying excited states of the target and the projectile are recorded in coincidence with scattered particles. The reduced transition strengths are determined for the transitions 0_{g.s.}^{+}→2_{1}^{+}, 0_{g.s.}^{+}→3_{1}^{-}, and 2_{1}^{+}→3_{1}^{-} in ^{132}Sn. The results on these states provide crucial information on cross-shell configurations which are determined within large-scale shell-model and MonteCarlo shell-model calculations as well as from random-phase approximation and relativistic random-phase approximation. The locally enhanced B(E2;0_{g.s.}^{+}→2_{1}^{+}) strength is consistent with the microscopic description of the structure of the respective states within all theoretical approaches. The presented results of experiment and theory can be considered to be the first direct verification of the sphericity and double magicity of ^{132}Sn.

Highlights

The first 2þ and 3− states of the doubly magic nucleus 132Sn are populated via safe Coulomb excitation employing the recently commissioned HIE-ISOLDE accelerator at CERN in conjunction with the highly efficient MINIBALL array
The reduced transition strengths are determined for the transitions 0þg:s: → 2þ1, 0þg:s: → 3−1, and 2þ1 → 3−1 in 132Sn. The results on these states provide crucial information on cross-shell configurations which are determined within large-scale shellmodel and Monte Carlo shell-model calculations as well as from random-phase approximation and relativistic random-phase approximation
The locally enhanced BðE2; 0þg:s: → 2þ1 Þ strength is consistent with the microscopic description of the structure of the respective states within all theoretical approaches

Summary

Introduction

The first 2þ and 3− states of the doubly magic nucleus 132Sn are populated via safe Coulomb excitation employing the recently commissioned HIE-ISOLDE accelerator at CERN in conjunction with the highly efficient MINIBALL array. While nuclei around Z 1⁄4 50, N 1⁄4 82 could be treated within the SM, predictions for doubly magic 132Sn, its excited 2þ1 and 3−1 states, and the respective electromagnetic properties were not accessible until now due to the huge valence space and computational complexity including several shells for protons and neutrons simultaneously. The present Letter reports the results for the 2þ1 and 3−1 states in 132Sn and their transition strengths obtained in a Coulombexcitation (CE) experiment performed at the newly commissioned HIE-ISOLDE facility at CERN [19,20].

Results

Conclusion