Shape coexistence revealed in the isotope Kr through inelastic scattering

K. Wimmer; T. Arici; W. Korten; P. Doornenbal; J.-P. Delaroche; M. Girod; J. Libert; T. R. Rodríguez; P. Aguilera; A. Algora; T. Ando; H. Baba; B. Blank; A. Boso; S. Chen; A. Corsi; P. Davies; G. de Angelis; G. de France; D. T. Doherty; J. Gerl; R. Gernhäuser; T. Goigoux; D. Jenkins; G. Kiss; S. Koyama; T. Motobayashi; S. Nagamine; M. Niikura; S. Nishimura; A. Obertelli; D. Lubos; V. H. Phong; B. Rubio; E. Sahin; T. Y. Saito; H. Sakurai; L. Sinclair; D. Steppenbeck; R. Taniuchi; V. Vaquero; R. Wadsworth; J. Wu; M. Zielinska

doi:10.1140/epja/s10050-020-00171-3

2023 Impact factor 2.6

Hadrons and Nuclei

Eur. Phys. J. A (2020) 56: 159
https://doi.org/10.1140/epja/s10050-020-00171-3

Regular Article - Experimental Physics

Shape coexistence revealed in the isotope $^{72}$ Kr through inelastic scattering

K. Wimmer¹^,2^,3^*, T. Arici⁴^,5, W. Korten⁶, P. Doornenbal², J.-P. Delaroche⁷, M. Girod⁷, J. Libert⁷, T. R. Rodríguez⁸, P. Aguilera⁹, A. Algora¹⁰^,11, T. Ando¹, H. Baba², B. Blank¹², A. Boso¹³, S. Chen², A. Corsi⁶, P. Davies¹⁴, G. de Angelis¹⁵, G. de France¹⁶, D. T. Doherty⁶, J. Gerl⁴, R. Gernhäuser¹⁷, T. Goigoux¹², D. Jenkins¹⁴, G. Kiss²^,11, S. Koyama¹, T. Motobayashi², S. Nagamine¹, M. Niikura¹, S. Nishimura², A. Obertelli⁶, D. Lubos¹⁷, V. H. Phong², B. Rubio¹⁰, E. Sahin¹⁸, T. Y. Saito¹, H. Sakurai¹^,2, L. Sinclair¹⁴, D. Steppenbeck², R. Taniuchi¹, V. Vaquero³, R. Wadsworth¹⁴, J. Wu² and M. Zielinska⁶

¹ Department of Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
² RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
³ Instituto de Estructura de la Materia, CSIC, 28006, Madrid, Spain
⁴ GSI Helmholtzzentrum für Schwerionenforschung, 64291, Darmstadt, Germany
⁵ Justus-Liebig-Universität Giessen, 35392, Giessen, Germany
⁶ IRFU, CEA, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
⁷ CEA, DAM, DIF, 91297, Arpajon, France
⁸ Departamento de Física Teórica and Centro de Investigación Avanzada en Física Fundamental, Universidad Autónoma de Madrid, 28049, Madrid, Spain
⁹ Comisión Chilena de Energía Nuclear, Casilla 188-D, Santiago, Chile
¹⁰ Instituto de Fisica Corpuscular, CSIC-Universidad de Valencia, 46071, Valencia, Spain
¹¹ Institute for Nuclear Research (Atomki), Debrecen, 4001, Hungary
¹² CENBG, CNRS/IN2P3, Université de Bordeaux, 33175, Gradignan, France
¹³ Istituto Nazionale di Fisica Nucleare, Sezione di Padova, 35131, Padua, Italy
¹⁴ Department of Physics, University of York, York, YO10 5DD, UK
¹⁵ Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020, Legnaro, Italy
¹⁶ GANIL, CEA/DSM-CNRS/IN2P3, 14076, Caen Cedex 05, France
¹⁷ Physik Department, Technische Universität München, 85748, Garching, Germany
¹⁸ Department of Physics, University of Oslo, PO Box 1048, Blindern, Oslo, 0316, Norway

^* e-mail: k.wimmer@csic.es

Received: 2 March 2020
Accepted: 21 May 2020
Published online: 3 June 2020

Abstract

The $$N=Z=36$$ nucleus $^{72}$ Kr has been studied by inelastic scattering at intermediate energies. Two targets, $^{9}$ Be and $^{197}$ Au, were used to extract the nuclear deformation length, $\delta _\text {N}$ , and the reduced E2 transition probability, B(E2). The previously unknown non-yrast $$2^+$$ and $$4^+$$ states as well as a new candidate for the octupole $$3^-$$ state have been observed in the scattering on the Be target and placed in the level scheme based on $\gamma -\gamma$ coincidences. The second $$2^+$$ state was also observed in the scattering on the Au target and the $B(E2;\;2^+_2 \rightarrow 0^+_1)$ value could be determined for the first time. Analyzing the results in terms of a two-band mixing model shows clear evidence for a oblate-prolate shape coexistence and can be explained by a shape change from an oblate ground state to prolate deformed yrast band from the first $$2^+$$ state. This interpretation is corroborated by beyond mean field calculations using the Gogny D1S interaction.