Shape Changes in the Mirror Nuclei $^{70}Kr$ and $^{70}Se$

K. Wimmer , W. Korten (1) , P. Doornenbal , T. Arici , P. Aguilera , A. Algora , T. Ando , H. Baba , B. Blank (2) , A. Boso , S. Chen , A. Corsi (1) , P. Davies , G. de Angelis , G. de France (3) , J.P. Delaroche (4) , D.T. Doherty (1) , J. Gerl , R. Gernhäuser , M. Girod (4) , D. Jenkins , S. Koyama , T. Motobayashi , S. Nagamine , M. Niikura , A. Obertelli (1) , J. Libert (4) , D. Lubos , T.R. Rodríguez , B. Rubio , E. Sahin , T.Y. Saito , H. Sakurai , L. Sinclair , D. Steppenbeck , R. Taniuchi , R. Wadsworth , M. Zielinska (1)

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
2 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
3 GANIL - Grand Accélérateur National d'Ions Lourds
4 DAM - Direction des Applications Militaires

We studied the proton-rich Tz=-1 nucleus Kr70 through inelastic scattering at intermediate energies in order to extract the reduced transition probability, B(E2;0+→2+). Comparison with the other members of the A=70 isospin triplet, Br70 and Se70, studied in the same experiment, shows a 3σ deviation from the expected linearity of the electromagnetic matrix elements as a function of Tz. At present, no established nuclear structure theory can describe this observed deviation quantitatively. This is the first violation of isospin symmetry at this level observed in the transition matrix elements. A heuristic approach may explain the anomaly by a shape change between the mirror nuclei Kr70 and Se70 contrary to the model predictions.

Mots clés: Nuclear Physics

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Physique Nucléaire Théorique [nucl-th]

K. Wimmer, W. Korten, P. Doornenbal, T. Arici, P. Aguilera, et al.. Shape Changes in the Mirror Nuclei $^{70}Kr$ and $^{70}Se$. Physical Review Letters, 2021, 126 (7), pp.072501. ⟨10.1103/PhysRevLett.126.072501⟩. ⟨hal-03115870⟩