Shape changes in the mirror nuclei $^{70}$Kr and $^{70}$Se

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

doi:10.1103/physrevlett.126.072501

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arXiv · 2101.02363

Shape changes in the mirror nuclei $^{70}$Kr and $^{70}$Se

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Abstract

We studied the proton-rich $T_z=-1$ nucleus $^{70}$Kr through inelastic scattering at intermediate energies in order to extract the reduced transition probability, $B(E2;\;0^+ \rightarrow 2^+)$. Comparison with the other members of the $A=70$ isospin triplet, $^{70}$Br and $^{70}$Se, studied in the same experiment, shows a $3\sigma$ deviation from the expected linearity of the electromagnetic matrix elements as a function of $T_z$. 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 $^{70}$Kr and $^{70}$Se contrary to the model predictions.

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K. Wimmer, W. Korten, P. Doornenbal, T. Arici, P. Aguilera, A. Algora, T. Ando, H. Baba, B. Blank, A. Boso, S. Chen, A. Corsi, P. Davies, G. de Angelis, G. de France, J. -P. Delaroche, D. T. Doherty, J. Gerl, R. Gernhäuser, M. Girod, D. Jenkins, S. Koyama, T. Motobayashi, S. Nagamine, M. Niikura, A. Obertelli, J. Libert, D. Lubos, T. R. Rodríguez, B. Rubio, E. Sahin, T. Y. Saito, H. Sakurai, L. Sinclair, D. Steppenbeck, R. Taniuchi, R. Wadsworth, M. Zielinska. 2021-01-07. Shape changes in the mirror nuclei $^{70}$Kr and $^{70}$Se. https://doi.org/10.1103/physrevlett.126.072501

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