Shape Changes in the Mirror Nuclei <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Kr</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>70</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Se</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>70</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math>
K. Wimmer, W. Korten, P. Doornenbal, T. Arıcı, P. Aguilera, A. Algora, Takashi Ando, H. Baba, Β. 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. G. Jenkins, S. Koyama, T. Motobayashi, S. Nagamine, M. Nııkura, A. Obertelli, J. Libert, D. Lubos, T. Rodrı́guez, B. Rubio, E. Şahin, Takeshi Saito, H. Sakuraï, L. Sinclair, D. Steppenbeck, R. Taniuchi, R. Wadsworth, M. Zielińska
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^{+}→2^{+}). Comparison with the other members of the A=70 isospin triplet, ^{70}Br and ^{70}Se, studied in the same experiment, shows a 3σ 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.