=Date and Place=
Apr.9th(Tue.), 13:30~ at RIBF Hall
Prof. Takaharu Otsuka
(Nuclear Spectroscopy Lab., RNC)
Tin isotopes : Are they dull round nuclei ?
I will present the picture of Sn isotopes obtained from recent studies by Monte Carlo Shell Model. This picture differs from the conventional one that the Sn isotopes, between N=50 and 82, are all spherical and are described by the condensate of isotropic Cooper pairs. Evidently, recent B(E2) measurements worldwide contradict this picture, but no systematic theoretical explanation was given before. We found that the Z=50 magic structure is substantially broken in lighter Sn isotopes, and the unexpectedly large B(E2) values can be nicely reproduced. We further realized that the Sn isotopes undergo a 2nd order quantum phase transition around N=66 from the modestly deformed phase to the spherical seniority phase. Thus, the Sn isotopes are not dull round nuclei, but provide us with a number of challenges and battle fields.