Low-energy structure and anti-bubble effect of dynamical correlations in 46 Ar

The low-energy structure of 46Ar is of particular interest due to the possible coexistence of different shapes and the possible existence of proton "bubble" structures. In this work, we apply a beyond relativistic mean-field approach to study the low-energy structure of 46Ar. Correlations beyond the mean field are introduced by configuration mixing of both particle-number and angular-momentum projected axially deformed mean-field states. The low-lying spectroscopy and charge density in a laboratory frame are calculated and an excellent agreement with available data is achieved. Even though an evident proton bubble structure is shown in the spherical state of 46Ar, it eventually disappears after taking into account the dynamical correlation effects. Moreover, our results indicate that the existence of a proton bubble structure in argon isotopes is unlikely.