Doubly-magic character of 132Sn studied via electromagnetic moments of 133Sn

We report the first measurement of the magnetic dipole and electric quadrupole moment of the exotic nucleus $^{133}\mathrm{Sn}$ by high-resolution laser spectroscopy at ISOLDE/CERN. These, in combination with state-of-the-art shell-model calculations, demonstrate the single-particle character of the ground state of this short-lived isotope and, hence, the doubly-magic character of its immediate neighbor $^{132}\mathrm{Sn}$. The trend of the electromagnetic moments along the $N=83$ isotonic chain, now enriched with the values of tin, are discussed on the basis of realistic shell-model calculations.