Nuclear deformation in the A≈100 region: Comparison between new masses and mean-field predictions

An extension of the atomic mass surface in the region A≈100 was performed via measurements of the $^{100−102}$Sr and $^{100−102}$Rb masses with the ion-trap spectrometer ISOLTRAP at CERN-ISOLDE, including the first direct mass determination of $^{100−102}$Sr and $^{100−102}$Rb. These measurements confirm the continuation of the region of deformation with the increase of neutron number, at least as far as $N=65$. To interpret the deformation in the strontium isotopic chain and to determine whether an onset of deformation is present in heavier krypton isotopes, a comparison is made between the experimental values and mean-field and beyond mean-field results available in the literature. To complete this comparison Hartree-Fock-Bogoliubov calculations for even and odd isotopes were performed, illustrating the competition of nuclear shapes in the region.