Probing isospin symmetry in the (Fe50, Mn50, Cr50) isobaric triplet via electromagnetic transition rates

Lifetimes of the T = 1 isobaric analog I-pi = 2(+) states in Mn-50 and Cr-50 were measured simultaneously by employing the recoil distance Doppler-shift (RDDS) technique. The states were populated in a fusion- evaporation reaction with a C-12 beam on a Ca-40 target. An analysis of the data and the calculations from the present work, together with the available B(E2 : 2(+) -> 0(+)) data of the isobaric analog states in Fe-50 and Cr-50, were used to study isospin symmetry in the three A = 50 isobaric nuclei. Shell-model calculations reproduce the magnitudes as well as the increasing trend of the B(E2) data with increasing Z. To draw a firm conclusion on the level of isospin mixing in the triplet, a new precision measurement of the 2(+) -> 0(+) transition rate in Fe-50 will be required.