A Search for 0+ States in 50Cr: Implications for the Superallowed β-decay of 50Mn
Abstract
A 52Cr(p,t)50Cr two-neutron pickup reaction was performed using the Q3D magnetic spectrograph at the Maier-Leibnitz-Laboratorium in Garching, Germany. Excited states in 50Cr were observed up to an excitation energy of 5.3 MeV. Despite significantly increased sensitivity and resolution over previous work, no evidence of the previously assigned first excited 0+ state was found. As a result, the 0+2 state is reassigned at an excitation energy of Ex=3895.0(5) keV in 50Cr. This reassignment directly impacts direct searches for a non-analogue Fermi β+ decay branch in 50Mn. These results also show better systematic agreement with the theoretical predictions for the 0+ state spectrum in 50Cr using the same formalism as the isospin-symmetry-breaking correction calculations for superallowed nuclei. The experimental data are also compared to ab-initio shell-model predictions using the IM-SRG formalism based on NN and 3N forces from chiral-EFT in the pf-shell for the first time.