Isospin mixing from β -delayed proton emission

We present a general scheme of a shell-model analysis of a β-delayed proton emission. We show that the experimental proton to γ-ray branching ratio for the isobaric analog state (IAS) populated in β decay of a precursor, supplemented by theoretical proton and γ-ray widths, can be used to extract spectroscopic factors for isospin-forbidden proton emission. In the case of a well-justified two-level mixing approximation and a relatively well known spectroscopic factor of the admixed state, the proposed scheme provides a new way to determine the amount of the isospin mixing in the IAS. This conjecture is illustrated by the theoretical analysis of Cr44 and Fe48 decay.