Relation between isospin-symmetry-breaking correction to superallowed β decay and the energy of the charge-exchange giant monopole resonance

After application of an analytical transformation, a new exact representation for the nuclear isospin-symmetry-breaking correction delta(C) to superallowed beta decay is obtained. The correction is shown to be essentially the reciprocal of the square of an energy parameter Omega(M) which characterizes the charge-exchange monopole strength distribution. The proportionality coefficient in this relation is determined by basic properties of the ground state of the even-even parent nucleus and should be reliably calculable in any realistic nuclear model. Therefore, the single parameter Omega(M) contains all the information about the properties of excited 0(+) states needed to describe delta(C). This parameter can possibly be determined experimentally by charge-exchange reactions. Basic quantities of interest are calculated within the isospin-consistent continuum random phase approximation, and the values of delta(C) are compared with the corresponding results from other approaches.