Evaluation of Phenomenological Characteristics of the Two-Proton Decay of the 45Fe Nucleus

Abstract: A Green-function formalism describing sequential and virtual two-proton (2p) radi-oactivity is developed on the basis of the multiparticle theory of one-proton decay. In the proposed approach, two-proton emission is treated as two consecutive one-proton transitions connected by the Green's function of the intermediate nucleus, al-lowing both on-shell and off-shell intermediate states to be consistently included. Analytical expressions are derived for the total and partial 2p-decay widths as well as for the angular distribution of the emitted protons. The formalism is applied to the ground-state two-proton decay of 45Fe leading to the ground state of 43Cr within the superfluid nuclear model. Calculations demonstrate a pronounced dependence of the decay characteristics on the choice of the single-particle nuclear potential. It is shown that an appropriate choice of the shell potential allows the experimental decay width and the measured proton angular distribution to be reproduced simultaneously. These results indicate that the proposed Green-function approach provides a consistent description of virtual sequential two-proton decay and offers an alternative framework for the interpretation of true two-proton radioactivity.