Phenomenological features of two-proton virtual decay of the 45 Fe nucleus
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CLEI Theory
Phenomenological Features of Two-Proton Virtual Decay of the 45 Fe Nucleus S. G. Kadmensky* , Yu. V. Ivankov, and D. E. Lyubashevsky Voronezh State University, Universitetskaya pl. 1, Voronezh, 394036 Russia Received January 18, 2017
Abstract—On the basis of the theory of diagonal two-proton two-step virtual decays of spherical nuclei that was developed earlier and the superfluid model of the nucleus, the total and partial widths for the two-proton decay of the 45 Fe parent nucleus in the ground state to the ground state of the 43 Cr daughter nucleus were calculated along with the angular distribution of protons emitted in this decay. The calculated features of this mode of 45 Fe decay were shown to be highly sensitive to the choice of form for nucleon shell potentials. It is also shown that there exists a potential such with which one can construct a successful simultaneous description of the experimental total width and the angular distribution of emitted protons for the aforementioned two-proton mode of decay of the 45 Fe nucleus. DOI: 10.1134/S1063778817050143
1. INTRODUCTION The two-proton radioactivity phenomenon predicted earlier [1] was first discovered for the 45 Fe nucleus [2, 3] and was then found for a number of other nuclei. The total width Γ [2, 3] for the twoproton decay of the even–odd 45 Fe nucleus in the ground state to the ground state of the even–odd 43 Cr final nucleus has been measured experimentally to date along with the energy [4] and angular [5, 6] distributions of protons emitted in this decay. There is a serious discrepancy between the above experimentally measured features and their counterparts calculated on the basis of the diproton model [7], which admits the appearance of a virtual s-wave state [8– 10] of two emitted protons. At the same time, these features were described qualitatively on the basis of the R-matrix approach developed in [11], where the two-proton decay mode is treated as a three-body decay process in which the parent nucleus emits simultaneously two protons, transforming into the daughter nucleus. The respective calculations were performed via expanding three-body wave functions in terms of hyperspherical harmonics and via constructing the interaction of three particles in terms of two-particle Coulomb and nuclear potentials and an effective three-particle short-range potential. Unfortunately, the connection between the effective potentials chosen for describing three-particle systems, on one hand, and shell potentials traditionally used in *
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describing states of multinucleon nuclei and potentials of superfluid nucleon–nucleon interactions, on the other hand, was not studied within the approaches developed in [11]. Therefore, it is not clear whether one can match the effective potentials chosen in [11] with traditional ones or whether it is necessary to revisit the parameters of the traditional potentials with the aim of describing the phenomenon of two-proton radioactivity. A theory of two-step two-proton decays of nuclei was d
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