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arXiv · 2203.13042

Two-neutrino double-$β$ decay in the mapped interacting boson model

Kosuke Nomura
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Abstract

A calculation of two-neutrino double-$β$ ($2νββ$) decay matrix elements within the interacting boson model (IBM) that is based on the nuclear density functional theory is presented. The constrained self-consistent mean-field (SCMF) calculation using a universal energy density functional (EDF) and a pairing interaction provides potential energy surfaces with triaxial quadrupole degrees of freedom for even-even nuclei corresponding to the initial and final states of the $2νββ$ decays of interest. The SCMF energy surface is then mapped onto the bosonic one, and this procedure determines the IBM Hamiltonian for the even-even nuclei. The same SCMF calculation provides the essential ingredients of the interacting boson fermion-fermion model (IBFFM) for the intermediate odd-odd nuclei and the Gamow-Teller and Fermi transition operators. The EDF-based IBM and IBFFM provide a simultaneous description of excitation spectra and electromagnetic transition rates for each nucleus, and single-$β$ and $ββ$ decay properties. The calculated $2νββ$-decay nuclear matrix elements are compared with experiment and with those from earlier theoretical calculations.

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Kosuke Nomura. 2022-04-05. Two-neutrino double-$β$ decay in the mapped interacting boson model. https://doi.org/10.1103/physrevc.105.044301

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