Double-beta decay to excited 0(+) states: Decay of 100Mo.

TLDR: In this paper, the authors developed a formalism for describing double-beta decay to an excited final state in the quasiparticle random phase approximation (QRPA) and deduced the half-lives for the $ 1.5 × 1.

Abstract: We develop a formalism for describing the 2\ensuremath{\nu} mode of double-beta decay to an excited final state in the quasiparticle random phase approximation (QRPA). With this, we deduce the half-lives for the $^{100}\mathrm{Mo}$ double-beta decays to both the ground and 1130 keV excited ${0}^{+}$ states in $^{100}\mathrm{Ru}$. We predict the matrix elements of these two transitions to be of a similar magnitude. We also calculate the strengths of the associated single-beta decays from the ground state of the intermediate nucleus, $^{100}\mathrm{Tc}$, and compare them with experiment. We find that the QRPA cannot simultaneously reproduce all of the experimental quantities, and, in particular, the single-beta transition between the initial and intermediate nuclei is overestimated by the theory. In addition, we demonstrate that the influence of the particle-particle force is an important factor in the calculation of both ${\mathrm{\ensuremath{\beta}}}^{\mathrm{\ensuremath{-}}}$ and ${\mathrm{\ensuremath{\beta}}}^{+}$ transition strengths.