High-precision $Q$-value measurement and nuclear matrix elements for the double-$\beta$ decay of $^{98}$Mo

TL;DR

This study precisely measures the Q-value for double-beta decay of $^{98}$Mo, calculates phase-space factors, and computes nuclear matrix elements using different models, providing improved data for understanding neutrinoless double-beta decay.

Contribution

The paper provides the most precise Q-value measurement for $^{98}$Mo's double-beta decay and calculates nuclear matrix elements with two models, enhancing decay half-life predictions.

Findings

Q-value determined as 113.668(68) keV, much more precise than previous

Phase-space factors calculated for both decay modes

Predicted half-life for $^{98}$Mo decay is significantly longer

Abstract

Neutrinoless double-beta ($0\nu\beta\beta$) decay and the standard two-neutrino double-beta ($2\nu\beta\beta$) decay of $^{98}$Mo have been studied. The double-beta decay $Q$-value has been determined as $Q_{\beta\beta}=113.668(68)$ keV using the JYFLTRAP Penning trap mass spectrometer. It is in agreement with the literature value, $Q_{\beta\beta}=109(6)$ keV, but almost 90 times more precise. Based on the measured $Q$-value, precise phase-space factors for $2\nu\beta\beta$ decay and $0\nu\beta\beta$ decay, needed in the half-life predictions, have been calculated. Furthermore, the involved nuclear matrix elements have been computed in the proton-neutron quasiparticle random-phase approximation (pnQRPA) and the microscopic interacting boson model (IBM-2) frameworks. Finally, predictions for the $2\nu\beta\beta$ decay are given, suggesting a much longer half-life than for the currently observed cases.