Measurement of the $2\nu \beta \beta$ decay rate and spectral shape of ${}^{100}$Mo from the CUPID-Mo experiment

Abstract

Neutrinoless double beta decay ($0\nu \beta \beta$) is a yet unobserved nuclear process which would demonstrate Lepton Number violation, a clear evidence of beyond Standard Model physics. The process two neutrino double beta decay ($2\nu \beta \beta )$ is allowed by the Standard Model and has been measured in numerous experiments. In this letter, we report a measurement of $2\nu \beta \beta$ decay half-life of ${}^{100}$Mo to the ground state of ${}^{100}$Ru of $(7.07\pm 0.02\text{(stat.)}\pm 0.11\text{(syst.)})\times 10^{18}$~yr by the CUPID-Mo experiment. With a relative precision of $\pm 1.6$ \% this is the most precise measurement to date of a $2\nu \beta \beta$ decay rate in ${}^{100}$Mo. In addition, we constrain higher-order corrections to the spectral shape which provides complementary nuclear structure information. We report a novel measurement of the shape factor ${\xi }_{3,1}=0.45\pm 0.03\text{(stat.)}\pm 0.05\text{(syst.)}$, which is compared to theoretical predictions for different nuclear models. We also extract the first value for the effective axial vector coupling constant obtained from a spectral shape study of $2\nu \beta \beta$ decay.

arXiv comment8 pages, 5 figures

References in corpus (18)

• Status and Future of Nuclear Matrix Elements for Neutrinoless Double-Beta Decay: A Review
• Phase space factors for double-$\beta$ decay
• $0\nu \beta \beta$ and $2\nu \beta \beta$ nuclear matrix elements, QRPA, and isospin symmetry restoration
• Toward the discovery of matter creation with neutrinoless double-beta decay
• The effective g_A in the pf-shell
• Value of the axial-vector coupling strength in $\beta$ and $\beta \beta$ decays: A review
• Discovery probability of next-generation neutrinoless double-$\beta$ decay experiments
• The CUPID-Mo experiment for neutrinoless double-beta decay: performance and prospects
• Two-neutrino double beta decay of 76Ge within deformed QRPA: A new suppression mechanism
• Precision Analysis of the ${}^{136}$Xe Two-Neutrino $\beta \beta$ Spectrum in KamLAND-Zen and Its Impact on the Quenching of Nuclear Matrix Elements
• Improved description of the $2\nu \beta \beta$-decay and a possibility to determine the effective axial-vector coupling constant
• The Single State Dominance Hypothesis and the Two-Neutrino Double Beta Decay of Mo100
• Muon-induced background in the EDELWEISS dark matter search
• Double-beta decay investigation with highly pure enriched ${}^{82}$Se for the LUCIFER experiment
• Measurement of the 2$\nu \beta \beta$ Decay Half-life of ${}^{130}$Te with CUORE
• Shell-model calculation of ${}^{100}$Mo double-$\beta$ decay
• Effective Majorana Mass and Neutrinoless Double Beta Decay
• Pulse Shape Discrimination in CUPID-Mo using Principal Component Analysis

Cited by in corpus (1)

• First demonstration of a TES based cryogenic Li${}_2$MoO${}_4$detector for neutrinoless double beta decay search