Improved Limit on Neutrinoless Double-Beta Decay in $^{130}$Te with CUORE

TL;DR

The CUORE experiment's improved search for neutrinoless double-beta decay in $^{130}$Te sets a new lower half-life limit of 3.2×10^{25} years, constraining neutrino mass models without observing decay.

Contribution

This work provides the most stringent limit to date on neutrinoless double-beta decay in $^{130}$Te using enhanced detector exposure and analysis techniques.

Findings

No evidence for neutrinoless double-beta decay was observed.

Set a new lower limit on the decay half-life of 3.2×10^{25} years.

Constrained the effective Majorana neutrino mass to 75-350 meV.

Abstract

We report new results from the search for neutrinoless double-beta decay in $^{130}$Te with the CUORE detector. This search benefits from a four-fold increase in exposure, lower trigger thresholds and analysis improvements relative to our previous results. We observe a background of $(1.38\pm0.07)\cdot10^{-2}$ counts$/($keV$\cdot$kg$\cdot$yr$)$ in the $0\nu\beta\beta$ decay region of interest and, with a total exposure of 372.5 kg$\cdot$yr, we attain a median exclusion sensitivity of $1.7\cdot10^{25}$ yr. We find no evidence for $0\nu\beta\beta$ decay and set a $90\%$ CI Bayesian lower limit of $3.2\cdot10^{25}$ yr on the $^{130}$Te half-life for this process. In the hypothesis that $0\nu\beta\beta$ decay is mediated by light Majorana neutrinos, this results in an upper limit on the effective Majorana mass of 75-350 meV, depending on the nuclear matrix elements used.