First Results from CUORE: A Search for Lepton Number Violation via $0\nu\beta\beta$ Decay of $^{130}$Te

TL;DR

The CUORE experiment conducted its first high-sensitivity search for neutrinoless double-beta decay of $^{130}$Te, setting the most stringent lower limit on the decay half-life and constraining the effective Majorana neutrino mass.

Contribution

This work presents the first results from CUORE using a ton-scale cryogenic bolometer array for lepton-number violation search, achieving unprecedented sensitivity and setting new limits on decay half-life.

Findings

No evidence for neutrinoless double-beta decay was observed.

Lower limit on decay half-life: > $1.5 imes 10^{25}$ years (90% C.L.).

Effective Majorana neutrino mass constrained to < 110-520 meV.

Abstract

The CUORE experiment, a ton-scale cryogenic bolometer array, recently began operation at the Laboratori Nazionali del Gran Sasso in Italy. The array represents a significant advancement in this technology, and in this work we apply it for the first time to a high-sensitivity search for a lepton-number--violating process: $^{130}$Te neutrinoless double-beta decay. Examining a total TeO$_2$ exposure of 86.3 kg$\cdot$yr, characterized by an effective energy resolution of (7.7 $\pm$ 0.5) keV FWHM and a background in the region of interest of (0.014 $\pm$ 0.002) counts/(keV$\cdot$kg$\cdot$yr), we find no evidence for neutrinoless double-beta decay. The median statistical sensitivity of this search is $7.0\times10^{24}$ yr. Including systematic uncertainties, we place a lower limit on the decay half-life of $T^{0\nu}_{1/2}$($^{130}$Te) > $1.3\times 10^{25}$ yr (90% C.L.). Combining this result with those of two earlier experiments, Cuoricino and CUORE-0, we find $T^{0\nu}_{1/2}$($^{130}$Te) > $1.5\times 10^{25}$ yr (90% C.L.), which is the most stringent limit to date on this decay. Interpreting this result as a limit on the effective Majorana neutrino mass, we find $m_{\beta\beta}<(110 - 520)$ meV, where the range reflects the nuclear matrix element estimates employed.