New Results on 0νββ Decay from the CUORE Experiment

Abstract

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay (0νββ) that has successfully reached the tonne mass scale. The detector, located at the LNGS in Italy, consists of an array of 988 TeO2 crystals arranged in a compact cylindrical structure of 19 towers. CUORE began its first physics data run in 2017 at a base temperature of about 10 mK and has been collecting data continuously since 2019, reaching a TeO2 exposure of 2 tonne- year in spring 2023. This is the largest amount of data ever acquired with a solid-state cryogenic detector, which allows for a significant improvement in the sensitivity to 0νββ decay in 130Te. In this article, we present the analysis of new CUORE data, corresponding to ∼1 tonne · yr TeO2 exposure. This analysis relies on significant enhancements to the data processing chain and high-level analysis. Combining the new data with the former data release, we find no evidence for 0νββ decay and set a preliminary 90% credibility interval Bayesian lower limit of 3.3 · 1025 yr on the 130Te half-life for this process. In the hypothesis that 0νββ decay is mediated by light Majorana neutrinos, this results in an upper limit on the effective Majorana mass of 75–255 meV, depending on the nuclear matrix element used.

Keywords

• neutrinoless double beta decay
• rare events
• cryogenic detectors