Most precise measurement of 2νββ half-life and shape of ¹³⁰Te with CUORE

The Cryogenic Underground Observatory for Rare Events (CUORE) is a tonne-scale detector searching for neutrinoless double beta decay (0νββ) in ¹³⁰Te. It consists of 988 TeO₂ crystals operated at ~15 mK at Gran Sasso National Laboratory (Italy).

A deep understanding of the backgrounds is pivotal in discovering a very rare process like the 0νββ decay. Characterizing the CUORE setup also informs the background model for CUPID, the next-generation experiment reusing the same cryogenic infrastructure. Additionally, high-precision studies of 2νββ decay allow tests and data-driven refinements of nuclear models, which currently represent the largest uncertainty on 0νββ predictions. Reducing these uncertainties would directly improve the precision on the effective Majorana mass in case of discovery, and would also provide valuable guidance for isotope down-selection in future experiments.

In this talk, I will present the first comprehensive model of the CUORE background by fitting the 1 ton·yr CUORE dataset using a simultaneous Bayesian fit of multiple energy spectra across the full energy range of the detector. I will also discuss the optimizations included to perform the most precise measurement of the ¹³⁰Te 2νββ decay to date: T_2ν^1/2 = (9.32^+0.05_-0.04 stat. ^+0.07_-0.07 syst.) ·10²⁰ yr.

Finally, I will show the first implementation of the 2νββ decay improved description to ¹³⁰Te, enabling shape studies and tests for various nuclear models, key steps toward future 0νββ discovery