Measurement of the 2$\nu\beta\beta$ Decay Half-Life of Se-82 with the Global CUPID-0 Background Model

TL;DR

This paper presents a precise measurement of the two-neutrino double beta decay half-life of Se-82 using the CUPID-0 detector, improving background understanding for future neutrinoless double beta decay searches.

Contribution

The study provides the most accurate measurement to date of Se-82's 2νββ decay half-life and enhances background modeling for next-generation experiments.

Findings

Measured half-life: (8.69 ± 0.05 (stat.) +0.09/-0.06 (syst.)) × 10^{19} years.

Improved background source identification in the 3 MeV region.

Enhanced foundation for background reduction in future CUPID experiments.

Abstract

We report on the results obtained with the global CUPID-0 background model, which combines the data collected in the two measurement campaigns for a total exposure of 8.82~kg$\times$yr of $^{82}$Se. We identify with improved precision the background sources within the 3 MeV energy region, where neutrinoless double $\beta$-decay of $^{82}$Se and $^{100}$Mo is expected, making more solid the foundations for the background budget of the next-generation CUPID experiment. Relying on the excellent data reconstruction, we measure the two-neutrino double $\beta$-decay half-life of $^{82}$Se with unprecedented accuracy: $T_{1/2}^{2\nu} = [8.69 \pm 0.05 \textrm{(stat.)}~^{+0.09}_{-0.06} \textrm{(syst.)}] \times 10^{19}~\textrm{yr}$.