Measurement of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>2</mml:mn><mml:mi>ν</mml:mi><mml:mi>β</mml:mi><mml:mi>β</mml:mi></mml:mrow></mml:math> Decay Half-Life of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Se</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>82</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> with the Global CUPID-0 Background Model
O Azzolini, Jeffrey W. Beeman, F. Bellini, M. Beretta, M Biassoni, C Brofferio, C. Bucci, S. Capelli, V. Caracciolo, L. Cardani, P. Carniti, N. Casali, E. Celi, D. Chiesa, M. Clemenza, I. Colantoni, O Cremonesi, A. Cruciani, A. D’Addabbo, I. Dafinei, S. Di Domizio, V Dompè, G Fantini, F Ferroni, L. Gironi, A. Giuliani, P. Gorla, Cecilia Gotti, G. Keppel, J. Kotila, M. Martínez, S.S. Nagorny, M. Nastasi, S. Nisi, C. Nones, D. Orlandi, L. Pagnanini, M Pallavicini, L. Pattavina, M. Pavan, G. Pessina, V Pettinacci, S. Pirro, S. Pozzi, E Previtali, A. Puiu, A Ressa, C. Rusconi, K. Schäffner, C. Tomei, M. Vignati, A. Zolotarova
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 $8.82\text{ }\text{ }\mathrm{kg}\ifmmode\times\else\texttimes\fi{}\mathrm{yr}$ of $^{82}\mathrm{Se}$. We identify with improved precision the background sources within the 3 MeV energy region, where neutrinoless double $\ensuremath{\beta}$ decay of $^{82}\mathrm{Se}$ and $^{100}\mathrm{Mo}$ 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 $\ensuremath{\beta}$-decay half-life of $^{82}\mathrm{Se}$ with unprecedented accuracy: ${T}_{1/2}^{2\ensuremath{\nu}}=[8.69\ifmmode\pm\else\textpm\fi{}0.05(\mathrm{stat})_{\ensuremath{-}0.06}^{+0.09}(\mathrm{syst})]\ifmmode\times\else\texttimes\fi{}{10}^{19}\text{ }\text{ }\mathrm{yr}$.