Measurement of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Xe</mml:mi><mml:mprescripts/><mml:none/><mml:mn>136</mml:mn></mml:mmultiscripts></mml:math> two-neutrino double-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>β</mml:mi></mml:math>-decay half-life via direct background subtraction in NEXT
P. Novella, M. Sorel, A. Usón, C. Adams, H. Almazán, V. Álvarez, B. Aparicio, A. I. Aranburu, L. Arazi, I. J. Arnquist, S. Ayet, C.D.R. Azevedo, K. Bailey, F. Ballester, J. M. Benlloch-Rodríguez, F.I.G.M. Borges, S. Bounasser, N. Byrnes, S. Cárcel, J. V. Carrión, S. Cebrián, E. Church, C.A.N. Conde, T. Contreras, Fernando P. Cossío, A. A. Denisenko, G. Díaz, J. Dı́az, T. Dickel, J. Escada, R. Esteve, A. Fahs, R. Felkai, L. M. P. Fernandes, P. Ferrario, A. L. Ferreira, Frank W. Foss, E.D.C. Freitas, Zoraida Freixa, J. Generowicz, A. Goldschmidt, J.J. Gómez-Cadenas, R. González, D. González-Díaz, R. Guenette, Raquel Morentín Gutiérrez, J. Haefner, K. Hafidi, J. Hauptman, C. A. O. Henriques, J. A. Hernando Morata, P. Herrero-Gómez, V. Herrero, J. Ho, Y. Ifergan, B. J. P. Jones, M. Kekic, L. Labarga, A. Laing, L. Larizgoitia, P. Lebrun, D. Lopez Gutierrez, N. López-March, M. Losada, R. D. P. Mano, J. Martín-Albo, A. Martínez, G. Martínez-Lema, M. Martínez-Vara, A. D. McDonald, Z. E. Meziani, K. Mistry, F. Monrabal, C. M. B. Monteiro, Francisco Mora, J. Muñoz Vidal, K. Navarro, D. R. Nygren, E. Oblak, Mikel Odriozola‐Gimeno, B. Palmeiro, A. Para, Juan C. Pérez, M. Querol, A. Raymond, A. B. Redwine, J. Renner, L. Ripoll, Iván Rivilla, Y. Rodríguez García, J. Rodríguez, Celia Rogero, L. Rogers, B. Romeo, C. Romo-Luque, F.P. Santos, J.M.F. dos Santos, A. Simón, C. Stanford, J. M. R. Teixeira
Abstract
We report a measurement of the half-life of the $^{136}\mathrm{Xe}$ two-neutrino double-$\ensuremath{\beta}$ decay performed with a novel direct-background-subtraction technique. The analysis relies on the data collected with the NEXT-White detector operated with $^{136}\mathrm{Xe}$-enriched and $^{136}\mathrm{Xe}$-depleted xenon, as well as on the topology of double-electron tracks. With a fiducial mass of only 3.5 kg of Xe, a half-life of $2.{34}_{\ensuremath{-}0.46}^{+0.80}{\text{(stat)}}_{\ensuremath{-}0.17}^{+0.30}\text{(sys)}\ifmmode\times\else\texttimes\fi{}{10}^{21}\phantom{\rule{3.33333pt}{0ex}}\text{yr}$ is derived from the background-subtracted energy spectrum. The presented technique demonstrates the feasibility of unique background-model-independent neutrinoless double-$\ensuremath{\beta}$-decay searches.