Improved search for invisible modes of nucleon decay in water with the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>SNO</mml:mi><mml:mo>+</mml:mo><mml:mtext>detector</mml:mtext></mml:mrow></mml:math>
A. Allega, M. R. Anderson, S. Andringa, M. Askins, D. J. Auty, A. Bacon, N. Barros, F. Barão, N. Barros, E. W. Beier, T. S. Bezerra, A. Białek, S. D. Biller, E. Blucher, E. Caden, E. J. Callaghan, S. H. Cheng, M. Chen, O. Chkvorets, B. T. Cleveland, D. Cookman, J. Corning, M. A. Cox, R. Dehghani, C. Deluce, M. M. Depatie, J. Dittmer, K. H. Dixon, F. Di Lodovico, E. Falk, N. Fatemighomi, R. Ford, K. Frankiewicz, A. Gaur, O. I. González-Reina, D. Gooding, C. Grant, J. E. Grove, A. L. Hallin, D. Hallman, J. Hartnell, W. J. Heintzelman, R. L. Helmer, Jie Hu, R. Hunt-Stokes, SA Hussain, A. S. Inácio, C. J. Jillings, T. Kaptanoglu, P. Khaghani, Hamza Khan, J. R. Klein, L. L. Kormos, B. Krar, C. Kraus, C. B. Krauss, Tereza Kroupova, I. Lam, Benjamin Land, I. Lawson, L. Lebanowski, J. Lee, C. Lefebvre, J. Lidgard, Yen-Hsun Lin, V. Lozza, M. Luo, A. Maio, S. Manecki, J. Maneira, R. D. Martín, N. McCauley, A. B. McDonald, M. Meyer, C. Mills, I. Morton-Blake, S. Naugle, L. J. Nolan, H. M. O’Keeffe, G. D. Orebi Gann, J. Page, William C. Parker, J. Paton, S. J. M. Peeters, L. Pickard, P. Ravi, A. Reichold, S. Riccetto, R. Richardson, M. Rigan, J. Rose, J. Rumleskie, I. Semenec, P. Skensved, M. Smiley, R. Svoboda, B. Tam, J. C-L. Tseng, E. Turner, S. Valder
Abstract
This paper reports results from a search for single and multinucleon disappearance from the $^{16}\mathrm{O}$ nucleus in water within the $\mathrm{SNO}+$ detector using all of the available data. These so-called ``invisible'' decays do not directly deposit energy within the detector but are instead detected through their subsequent nuclear deexcitation and gamma-ray emission. New limits are given for the partial lifetimes: $\ensuremath{\tau}(n\ensuremath{\rightarrow}\mathrm{inv})>\phantom{\rule{0ex}{0ex}}9.0\ifmmode\times\else\texttimes\fi{}{10}^{29}\text{ }\text{ }\mathrm{years}$, $\ensuremath{\tau}(p\ensuremath{\rightarrow}\mathrm{inv})>9.6\ifmmode\times\else\texttimes\fi{}{10}^{29}\text{ }\text{ }\mathrm{years}$, $\ensuremath{\tau}(nn\ensuremath{\rightarrow}\mathrm{inv})>1.5\ifmmode\times\else\texttimes\fi{}{10}^{28}\text{ }\text{ }\mathrm{years}$, $\ensuremath{\tau}(np\ensuremath{\rightarrow}\mathrm{inv})>\phantom{\rule{0ex}{0ex}}6.0\ifmmode\times\else\texttimes\fi{}{10}^{28}\text{ }\text{ }\mathrm{years}$, and $\ensuremath{\tau}(pp\ensuremath{\rightarrow}\mathrm{inv})>1.1\ifmmode\times\else\texttimes\fi{}{10}^{29}\text{ }\text{ }\mathrm{years}$ at 90% Bayesian credibility level (with a prior uniform in rate). All but the ($nn\ensuremath{\rightarrow}\mathrm{inv}$) results improve on existing limits by a factor of about 3.