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arXiv · 1904.01148

Measurement of neutron production in atmospheric neutrino interactions at the Sudbury Neutrino Observatory

Abstract

Neutron production in GeV-scale neutrino interactions is a poorly studied process. We have measured the neutron multiplicities in atmospheric neutrino interactions in the Sudbury Neutrino Observatory experiment and compared them to the prediction of a Monte Carlo simulation using GENIE and a minimally modified version of GEANT4. We analyzed 837 days of exposure corresponding to Phase I, using pure heavy water, and Phase II, using a mixture of Cl in heavy water. Neutrons produced in atmospheric neutrino interactions were identified with an efficiency of $15.3\%$ and $44.3\%$, for Phase I and II respectively. The neutron production is measured as a function of the visible energy of the neutrino interaction and, for charged current quasi-elastic interaction candidates, also as a function of the neutrino energy. This study is also performed classifying the complete sample into two pairs of event categories: charged current quasi-elastic and non charged current quasi-elastic, and $ν_μ$ and $ν_e$. Results show good overall agreement between data and Monte Carlo for both phases, with some small tension with a statistical significance below $2σ$ for some intermediate energies.

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SNO Collaboration, B. Aharmim, S. N. Ahmed, A. E. Anthony, N. Barros, E. W. Beier, A. Bellerive, B. Beltran, M. Bergevin, S. D. Biller, R. Bonventre, K. Boudjemline, M. G. Boulay, B. Cai, E. J. Callaghan, J. Caravaca, Y. D. Chan, D. Chauhan, M. Chen, B. T. Cleveland, G. A. Cox, X. Dai, H. Deng, F. B. Descamps, J. A. Detwiler, P. J. Doe, G. Doucas, P. -L. Drouin, M. Dunford, S. R. Elliott, H. C. Evans, G. T. Ewan, J. Farine, H. Fergani, F. Fleurot, R. J. Ford, J. A. Formaggio, N. Gagnon, K. Gilje, J. TM. Goon, K. Graham, E. Guillian, S. Habib, R. L. Hahn, A. L. Hallin, E. D. Hallman, P. J. Harvey, R. Hazama, W. J. Heintzelman, J. Heise, R. L. Helmer, A. Hime, C. Howard, M. Huang, P. Jagam, B. Jamieson, N. A. Jelley, M. Jerkins, K. J. Keeter, J. R. Klein, L. L. Kormos, M. Kos, A. Kruger, C. Kraus, C. B. Krauss, T. Kutter, C. C. M. Kyba, B. J. Land, R. Lange, J. Law, I. T. Lawson, K. T. Lesko, J. R. Leslie, I. Levine, J. C. Loach, R. MacLellan, S. Majerus, H. B. Mak, J. Maneira, R. D. Martin, A. Mastbaum, N. McCauley, A. B. McDonald, S. R. McGee, M. L. Miller, B. Monreal, J. Monroe, B. G. Nickel, A. J. Noble, H. M. O'Keeffe, N. S. Oblath, C. E. Okada, R. W. Ollerhead, G. D. Orebi Gann, S. M. Oser, R. A. Ott, S. J. M. Peeters, A. W. P. Poon, G. Prior, S. D. Reitzner. 2019-06-19. Measurement of neutron production in atmospheric neutrino interactions at the Sudbury Neutrino Observatory. https://doi.org/10.1103/physrevd.99.112007

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