Determining the neutrino mass ordering and oscillation parameters with KM3NeT/ORCA

• Published in: The European Physical Journal C
• Main Authors: Aiello, S., Albert, A., Garre, S. Alves, Aly, Z., Ambrosone, A., Ameli, F., Andre, M., Androulakis, G., Anghinolfi, M., Anguita, M., Anton, G., Ardid, M., Ardid, S., Aublin, J., Bagatelas, C., Baret, B., Basegmez Du Pree, S., Bendahman, M., Benfenati, F., Berbee, E., van den Berg, A.M., Bertin, V., Biagi, S., Bissinger, M., Boettcher, M., Cabo, M. Bou, Boumaaza, J., Bouta, M., Bouwhuis, M., Bozza, C., Brânzaş, H., Bruijn, R., Brunner, J., Bruno, R., Buis, E., Buompane, R., Busto, J., Caiffi, B., Calvo, D., Capone, A., Carretero, V., Castaldi, P., Celli, S., Chabab, M., Chau, N., Chen, A., Cherubini, S., Chiarella, V., Chiarusi, T., Circella, M.
• Other Authors: Groupe de Recherche en Physique des Hautes Energies (GRPHE), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut Universitaire de Technologie de Colmar, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire de physique subatomique et des technologies associées (SUBATECH), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom Paris (IMT)-Institut Mines-Télécom Paris (IMT), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), KM3NeT
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: neutrino: mass; neutrino: oscillation; neutrino: atmosphere; neutrino: mixing angle; neutrino: mass difference; neutrino/tau: particle identification; antineutrino/tau: particle identification; sensitivity; KM3NeT; unitarity; neutrino: mixing; data analysis method; experimental results; [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]; Orca
• Online Access: https://hal.science/hal-03191157; https://doi.org/10.1140/epjc/s10052-021-09893-0

International audience The next generation of water Cherenkov neutrino telescopes in the Mediterranean Sea are under construction offshore France (KM3NeT/ORCA) and Sicily (KM3NeT/ARCA). The KM3NeT/ORCA detector features an energy detection threshold which allows to collect atmospheric neutrinos to study flavour oscillation. This paper reports the KM3NeT/ORCA sensitivity to this phenomenon. The event reconstruction, selection and classification are described. The sensitivity to determine the neutrino mass ordering was evaluated and found to be 4.4$\sigma $ if the true ordering is normal and 2.3$\sigma $ if inverted, after 3 years of data taking. The precision to measure $\varDelta m^2_{32}$ and $\theta _{23}$ were also estimated and found to be $85 . 10^{-6}~{\mathrm{eV}^{2}}$ and $(^{+1.9}_{-3.1})^{\circ }$ for normal neutrino mass ordering and, $75 . 10^{-6}~{\mathrm{eV}^{2}}$ and $(^{+2.0}_{-7.0})^{\circ }$ for inverted ordering. Finally, a unitarity test of the leptonic mixing matrix by measuring the rate of tau neutrinos is described. Three years of data taking were found to be sufficient to exclude event rate variations larger than 20% at $3\sigma $ level.