Constraints on the energy spectrum of the diffuse cosmic neutrino flux from the ANTARES neutrino telescope

Albert, A.; Alves, S.; Andre, M.; Ardid, M.; Ardid, S.; Aubert, J. -J.; Aublin, J.; Baret, B.; Basa, S.; Becherini, Y.; Belhorma, B.; Bendahman, M.; Benfenati, F.; Bertin, V.; Biagi, S.; Boumaaza, J.; Bouta, M.; Bouwhuis, M. C.; Branzas, H.; Bruijn, R.; Brunner, J.; Busto, J.; Caiffi, B.; Calvo, D.; Campion, S.; Capone, A.; Carenini, F.; Carr, J.; Carretero, V.; Cartraud, T.; Celli, S.; Cerisy, L.; Chabab, M.; Cherkaoui El Moursli, R.; Chiarusi, T.; Circella, M.; Coelho, J. A. B.; Coleiro, A.; Coniglione, R.; Coyle, P.; Creusot, A.; Diaz, A. F.; De Martino, B.; Distefano, C.; Di Palma, I.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; Eddymaoui, A.; van Eeden, T.; van Eijk, D.; El Hedri, S.; El Khayati, N.; Enzenhofer, A.; Fermani, P.; Ferrara, G.; Filippini, F.; Fusco, L. A.; Gagliardini, S.; Garcia, J.; Gatius Oliver, C.; Gay, P.; Geisselbrecht, N.; Glotin, H.; Gozzini, R.; Gracia Ruiz, R.; Graf, K.; Guidi, C.; Haegel, L.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hennig, L.; Hernandez-Rey, J. J.; Hossl, J.; Huang, F.; Illuminati, G.; Jisse-Jung, B.; de Jong, M.; de Jong, P.; Kadler, M.; Kalekin, O.; Katz, U.; Kouchner, A.; Kreykenbohm, I.; Kulikovskiy, V.; Lahmann, R.; Lamoureux, M.; Lazo, A.; Lefevre, D.; Leonora, E.; Levi, G.; Le Stum, S.; Loucatos, S.; Manczak, J.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martinez-Mora, J. A.; Migliozzi, P.; Moussa, A.; Muller, R.; Navas, S.; Nezri, E.; Fearraigh, B. O.; Oukacha, E.; Paun, A.; Pavalas, G. E.; Pena-Martinez, S.; Perrin-Terrin, M.; Piattelli, P.; Poire, C.; Popa, V.; Pradier, T.; Randazzo, N.; Real, D.; Riccobene, G.; Romanov, A.; Sanchez Losa, A.; Saina, A.; Salesa Greus, F.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schussler, F.; Seneca, J.; Spurio, M.; Stolarczyk, T. H.; Taiuti, M.; Tayalati, Y.; Vallage, B.; Vannoye, G.; Van Elewyck, V.; Viola, S.; Vivolo, D.; Wilms, J.; Zavatarelli, S.; Zegarelli, A.; Zornoza, J. D.; Zuniga, J.

doi:10.1088/1475-7516/2024/08/038

High-significance evidences of the existence of a high-energy diffuse flux of cosmic neutrinos have emerged in the last decade from several observations by the IceCube Collaboration. The ANTARES neutrino telescope took data for 15 years in the Mediterranean Sea, from 2007 to 2022, and collected a high-purity all-flavour neutrino sample. The search for a diffuse cosmic neutrino signal using this dataset is presented in this article. This final analysis did not provide a statistically significant observation of the cosmic diffuse flux. However, this is converted into limits on the properties of the cosmic neutrino spectrum. In particular, given the sensitivity of the ANTARES neutrino telescope between 1 and 50TeV, constraints on single-power-law hypotheses are derived for the cosmic diffuse flux below 20TeV, especially for power-law fits of the IceCube data with spectral index softer than 2.8.