KM3NeT Collaboration(Aiello, S. et al), Alves Garre, S., Calvo, D., Carretero, V., Garcia Soto, A., Gozzini, S. R., et al. (2023). First observation of the cosmic ray shadow of the Moon and the Sun with KM3NeT/ORCA. Eur. Phys. J. C, 83(4), 344–9pp.
Abstract: This article reports the first observation of the Moon and the Sun shadows in the sky distribution of cosmicray induced muons measured by the KM3NeT/ORCA detector. The analysed data-taking period spans from February 2020 to November 2021, when the detector had 6 Detection Units deployed at the bottom of the Mediterranean Sea, each composed of 18 Digital Optical Modules. The shadows induced by theMoon and the Sun were detected at their nominal position with a statistical significance of 4.2 sigma and 6.2 sigma, and an angular resolution of sigma(res) = 0.49 degrees and sigma(res) = 0.66 degrees, respectively, consistent with the prediction of 0.53 degrees from simulations. This early result confirms the effectiveness of the detector calibration, in time, position and orientation and the accuracy of the event direction reconstruction. This also demonstrates the performance and the competitiveness of the detector in terms of pointing accuracy and angular resolution.
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Real, D., & Calvo, D. (2023). Silicon Photomultipliers for Neutrino Telescopes. Universe, 9(7), 326–14pp.
Abstract: Neutrino astronomy has opened a new window to the extreme Universe, entering into a fruitful era built upon the success of neutrino telescopes, which have already given a new step forward in this novel and growing field by the first observation of steady point-like sources already achieved by IceCube. Neutrino telescopes equipped with Silicon PhotoMultipliers (SiPMs) will significantly increase in number, because of their excellent time resolution and the angular resolution, and will be in better condition to detect more steady sources as well as the unexpected. The use of SiPMs represents a challenge to the acquisition electronics because of the fast signals as well as the high levels of dark noise produced by SiPMs. The acquisition electronics need to include a noise rejection scheme by implementing a coincidence filter between channels. This work discusses the advantages and disadvantages of using SiPMs for the next generation of neutrino telescopes, focusing on the possible developments that could help for their adoption in the near future.
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KM3NeT Collaboration(Aitllo, S. et al), Alves Garre, S., Calvo, D., Carretero, V., Garcia Soto, A., Gozzini, S. R., et al. (2023). Probing invisible neutrino decay with KM3NeT/ORCA. J. High Energy Phys., 04(4), 090–30pp.
Abstract: In the era of precision measurements of the neutrino oscillation parameters, upcoming neutrino experiments will also be sensitive to physics beyond the Standard Model. KM3NeT/ORCA is a neutrino detector optimised for measuring atmospheric neutrinos from a few GeV to around 100 GeV. In this paper, the sensitivity of the KM3NeT/ORCA detector to neutrino decay has been explored. A three-flavour neutrino oscillation scenario, where the third neutrino mass state v3 decays into an invisible state, e.g. a sterile neutrino, is considered. We find that KM3NeT/ORCA would be sensitive to invisible neutrino decays with 1/alpha 3 = T3/m3 < 180 ps/eV at 90% confidence level, assuming true normal ordering. Finally, the impact of neutrino decay on the precision of KM3NeT/ORCA measurements for theta(23), Delta m(31)(2) and mass ordering have been studied. No significant effect of neutrino decay on the sensitivity to these measurements has been found.
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AMON Team, A. N. T. A. R. E. S. and H. A. W. C. C.(A. S., H.A. et al), Alves Garres, S., Calvo, D., Carretero, V., Gozzini, R., Hernandez-Rey, J. J., et al. (2023). Search for Gamma-Ray and Neutrino Coincidences Using HAWC and ANTARES Data. Astrophys. J., 944(2), 166–9pp.
Abstract: In the quest for high-energy neutrino sources, the Astrophysical Multimessenger Observatory Network has implemented a new search by combining data from the High Altitude Water Cherenkov (HAWC) Observatory and the Astronomy with a Neutrino Telescope and Abyss environmental RESearch (ANTARES) neutrino telescope. Using the same analysis strategy as in a previous detector combination of HAWC and IceCube data, we perform a search for coincidences in HAWC and ANTARES events that are below the threshold for sending public alerts in each individual detector. Data were collected between 2015 July and 2020 February with a live time of 4.39 yr. Over this time period, three coincident events with an estimated false-alarm rate of <1 coincidence per year were found. This number is consistent with background expectations.
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ANTARES Collaboration(Albert, A. et al), Alves, S., Calvo, D., Carretero, V., Gozzini, R., Hernandez-Rey, J. J., et al. (2023). Search for neutrino counterparts to the gravitational wave sources from LIGO/Virgo O3 run with the ANTARES detector. J. Cosmol. Astropart. Phys., 04(4), 004–19pp.
Abstract: Since 2015 the LIGO and Virgo interferometers have detected gravitational waves from almost one hundred coalescences of compact objects (black holes and neutron stars). This article presents the results of a search performed with data from the ANTARES telescope to identify neutrino counterparts to the gravitational wave sources detected during the third LIGO/Virgo observing run and reported in the catalogues GWTC-2, GWTC-2.1, and GWTC-3. This search is sensitive to all-sky neutrinos of all flavours and of energies > 100 GeV, thanks to the inclusion of both track-like events (mainly induced by v μcharged -current interactions) and shower-like events (induced by other interaction types). Neutrinos are selected if they are detected within +/- 500 s from the GW merger and with a reconstructed direction compatible with its sky localisation. No significant excess is found for any of the 80 analysed GW events, and upper limits on the neutrino emission are derived. Using the information from the GW catalogues and assuming isotropic emission, upper limits on the total energy Etot,v emitted as neutrinos of all flavours and on the ratio fv = Etot,v/EGW between neutrino and GW emissions are also computed. Finally, a stacked analysis of all the 72 binary black hole mergers (respectively the 7 neutron star-black hole merger candidates) has been performed to constrain the typical neutrino emission within this population, leading to the limits: Etot,v < 4.0 x 1053 erg and fv < 0.15 (respectively, Etot,v < 3.2 x 1053 erg and fv < 0.88) for E-2 spectrum and isotropic emission. Other assumptions including softer spectra and non-isotropic scenarios have also been tested.
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