Dark Matter and Solar Atmospheric Neutrino Searches with the KM3NeT-ORCA and ANTARES Neutrino Telescopes

Abstract

The ANTARES neutrino telescope and its successor, KM3NeT, located in the sea bed of the Mediterranean, have been designed to study neutrinos from a variety of sources over a wide energy range. Both neutrino telescopes have a very broad scientific scope: the measurement of the diffuse flux of cosmic neutrinos, unveiling the origin of cosmic-rays, the study of point–like astrophysical sources of neutrinos or the discovery of the mysterious nature of dark matter. This thesis collects the results of two different but related researches. On the one hand, 11 years of ANTARES data have been analyzed to perform a search for Solar Atmospheric neutrino (SAνs). The study and understanding of SAνs is crucial at different levels. First, the detection of SAνs can give indirect information about the primary cosmic-ray composition, the propagation of charged particles in the solar medium and, consequently, help the scientific community to understand the density and chemical structure of the Sun. Second, these neutrinos could be used as a standard neutrino flux for detector calibration. Last but not least, SAνs represent an unavoidable background for dark matter searches. On the other hand, the performance of the KM3NeT-ORCA detector to perform dark matter searches towards the Sun is studied. ORCA is the low energy component of KM3NeT, optimized for the study of neutrinos created by cosmic–rays in the Earth’s atmospere. In this thesis, dark matter is assumed to be made ofWeakly Interactive Massive Particles (WIMPs) that accumulate in celestial bodies. The privileged proximity of the Sun to the Earth makes it a perfect candidate to perform indirect dark matter searches. The Monte Carlo simulation framework in both detectors (ANTARES and KM3NeT), which includes the simulation of neutrino interactions, particle generation and light propagation, event selection and reconstruction, as well as the statistical treatment of data and systematic uncertainties have been described in great detail. The search of SAνs with 11 years of ANTARES data, based in a likelihood method, gives no evidence for a solar atmospheric neutrino signal above the expected background. An upper limit at 90% confidence level on the flux of solar atmospheric neutrinos is obtained to be equal to 7×10−11 [TeV−1cm−2s−1] at Eν = 1 TeV for the reference model assumed. In the second part of the thesis, the discovery potential of the ORCA detector is evaluated. Our results show that ORCA is potentially competitive in the search for dark matter in the Sun, surpassing the previous results from the ANTARES and SK searches, and being close to the IceCube results.