Dark matter search and neutrino physics in Liquid Argon

Several astrophysical observations, both on a galactic and cosmological scales, showing that there is a 'missing mass' in the observable Universe, can be explained assuming a non-luminous kind of matter, hence called 'dark matter'. One of the most promising candidates is the Weakly Interacting Massive Particle (WIMP), a non-relativistic massive particle, gravitationally and weakly interacting with baryonic matter. The present work is specifically focused on the physics potential besides WIMP search of dark matter detectors filled with Liquid argon, like DarkSide and DEAP-3600. Liquid argon is an optimal target thanks to its high scintillation and ionization yields. DEAP-3600 is a single-phase detector, exploiting the scintillation channel only, while DarkSide-20k and Argo, future tonne scale experiments from the DarkSide program, are dual-phase Time Projection Chambers (TPCs), looking at both scintillation and ionization signals. The large mass (3.3 tons) of the DEAP-3600 target has allowed me to perform an analysis to search for Multi Interacting Massive Particles (MIMPs), a dark matter candidate alternative to WIMPs, at masses above 10¹⁶ GeV and with argon-dark matter spin-independent cross-section of about 10^-22 cm², fully setting up the upcoming unblinding of three years of data taking. Going from the present to the future dark matter detectors, DarkSide-20k and Argo will be characterized by an extraordinary sensitivity at low energy recoils. This is mainly consequence of the high energy resolution of the chosen photodetectors, Silicon Photomultipliers (SiPMs). Custom SiPMs have been designed for the dark matter search in DarkSide-20k; hence, SiPMs have been here characterized, with a focus on their correlated noises, namely afterpulses and optical cross-talks. The same sensitivity at low energy brings also to a strong potential in detecting supernova neutrinos via coherent elastic neutrino-nucleus scattering (CEvNS) in argon by exploiting the ionization signal. The related sensitivity study is here performed showing that the neutrino emission will be detected for any galactic supernova, with a good accuracy in reconstructing the main parameters of the burst, namely the total energy of neutrinos and their average energy. (author)