Neutrino Oscillations in Particle Physics and Astrophysics

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física Teórica. Fecha de lectura: 29-06-2018Neutrinos are described in the Standard Model (SM) by three left-handed fermion elds, one for each fermion generation. In the SM, the masses of the fermions arises as a Yukawa interaction between the right-handed and the left-handed fermion elds, and the Higgs doublet. Because of the lack of a right-handed eld for neutrinos, these fermions are massless within the SM. Experiments measuring the avor composition of neutrinos have stablished the oscillation of the avor along its path. This oscillation can be explained in the scenario of a mixing between neutrino avor and neutrino mass states. This thesis is devoted to the study of the neutrino avor oscillations within di erent mixing models. In particular, it is focused into the physics reach by the new generation of neutrino telescopes, like IceCube and DeepCore. The low energy part of the atmospheric neutrino ux measured by DeepCore lead a sizable avor oscillation in the muon disappearance channel ( ! ). By combining the latest experimental data collected by this detector (up to 2016) with the results of other oscillation experiments, we have performed a global ts within the three-neutrino mixing framework. In this work has been also discussed the complementarity role played by atmospheric/accelerator and the reactor data on the determination of the atmospheric mass parameter. IceCube can be also considered as a tool to look for New Physics signals. The minimal extension of the SM to explain the neutrino masses consist of a heavy right-handed neutrino eld. The mass of this new fermion is not predicted by any model, it can take any value over a wide range of orders of magnitude. For masses around GeV, we have studied in a di erent work the detection of the new fermion by looking for \Double-Cascades" events topologies. We have considered two di erent scenarios where the signal can be created by a heavy neutrino, the mixing of the heavy state with a light neutrino through a NC, and the production of the heavy state via a transition magnetic moment. The results indicate that IceCube improve the current bounds in the scenarios considered for heavy states with masses around 1 GeV. Another New Physics scenario considered is the so-called Quantum Decoherence, which introduces a damping e ect on the avor oscillation. In a recent work, we have developed a new formalism to study this e ect through non-adiabatic matter. By a t of the atmospheric events measured by IceCube and DeepCore, it is shown that these experiments improve over the current bound from other experiments. The primary goal of IceCube is the detection of astrophysical neutrinos, what happened in 2013. This energetic events opens the possibility to study New Physics on them. In another, work we have considered the impact of Non-Standard Interactions on the avor of this events, nding large deviations from the three-neutrino mixing prediction. Neutrino physics is moving into the precission era, but still a lot of fundamental and exciting problems remain without answer. This converts to this reach area in a very promising eld for the near futur