Neutrino oscillation phenomenology in the SME: A study of the Puma and Puma extended models at DUNE
In the standard model of elementary particles, know as the most accurate theory in history, neutrinos are weakly interacting particles with no mass, however one phenomenon, known as "oscillation of neutrinos", is very well evidenced experimentally which puts two theories that have a large number of experimental tests in check. As a way of trying to explain the physics of neutrinos, and other topics that are still open in particle physics, researchers are carrying out theories called "Beyond the Standard Model". This topic is growing and is gaining a strong presence in recent scientific discussions.
This master thesis investigates the behavior of neutrinos in the so-called Extended Standard Model (SME), an effective field theory that contains the standard model, general relativity, and Lorentz symmetry breaking. Assuming that the effects of oscillation of neutrinos could be a window to the violation of CPT, and consequently a violation of Lorentz symmetry, we sought to understand the phenomenology of neutrinos in the SME through models such as the Bicycle, the BMW and the Puma models, giving special attention to the last one. The Puma model is characterized by two properties: Isotropic Lorentz violation and a zero eigenvalue. This leads to an unconventional dependence of the oscillation on the energy of the neutrino. Initially, this model was used to try to explain the experimental data in various contexts, from nuclear reactors to accelerators.
As a way to improve the Puma model, we studied a perturbation that might better explain the current data. We intend in the near future to determine the parameters of the extended Puma model, in order to explain the experimental data and delimit the parameters compatible with a possible violation of CPT.