My research focuses on theoretical studies of possible violations of spacetime symmetries through the implementation of techniques to search for deviations from these symmetries in astroparticle physics.

Cosmic rays
Earth's atmosphere is continuously bombarded by energetic particles. Mostly compossed by high-energy protons, these cosmic rays can be used to search for minute deviations from exact Lorentz invariance, which can produce several unconventional effects. For instance, modifications of Maxwell electrodynamics can make high-energy protons emit photons in vacuum                                $$ \color{blue}{\pmb{p}} \to \color{blue}{\pmb{p}} +\color{red}{\pmb{\gamma}} $$ This emission of vacuum Cherenkov radiation occurs only above a threshold energy, at which protons would rapidly lose energy. Therefore, the observation of high-energy protons in cosmic-ray observatories allows contraining this type of violations of Lorentz symmetry.

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Gamma-ray astronomy
High-energy photons produced by violent astrophysical processes hit the atmosphere triggering showers of particles than can be observed using Cherenkov telescopes. These instruments can serve as sensitive probes of Lorentz invariance by searching for a variety of phenomena. For instance, photons can move at different speeds depending on their energy. This effect would produce a dispersion of photons emitted by a transcient source, so that a relative time delay would be observed between high- and low-energy photons.
Other types of effects that can be studied in gamma-ray telescopes include uncoventional reactions of high-energy photons with the atmosphere.

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Astrophysical neutrinos
High-energy neutrinos are also sensitive probes of Lorentz invariance, in particular to a subset of coefficients controlling Lorenz violation that are inaccesible in neutrino-oscillation experiments. These oscillation-free effects modify the behavior of the three neutrino flavors in the same form; hence, the only way to search for these effects is in kinematical measurements and nuclear reactions, in which the modified energy-momentum relations of the neutrinos introduce unconventional effects.

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My interests also include searches for violations of Lorentz and CPT invariance in neutrino-oscillation experiments and low-energy nuclear processes involving neutrinos. Things I have been working on include:

Tests of Lorentz invariance using beta decays
Tests of Lorentz invariance using neutrino oscillations
Alternative models for neutrino oscillations

See also:
Review (brief introduction to violations of Lorentz invariance and neutrinos)