Neutrino oscillations in extended theories of gravity

Abstract

We analyze neutrino mixing and oscillations within the framework of extended theories of gravity. In particular, by relying on the covariant reformulation of Pontecorvo's formalism, we evaluate the oscillation probability of neutrinos propagating in several static spacetimes described by gravitational actions quadratic in the curvature invariants. We show that neutrino oscillation phase is sensitive to the violation of the strong equivalence principle. This connection may be in principle explained via the appearance of the Eddington-Robertson-Schiff parameter in the neutrino Hamiltonian. The above studies are then specialized to different extended models in order both to quantify such a violation and to understand how the characteristic free parameters of the theories could affect the standard result. The possibility to fix new bounds on such parameters and to constrain extended theories of gravity is also discussed.

Neutrino Oscillations and Lorentz Invariance Violation

“…In fact, it can open another window on the study of fundamental symmetries of nature, presenting another sector where posing Lorentz Invariance under investigation. Finally, neutrino oscillation physics can be used in the future to investigate the validity of alternative gravity theories, i.e., modified General Relativity theories [99,100]. These models indeed introduce a modification of the geometry of space-time, causing kinematical perturbations that can manifest in neutrino oscillation sector.…”

Revealing neutrino nature and CPT violation with decoherence effects

“…Before concluding let us emphasize that a detection of C PT violation induced by decoherence effects could be attributed to fluctuations of the space-time [30][31][32][33][34][35][36], thus representing a signature of quantum gravity. Moreover, the studies on neutrino mixing in curved space [51][52][53][54] could be also generalized by including in them the decoherence and dissipation effects here presented. Therefore, our study might open new windows of opportunity to address several open questions in fundamental physics.…”

On the very nature of neutrinos: the $\beta$-decay as a test bench

“…Finally, we emphasize that the present formalism might be of some relevance for a deeper understanding of how gravity influences decay processes and neutrino oscillations [21,22,23,24,25,26,27]. Although a more rigorous curved-spacetime calculation is required to address these situations, the present study may provide a good approximation in the case of moderate gravitational field, for which one can naively treat the decaying particle as being accelerated in flat spacetime.…”