Aspects of Neutrino Oscillation in Alternative Gravity Theories

TL;DR

This paper investigates neutrino spin and flavor oscillations in various curved spacetime backgrounds, deriving general formulas and applying them to constrain parameters of alternative gravity theories using solar neutrino data.

Contribution

It provides a comprehensive analysis of neutrino oscillations in static spherically symmetric spacetimes and derives bounds on alternative gravity theories from neutrino oscillation data.

Findings

Spin oscillation frequency vanishes in high energy limit for circular orbits.

Bounds on parameters of Gauss-Bonnet and f(R) gravity theories are derived from neutrino data.

General formulas for neutrino flavor oscillation phase in curved spacetime are established.

Abstract

Neutrino spin and flavour oscillation in curved spacetime have been studied for the most general static spherically symmetric configuration. Using the symmetry properties we have derived spin oscillation frequency for neutrino moving along a geodesic or in a circular orbit. Starting from the expression of neutrino spin oscillation frequency we have shown that even in this general context, in high energy limit the spin oscillation frequency for neutrino moving along circular orbit vanishes. This finally lends itself to non-zero probability of neutrino helicity flip. While for neutrino flavour oscillation we have derived general results for oscillation phase, which subsequently have been applied to different gravity theories. These include dilaton field coupled to Maxwell field tensor, generalization of Schwarzschild solution by introduction of quadratic curvature terms of all possible form to the Einstein-Hilbert action and finally regular black hole solutions. In all these cases using the solar neutrino oscillation data we can put bounds on the parameters of these gravity theories. While for spin oscillation probability, we have considered two cases, Gauss-Bonnet term added to the Einstein-Hilbert action and the f(R) gravity theory. In both these cases we could impose bounds on the parameters which are consistent with previous considerations. Implications are also discussed.