Neutrino oscillations in non-inertial frames and the violation of the equivalence principle

G. Lambiase

doi:doi:10.1007/s100520100599

2022 Impact factor 4.4

Particles and Fields

Eur. Phys. J. C 19, 553-560
DOI: 10.1007/s100520100599

Neutrino mixing induced by the equivalence principle violation

G. Lambiase^{1, 2}

¹ Dipartimento di Scienze Fisiche "E. R. Caianiello", Università di Salerno, 84081 Baronissi (SA) Italy
² Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Italy

lambiase@sa.infn.it

(Received: 14 December 2000 / Published online: 15 March 2001 -© Springer-Verlag 2001)

Abstract
Neutrino oscillations are analyzed in an accelerating and rotating reference frame, assuming that the gravitational coupling of neutrinos is flavor dependent, which implies a violation of the equivalence principle. Unlike the usual studies in which a constant gravitational field is considered, such frames could represent a more suitable framework for testing if a breakdown of the equivalence principle occurs, due to the possibility to modulate the (simulated) gravitational field. The violation of the equivalence principle implies, for the case of a maximal gravitational mixing angle, the presence of an off-diagonal term in the mass matrix. The consequences on the evolution of flavor (mass) eigenstates of such a term are analyzed for solar (oscillations in the vacuum) and atmospheric neutrinos. We calculate the flavor oscillation probability in the non-inertial frame, which does depend on its angular velocity and linear acceleration, as well as on the energy of neutrinos, the mass-squared difference between two mass eigenstates, and on the measure of the degree of violation of the equivalence principle ( $\Delta\gamma$ ). In particular, we find that the energy dependence disappears for vanishing mass-squared difference, unlike the result obtained by Gasperini, Halprin, Leung, and other physical mechanisms proposed as a viable explanation of neutrino oscillations. Estimations on the upper values of $\Delta\gamma$ are inferred for a rotating observer (with vanishing linear acceleration) comoving with the earth, hence $\omega \sim 7\cdot 10^{-5}$ rad/sec, and all other alternative mechanisms generating the oscillation phenomena have been neglected. In this case we find that the constraints on $\Delta\gamma$ are given by $\Delta\gamma\leq 10^2$ for solar neutrinos and $\Delta\gamma\leq 10^6$ for atmospheric neutrinos.