Eur. Phys. J. C

**19**, 553-560

DOI: 10.1007/s100520100599

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

##### 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 (
). 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
are inferred for a rotating observer
(with vanishing linear acceleration) comoving with the earth,
hence
rad/sec, and all other
alternative mechanisms generating the oscillation phenomena have
been neglected. In this case we find that the constraints on
are given by
for solar
neutrinos and
for atmospheric neutrinos.

**©**

*Società Italiana di Fisica, Springer-Verlag 2001*