On the Possibility of Superluminal Neutrino Propagation

TL;DR

This paper investigates the theoretical possibility of neutrinos traveling faster than light, examines constraints from astrophysical data, and proposes Lorentz-violating models that could explain superluminal neutrino propagation.

Contribution

It introduces two novel Lorentz-violating models for superluminal neutrinos and analyzes their compatibility with existing astrophysical constraints.

Findings

SN1987a data rules out certain superluminal models

Proposes models where superluminality depends on energy and direction

Background fields could reconcile OPERA results with astrophysical constraints

Abstract

We analyze the possibility of superluminal neutrino propagation delta v = (v - c)/c > 0 as indicated by OPERA data, in view of previous phenomenological constraints from supernova SN1987a and gravitational Cerenkov radiation. We argue that the SN1987a data rule out delta v ~ (E_\nu/M_N)^N for N \le 2 and exclude, in particular, a Lorentz-invariant interpretation in terms of a 'conventional' tachyonic neutrino. We present two toy Lorentz-violating theoretical models, one a Lifshitz-type fermion model with superluminality depending quadratically on energy, and the other a Lorentz-violating modification of a massless Abelian gauge theory with axial-vector couplings to fermions. In the presence of an appropriate background field, fermions may propagate superluminally or subluminally, depending inversely on energy, and on direction. Reconciling OPERA with SN1987a would require this background field to depend on location.