Price for environmental neutrino-superluminality

Abstract

Abstract:We ask whether the recent OPERA results on neutrino superluminality could be an environmental effect characteristic of the local neighborhood of our planet, without the need of violation of the Poincaré-invariance at a fundamental level. We show, that model-indepenently, such a possibility implies the existence of new gravitational degrees of freedom. Namely, this explanation requires the existence of a new spin-2 field of a planetary Compton wave-length that is coupled to neutrinos and the rest of the matter asymmetrically, both in the magnitude and in the sign. Sourced by the earth this field creates an effective metric on which neutrinos propagate superluminally, whereas other species are much less sensitive to the background. Such a setup, at an effective field theory level, passes all immediate phenomenological tests, but at the expense of sacrificing calculability for some of the phenomena that are under perturbative control in ordinary gravity. The natural prediction is an inevitable appearance of a testable long-range gravitytype fifth force. Despite phenomenological viability, the sign asymmetry of the coupling we identify as the main potential obstacle for a consistent UV-completion. We also discuss the possible identification of this field with a Kaluza-Klein state of an extra dimension in which neutrino can propagate.

Constraints from orbital motions around the Earth of the environmental fifth-force hypothesis for the OPERA superluminal neutrino phenomenology

“…For earlier studies on superluminal motions of neutrinos in various frameworks, see, e.g., [10,11,12,13,14,15,16]. Dvali and Vikman [17] wondered if the OPERA superluminal phenomenology could be an environmental effect characteristic of the local neighborhood of the Earth, without the need of violation of the Poincaré invariance at a fundamental level. Such a scenario, at an effective field theory level, yields naturally an inevitable appearance of a testable long-range fifth force of gravitational type.…”

“…= c 5 8πG = 2.43 × 10 18 GeV is the energy equivalent of the reduced Planck's mass, where is the reduced Planck constant, c is the speed of light in vacuum and G is the Newtonian constant of gravitation, and the scale M * sets the strength of the coupling of the putative new massive spin-2 degree of freedom to the neutrino [17]. For other investigations involving various aspects of gravitation, astrophysics and cosmology, see, e.g., [19,20,21,22,23,24,25,26,27,28,29,30,31].…”

“…We will perform a first-order perturbative calculation without making any a-priori assumptions either on the size of λ or on the trajectory's configuration of the test particle orbiting the central body acting as source of the putative exotic effect. We will also put constraints on the strength parameter α for various values of λ within the ranges envisaged by Dvali and Vikman [17] in view of the latest results from the orbital determination of some natural and artificial bodies around the Earth. Thus, it will be possible to infer lower bounds on the coupling of neutrino to the new hypothetical force, which is given by M P /M * [17].…”

Lorentz violation, gravity, dissipation and holography

“…From the consistent models proposed, most attempted to accommodate the result by parametrizing appropriately the neutrino couplings in the SM. The two extra alternatives proposed included a new massive graviton interaction, [86] and a new scalar interaction [87].…”

Lorentz invariance violation in modified gravity

“…This is achieved thanks to screening features such as the Vainshtein mechanism for theories with higher order derivative self interactions [2], or the chameleon [3], symmetron [4] or Damour-Polyakov properties [5] for theories with non-linear effective potentials in the presence of pressure-less matter. Recently and after the claim of super-luminal propagation of neutrinos by the OPERA experiment [6], it has been suggested that fermions may travel faster than the speed of light in dense environments where the presence of matter offers a breaking of Lorentz invariance [7]. This was further pursued in [8][9][10] and then in [11] where Galileons were used to describe the OPERA claims although failing to respect the tight bounds on the deviation of the electron speed from the speed of light.…”