Sterile neutrino shortcuts in asymmetrically warped extra dimensions

Abstract

Light sterile neutrinos are a popular extension of the Standard Model and are being discussed as a possible explanation for various neutrino oscillation anomalies, including the LSND, MiniBooNE, Reactor and Gallium anomalies. In order to avoid inconsistencies with constraints derived from disappearance experiments and cosmology, altered dispersion relations -which may originate from extra dimensions -have been proposed as a possible solution, dubbed as "neutrino shortcuts in the extra dimension". In this paper we develop a neutrino mass model with an asymmetrically warped extra dimension and two additional gauge singlet neutrinos, one being responsible for neutrino mass generation, while the other one is allowed to propagate in the extra dimension, giving rise to the desired change of the dispersion relation on the brane. By compactifying the extra-dimensional theory on an S 1 /Z 2 orbifold, deriving the shape of the Kaluza-Klein tower and identifying the effective sterile neutrino dispersion relation on the brane, we can demonstrate that the earlier, phenomenological models are recovered as the 4-dimensional effective field theory limit of the model discussed here.

Neutrino Oscillations and Lorentz Invariance Violation

“…In fact, it can open another window on the study of fundamental symmetries of nature, presenting another sector where posing Lorentz Invariance under investigation. Finally, neutrino oscillation physics can be used in the future to investigate the validity of alternative gravity theories, i.e., modified General Relativity theories [99,100]. These models indeed introduce a modification of the geometry of space-time, causing kinematical perturbations that can manifest in neutrino oscillation sector.…”

Sterile neutrinos with altered dispersion relations revisited

“…Altered dispersion relations due to effective potentials in the Hamiltonian can lead to energy dependent oscillation parameters. The nature of such an additional potential can be shortcuts through extra dimensions [34,41]. This type of modification, together with the existence of one or more sterile neutrinos, has been suggested as a solution to the anomalies found in neutrino oscillation experiments [27,41].…”

“…The nature of such an additional potential can be shortcuts through extra dimensions [34,41]. This type of modification, together with the existence of one or more sterile neutrinos, has been suggested as a solution to the anomalies found in neutrino oscillation experiments [27,41]. In the 3+1 scenario with modified dispersion relations, the neutrino Hamiltonian in vacuum is given by…”

Sterile neutrinos with altered dispersion relations as an explanation for neutrino anomalies

“…To arrive at this conclusion, we first have pointed out that for 3+1 neutrino models with sterile neutrino altered dispersion relations, the predominantly sterile state decouples at energies far above the resonance, which thus hides the sterile neutrino in accelerator experiments operating at high energies [27,28]. As has been recently pointed out [29], such a scenario results as the effective field theory limit of sterile neutrinos propagating in an asymmetrically warped extra dimension. However, a level crossing occurs at the resonance energy, and the Hamiltonian eigenstates swap their flavor content.…”

“…This running time difference manifests itself as an additional negative potential in the Hamiltonian proportional to the relative time difference δt t =: ε, the so-called shortcut parameter (always entering the Hamiltonian as multiplied by the energy E). Although the semi-classical picture may not be truly accurate, its predictions regarding the form of the potential are correct to leading order in the shortcut parameter [29].…”