Neutrino Oscillations, Lorentz/CPT Violation, and Dark Energy

TL;DR

This paper explores how dark energy coupling to neutrinos could cause Lorentz and CPT violations in neutrino oscillations, proposing methods to detect such effects through high-energy neutrino observations and directional dependence analysis.

Contribution

It introduces a specific form of DE-induced Lorentz/CPT violation in neutrino oscillations and suggests experimental approaches to detect these effects with unprecedented sensitivity.

Findings

Ultra-high-energy neutrinos can improve sensitivity to Lorentz/CPT violation by seven orders of magnitude.

Directional dependence of neutrino oscillations relative to the CMB frame is a potential signature.

Current and future neutrino experiments can test for DE-neutrino coupling effects.

Abstract

If dark energy (DE) couples to neutrinos, then there may be apparent violations of Lorentz/CPT invariance in neutrino oscillations. The DE-induced Lorentz/CPT violation takes a specific form that introduces neutrino oscillations that are energy independent, differ for particles and antiparticles, and can lead to novel effects for neutrinos propagating through matter. We show that ultra-high-energy neutrinos may provide one avenue to seek this type of Lorentz/CPT violation in \nu_\mu-\nu_\tau oscillations, improving the current sensitivity to such effects by seven orders of magnitude. Lorentz/CPT violation in electron-neutrino oscillations may be probed with the zenith-angle dependence for high-energy atmospheric neutrinos. The ``smoking gun,'' for DE-neutrino coupling would, however, be a dependence of neutrino oscillations on the direction of the neutrino momentum relative to our peculiar velocity with respect to the CMB rest frame. While the amplitude of this directional dependence is expected to be small, it may nevertheless be worth seeking in current data and may be a target for future neutrino experiments.