Vacuum Cherenkov Radiation In Quantum Electrodynamics With High-Energy Lorentz Violation

TL;DR

This paper investigates vacuum Cherenkov radiation within a Lorentz-violating extension of the Standard Model, analyzing energy thresholds, experimental bounds, and implications for high-energy cosmic rays, suggesting Lorentz violation could occur below the Planck scale.

Contribution

It introduces a renormalizable, CPT-invariant Lorentz-violating model predicting vacuum Cherenkov radiation, including neutral particles, and compares theoretical predictions with experimental data.

Findings

Energy threshold for Cherenkov radiation can be lowered by composite particle effects.

Lorentz violation scale Lambda_L could be as low as 10^{14}-10^{15} GeV.

Model predicts Cherenkov radiation of neutral particles.

Abstract

We study phenomena predicted by a renormalizable, CPT invariant extension of the Standard Model that contains higher-dimensional operators and violates Lorentz symmetry explicitly at energies greater than some scale Lambda_{L}. In particular, we consider the Cherenkov radiation in vacuo. In a rather general class of dispersion relations, there exists an energy threshold above which radiation is emitted. The threshold is enhanced in composite particles by a sort of kinematic screening mechanism. We study the energy loss and compare the predictions of our model with known experimental bounds on Lorentz violating parameters and observations of ultrahigh-energy cosmic rays. We argue that the scale of Lorentz violation Lambda_{L} (with preserved CPT invariance) can be smaller than the Planck scale, actually as small as 10^{14}-10^{15} GeV. Our model also predicts the Cherenkov radiation of neutral particles.