Possible Observation of Photon Speed Energy Dependence

TL;DR

This paper investigates the possibility that photon speed varies with energy, using experimental data from high-energy scattering and polarimeters, suggesting photons at 12.7 GeV may travel faster than light.

Contribution

It introduces a novel approach to test photon speed energy dependence through high-energy scattering data and analyzes existing experimental results for potential superluminal photon behavior.

Findings

Evidence of photons at 12.7 GeV possibly exceeding light speed by 5.1 mm/s

An asymmetry spectrum indicates a much smaller effect, but with less certainty

Highlights the sensitivity of high-energy experiments to photon velocity variations

Abstract

Current constraints on photon velocity variability are summarized and displayed in terms of an energy dependent vacuum refraction index. It is shown that the energy-momentum balance of high energy Compton scattering is very sensitive to the outgoing photon speed. A missing energy observation in HERA Compton polarimeter data indicates that photons with 12.7 GeV energy are moving faster than light by 5.1(1.4)mm/s. An asymmetry spectrum measured by the SLC longitudinal polarimeter implies however an effect which is 42 times smaller, although the interpretation of the data is less clear here.