Testing general relativity on accelerators

TL;DR

This paper proposes experiments using high-energy accelerators to test the effects of gravity on relativistic massive particles, aiming to confirm general relativity's predictions in a new regime.

Contribution

It introduces a novel experimental approach to measure gravitational effects on relativistic particles using laser Compton scattering at accelerators.

Findings

Confirmed general relativity predictions for ultrarelativistic electrons at current resolution.

Demonstrated high sensitivity of laser Compton scattering to gravitational effects.

Proposed future experiments at advanced accelerators for high-precision tests.

Abstract

Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyze experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable -- maximal energy of the scattered photons -- would experience a significant shift in the ambient gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of resolution and expect our work to be a starting point of further high-precision studies on current and future accelerators, such as PETRA, European XFEL and ILC.