Fundamental constants from photon-photon scattering in three-beam collisions

TL;DR

This paper proposes a three-beam laser collision setup to measure fundamental quantum electrodynamics constants more effectively, enabling detection of photon scattering and vacuum birefringence with current technology.

Contribution

It introduces a novel three-beam collision configuration that improves measurement sensitivity and separates scattering contributions, advancing experimental QED studies.

Findings

Higher signal-to-noise ratio in three-beam collisions

Separation of different photon scattering orders

Feasibility with current laser technology

Abstract

Direct measurement of the elastic scattering of real photons on an electromagnetic field would allow the fundamental low-energy constants of quantum electrodynamics (QED) to be experimentally determined. We show that scenarios involving the collision of three laser beams have several advantages over conventional two-beam scenarios. The kinematics of a three-beam collision allows for a higher signal-to-noise ratio in the detection region, without the need for polarimetry and separates out contributions from different orders of photon scattering. A planar configuration of colliding a photon beam from an x-ray free electron laser with two optical beams is studied in detail. We show that measurements of elastic photon scattering and vacuum birefringence are possible with currently available technology.