# Precision tests of QED and non-standard models by searching photon-photon scattering in vacuum with high power lasers

## TL;DR

This paper proposes experimental setups using high-power lasers to detect photon-photon scattering in vacuum, aiming to test Quantum Electrodynamics and constrain non-standard models with unprecedented sensitivity.

## Contribution

It introduces a comprehensive method to measure phase shifts caused by photon interactions, enabling tests of QED and new physics at petawatt laser facilities.

## Key findings

- Designed experiments to detect photon-photon scattering at HERCULES.
- Projected sensitivity surpassing current constraints, potentially detecting QED effects.
- Suggested improvements for future exawatt facilities like ELI.

## Abstract

We study how to search for photon-photon scattering in vacuum at present petawatt laser facilities such as HERCULES, and test Quantum Electrodynamics and non-standard models like Born-Infeld theory or scenarios involving minicharged particles or axion-like bosons. First, we compute the phase shift that is produced when an ultra-intense laser beam crosses a low power beam, in the case of arbitrary polarisations. This result is then used in order to design a complete test of all the parameters appearing in the low energy effective photonic Lagrangian. In fact, we propose a set of experiments that can be performed at HERCULES, eventually allowing either to detect photon-photon scattering as due to new physics, or to set new limits on the relevant parameters, improving by several orders of magnitude the current constraints obtained recently by PVLAS collaboration. We also describe a multi-cross optical mechanism that can further enhance the sensitivity, enabling HERCULES to detect photon-photon scattering even at a rate as small as that predicted by QED. Finally, we discuss how these results can be improved at future exawatt facilities such as ELI, thus providing a new class of precision tests of the Standard Model and beyond.