CP-Violation in Low-Energy Photon-Photon Interactions

TL;DR

This paper explores how CP-violation could affect photon-photon interactions and vacuum birefringence, proposing observable signatures in experiments like PVLAS-Phase II, and estimates the effect within the Standard Model using chiral perturbation theory.

Contribution

It introduces the idea that CP-violation in photon interactions can produce detectable Fourier components in vacuum birefringence experiments and calculates the effect within the Standard Model.

Findings

CP-violation induces characteristic Fourier components in outgoing wave spectra.

The magnitude of the effect is estimated using chiral perturbation theory.

Potential implications for detecting CP-violation in photon interactions.

Abstract

CP-violation in the loop-mediated photon-photon interactions would modify the birefringence of the quantum vacuum. We discuss the implications of this effect on the PVLAS-Phase II experiment, in which a time-dependent magnetic field is modulated. We show that the violation of CP would imply the existence of characteristic Fourier components, in the intensity spectrum of the outgoing wave. In order to estimate the magnitude of this effect within the Standard Model, we use chiral perturbation theory to compute the theta-term contribution to the coefficient of the leading CP-odd vertex, in the low-energy effective field theory for photon dynamics.