P,T-odd Faraday effect as a tool for observation of CP violation in Standard Model

TL;DR

This paper proposes using the P,T-odd Faraday effect in heavy atom vapors as a novel method to observe CP violation effects predicted by the Standard Model, potentially offering a competitive alternative to existing measurements.

Contribution

It introduces the P,T-odd Faraday effect as a new experimental approach to detect CP violation within the Standard Model using heavy atom vapors and estimates its feasibility.

Findings

Estimated rotation angle could reach 10^{-9} rad with suitable conditions.

The method could compete with current electron spin rotation measurements.

Observations could test CP violation predictions at Standard Model levels.

Abstract

It is proposed to employ the P,T-odd Faraday effect, i.e. rotation of the polarization plane of the light propagating through a medium in presence of the electric field, as a tool for observation of P,T-odd effects caused by CP violation within the Standard Model. For this purpose the vapors of heavy atoms like Tl, Pb, Bi are most suitable. Estimates within the Standard Model show: provided that applied field is about 10^5 V/cm and the optical length can be as large as 70000 km, the rotation angle may reach the value corresponding to the recently observable values (10^{-9} rad). These estimates demonstrate that the P,T-odd Faraday effect observations may effectively compete with the recent measurements of the electron spin rotation in an external electric field, performed with diatomic molecules. These measurements exclude the P,T-odd effects at the level 9 orders of magnitude higher than the predictions of the Standard Model.