$\mathcal{P}$, $\mathcal{T}$-odd Faraday rotation in intracavity absorption spectroscopy with molecular beam as a possible way to improve the sensitivity of the search for the time reflection noninvariant effects in nature

TL;DR

This paper proposes a cavity-enhanced polarimetric method using molecular beams to detect $ ext{P}$, $ ext{T}$-odd Faraday rotation, potentially improving constraints on the electron electric dipole moment by several orders of magnitude.

Contribution

It introduces a novel experimental scheme combining intracavity absorption spectroscopy with molecular beams to enhance sensitivity to $ ext{P}$, $ ext{T}$-odd effects, offering an alternative to existing methods.

Findings

Theoretical simulation indicates potential for significant sensitivity improvement.

The method could improve current constraints on the electron EDM.

Use of PbF and ThO molecular beams is promising for this approach.

Abstract

The present constraint on the space parity ($\mathcal{P}$) and time reflection invariance ($\mathcal{T}$) violating electron electric dipole moment ($e$EDM) is based on the observation of the electron spin precession in an external electric field using the ThO molecule. We propose an alternative approach: observation of the $\mathcal{P}$,~$\mathcal{T}$-odd Faraday effect in an external electric field using the cavity-enhanced polarimetric scheme in combination with a molecular beam crossing the cavity. Our theoretical simulation of the proposed experiment with the PbF and ThO molecular beams shows that the present constraint on the $e$EDM in principle can be improved by a few orders of magnitude.