# Experimental limit on an exotic parity-odd spin- and velocity-dependent interaction using an optically polarized vapor

## TL;DR

This study uses a highly sensitive atomic magnetometer to set a new, significantly improved experimental limit on a hypothetical exotic parity-odd spin- and velocity-dependent interaction between electrons and nucleons, relevant to physics beyond the Standard Model.

## Contribution

It introduces a novel experimental approach employing an optically polarized vapor magnetometer to constrain exotic electron-nucleon interactions with unprecedented sensitivity.

## Key findings

- Set a new limit on the electron-nucleon coupling $g_A^e g_V^N$ below $10^{-30}$
- Improved the previous experimental limits by up to 17 orders of magnitude
- Provided constraints for mediator boson masses below $10^{-4}$ eV

## Abstract

Exotic spin-dependent interactions between fermions have recently attracted attention in relation to theories beyond the Standard Model. The exotic interactions can be mediated by hypothetical fundamental bosons which may explain several unsolved mysteries in physics. Here we expand this area of research by probing an exotic parity-odd spin- and velocity-dependent interaction between the axial-vector electron coupling and the vector nucleon coupling for polarized electrons. This experiment utilizes a high-sensitivity atomic magnetometer, based on an optically polarized vapor that is a source of polarized electrons, and a solid-state mass containing unpolarized nucleons. The atomic magnetometer can detect an effective magnetic field induced by the exotic interaction between unpolarized nucleons and polarized electrons. We set an experimental limit on the electron-nucleon coupling $g_\text{A}^\text{e} g_\text{V}^\text{N}<$ $10^{-30}$ at the mediator boson mass below $10^{-4}$ eV, significantly improving the current limit by up to 17 orders of magnitude.