# Constraints on axion-like particles and non-Newtonian gravity from measuring the difference of Casimir forces

## TL;DR

This paper uses Casimir force measurements to set new, stronger constraints on axion-like particles and non-Newtonian gravity over a broad range of interaction parameters, improving upon previous experimental limits.

## Contribution

It provides the most stringent experimental constraints to date on axion-like particles and non-Newtonian gravity within specified ranges, using Casimir force difference measurements.

## Key findings

- Constraints on axion-nucleon coupling are up to 14.6 times stronger.
- Constraints on non-Newtonian gravity are up to 177 times stronger.
- Results cover axion masses from 2.61 meV to 0.9 eV and interaction ranges from 30 nm to 5.4 μm.

## Abstract

We derive constraints on the coupling constants of axion-like particles to nucleons and on the Yukawa-type corrections to Newton's gravitational law from the results of recent experiment on measuring the difference of Casimir forces between a Ni-coated sphere and Au and Ni sectors of a structured disc. Over the wide range of axion masses from 2.61\,meV to 0.9\,eV the obtained constraints on the axion-to-nucleon coupling are up to a factor of 14.6 stronger than all previously known constraints following from experiments on measuring the Casimir interaction. The constraints on non-Newtonian gravity found here are also stronger than all that following from the Casimir and Cavendish-type experiments over the interaction range from 30\,nm to $5.4\,\mu$m. They are up to a factor of 177 stronger than the constraints derived recently from measuring the difference of lateral forces. Our constraints confirm previous somewhat stronger limits obtained from the isoelectronic experiment, where the contribution of the Casimir force was nullified.