# On the validity of constraints on light elementary particles and extra-dimensional physics from the Casimir effect

## TL;DR

This paper re-evaluates constraints on light elementary particles and extra-dimensional physics from the Casimir effect, demonstrating that the proximity force approximation remains valid for Yukawa interaction calculations.

## Contribution

It provides an exact calculation of Yukawa interaction constraints in the sphere-plate setup, confirming the validity of the proximity force approximation.

## Key findings

- Exact and PFA-based calculations yield identical constraints.
- Incorrect claims about PFA's inapplicability are clarified.
- Constraints on Yukawa interactions are reaffirmed.

## Abstract

We discuss the constraints on the parameters of a Yukawa interaction obtained from the indirect measurements of the Casimir pressure between parallel plates using the sphere-plate configuration. Recently, it was claimed in the literature that the application of the proximity force approximation (PFA) to the calculation of a Yukawa interaction in the sphere-plate configuration could lead to a large error of order 100\% in the constraints obtained. Here we re-calculate the constraints both exactly and using the PFA, and arrive at identical results. We elucidate the reasons why an incorrect conclusion was obtained suggesting that the PFA is inapplicable to calculate the Yukawa force.