Bounds on the Coupling of Light Pseudoscalars to Nucleons from Optical Laser Experiments

TL;DR

This paper establishes improved laboratory bounds on the coupling constants of light pseudoscalars to protons and neutrons using optical laser experiments, refining previous limits and implications for particle physics.

Contribution

The study provides new, tighter laboratory bounds on pseudoscalar-nucleon couplings by linking laser experiment results to particle interaction limits, enhancing constraints on light pseudoscalars.

Findings

Bound on proton coupling: $g_p^2/4 ext{π} < 1.7 imes 10^{-9}$

Bound on neutron coupling: $g_n^2/4 ext{π} < 6.8 imes 10^{-8}$

Laser experiments constrain pseudoscalar interactions with nucleons.

Abstract

We find the following improved laboratory bounds on the coupling of light pseudoscalars to protons and neutrons: $g_p^2/4\pi < 1.7 \times 10^{-9}$ and $g_n^2/4\pi < 6.8 \times 10^{-8}$. The limit on $g_p$ arises since a nonzero $g_p$ would induce a coupling of the pseudoscalar to two photons, which is limited by experiments studying laser beam propagation in magnetic fields. Combining our bound on $g_p$ with a recent analysis of Fischbach and Krause on two-pseudoscalar exchange potentials and experiments testing the equivalence principle, we obtain our limit on $g_n$. (PACS number(s): 14.20.Dh/14.80.-j/12.20.Fv/04.90.+e)