An attempt to study axion-photon coupling using compact binary systems with high Shapiro time delay

TL;DR

This paper investigates axion-photon conversion in pulsar binary systems with high Shapiro delay to explore potential constraints on axion-like particles, analyzing specific systems and discussing the method's feasibility and limitations.

Contribution

It introduces a novel approach using high Shapiro delay binary systems to constrain axion-photon coupling, including detailed modeling and numerical analysis.

Findings

Upper limits weaker than existing constraints

Method offers higher reliability despite weaker bounds

Potential for improved constraints with future observations

Abstract

We study the axion-photon conversion process in pulsar binary systems with high Shapiro time delay. In these binary systems, the orbital plane is nearly parallel to the line of sight. When the companion star is positioned between the pulsar and the Earth, the pulsar radiation beam will pass through the companion's magnetic field, potentially leading to axion-photon conversion that affects the intensity and linear polarization of the photons. The advantage of using such systems for axion or axion-like particle (ALP) research is that the intrinsic intensity and polarization state of the source photons can be well determined. This work analyzes the axion-photon conversion and the magnetic field along the photon path, establishing the corresponding model and solving it numerically. We choose PSR J1614-2230 and PSR J1910-5959A for our study. By assuming the companion's magnetic field, magnetic axis angle, and detector sensitivity, we discuss the feasibility of using high Shapiro delay binary systems to constrain the axion/ALP parameter space. We find that the upper limits derived from these two sources are weaker then existing constraints. However, considering the higher reliability, the method proposed in this work is still valuable. As more suitable samples and richer observational results are discovered, further constraints on the axion parameters could be strengthened.