First Constraint on Axion-Photon Coupling g_γ from Neutron Star Observations

2025/06/09 by Jun-Chen Wang, Shunshun Cao, Wang, Jun-Chen +9
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #High Energy Physics - Phenomenology (hep-ph) #Pulsars and Gravitational Waves Research

paper · pdf · doi:10.48550/arxiv.2506.07546

openalex publication_date 2025/06/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31

Abstract

We propose a novel method to detect axions which uniquely depends on the dimensionless axion-photon coupling g_γ, independent of the suppressive axion decay constant f_a. Using neutron star PSR B1919+21 data from the Five-hundred-meter Aperture Spherical Telescope, we derive the first constraint |g_γ|<0.93 at 1σ confidence level for ultra-light axions (m_a < 10^-11 eV).

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