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arXiv · 2506.07546

First Constraint on Axion-Photon Coupling $g_{\gamma}$ from Neutron Star Observations

Jun-Chen Wang·Shunshun Cao·Jinchen Jiang·Yandong Liu·Qing-Hong Cao·Lijing Shao
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Abstract

We propose a novel method to detect axions which uniquely depends on the dimensionless axion-photon coupling $g_{\gamma}$, 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 $|g_{\gamma}|<0.93$ at $1\sigma$ confidence level for ultra-light axions ($m_a < 10^{-11}$ eV).

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Jun-Chen Wang, Shunshun Cao, Jinchen Jiang, Yandong Liu, Qing-Hong Cao, Lijing Shao. 2025-06-09. First Constraint on Axion-Photon Coupling $g_{\gamma}$ from Neutron Star Observations. https://arxiv.org/abs/2506.07546

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