Phenomenology of the companion-axion model: photon couplings Zhe Chen, Archil Kobakhidze, Ciaran A. J. O’Hare, Zachary S. C. Picker and Giovanni Pierobon Eur. Phys. J. C, 82 10 (2022) 940 Published online: 23 October 2022 DOI: 10.1140/epjc/s10052-022-10909-6