2021/05/31 by Andrea Caputo, Alexander J. Millar, Ciaran A. J. O’Hare +3 · 268 citations
Physics and Astronomy · #Astrophysics #Axion #Computer science #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark matter #Dark photon #Mixing (physics) #Particle physics #Particle physics theoretical and experimental studies #Photon #Physics #Quantum mechanics #Rotation (mathematics) #Standard Model (mathematical formulation) #astro-ph.HE #hep-ex #hep-ph #physics.ins-det
paper · pdf · open access · doi:10.1103/physrevd.104.095029
published in Physical review. D/Physical review. D. 104(9) (American Physical Society) · 32 pages, 11 figures. Code to reproduce the main results can be found at https://github.com/cajohare/DarkPhotonCookbook whereas code and data for making limit plots can be found at https://cajohare.github.io/AxionLimits. Matches published version
openalex publication_date 2021/11/29 · arxiv created 2021/12/01 · arxiv updated 2021/12/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The dark photon is a massive hypothetical particle that interacts with the Standard Model by kinetically mixing with the visible photon. For small values of the mixing parameter, dark photons can evade cosmological bounds to be a viable dark matter candidate. Due to the similarities with the electromagnetic signals generated by axions, several bounds on dark photon signals are simply reinterpretations of historical bounds set by axion haloscopes. However, the dark photon has a property that the axion does not: an intrinsic polarisation. Due to the rotation of the Earth, accurately accounting for this polarisation is nontrivial, highly experiment-dependent, and depends upon assumptions about the dark photon's production mechanism. We show that if one does account for the DP polarisation, and the rotation of the Earth, an experiment's discovery reach can be enhanced by over an order of magnitude. We detail the strategies that would need to be taken to properly optimise a dark photon search. These include judiciously choosing the location and orientation of the experiment, as well as strategically timing any repeated measurements. Experiments located at ±35^∘ or ±55^∘ latitude, making three observations at different times of the sidereal day, can achieve a sensitivity that is fully optimised and insensitive to the dark photon's polarisation state, and hence its production mechanism. We also point out that several well-known searches for axions employ techniques for testing signals that preclude their ability to set exclusion limits on dark photons, and hence should not be reinterpreted as such.