Improved Dark Photon Sensitivity from the Dark SRF Experiment
Saarik Kalia, Zhen Liu, Bianca Giaccone, Oleksandr Melnychuk, Roman Pilipenko, Asher Berlin, Anson Hook, Sergey Belomestnykh, Crispin Contreras-Martinez, Daniil Frolov, Timergali Khabiboulline, Yuriy Pischalnikov, Sam Posen, Oleg Pronitchev, Vyacheslav Yakovlev, Anna Grassellino, Roni Harnik, Alexander Romanenko
Published: 2025/10/2
Abstract
We report the refined dark-photon exclusion bound from Dark SRF's pathfinder run. Our new result is driven by improved theoretical modeling of frequency instability in high-quality resonant experiments. Our analysis leads to a constraint that is an order of magnitude stronger than previously reported (corresponding to a signal-to-noise ratio that is four orders of magnitude larger). This result represents the world-leading constraint on non-dark-matter dark photons over a wide range of masses below $6\,\rm \mu eV$ and translates to the best laboratory-based limit on the photon mass $m_\gamma<2.9\times 10^{-48}\,\rm g$.