Bounds on heavy axions with an X-ray free electron laser
Physical Review Letters American Physical Society 134:5 (2025) 55001
Authors:
Jack WD Halliday, Giacomo Marocco, Konstantin A Beyer, Charles Heaton, Motoaki Nakatsutsumi, Thomas R Preston, Charles Arrowsmith, Carsten Baehtz, Sebastian Goede, Oliver Humphries, Alejandro Laso Garcia, Richard Plackett, Pontus Svensson, Georgios Vacalis, Justin Wark, Daniel Wood, Ulf Zastrau, Robert Bingham, Ian Shipsey, Subir Sarkar, Gianluca Gregori
Abstract:
We present new exclusion bounds obtained at the European X-Ray Free Electron Laser facility (EuXFEL) on axionlike particles in the mass range $10^{-3}\,\mathrm{eV} \lesssim m_a \lesssim 10^{4}\,\mathrm{eV}$. Our experiment exploits the Primakoff effect via which photons can, in the presence of a strong external electric field, decay into axions, which then convert back into photons after passing through an opaque wall. While similar searches have been performed previously at a third-generation synchrotron [Yamaji et al., Phys.\ Lett.\ B 782, 523 (2018)], our work demonstrates improved sensitivity, exploiting the higher brightness of x-rays at EuXFEL.
