Bounds on Heavy Axions with an X-Ray Free Electron Laser
Jack Halliday, Giacomo Marocco, Konstantin A. Beyer, Charles Heaton, M. Nakatsutsumi, Thomas R. Preston, Charles Arrowsmith, Carsten Baehtz, Sebastian Goede, Oliver Humphries, Alejandro Laso García, R. Plackett, Pontus Svensson, Georgios Vacalis, J. S. Wark, Daniel Wood, U. Zastrau, R. Bingham, I. P. J. Shipsey, S. Sarkar, G. 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} eV≲m_{a}≲10^{4} 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)PYLBAJ0370-269310.1016/j.physletb.2018.05.068], our work demonstrates improved sensitivity, exploiting the higher brightness of x-rays at EuXFEL.