Search for Light Dark Sectors Using Electron-Photon Collisions

Abstract: The dark photon is a new gauge boson that naturally arises in many beyond the Standard Model theoretical models, featuring interactions that resemble quantum electrodynamics. Due to this feature, it is often considered the portal between dark and visible sectors. For this reason, it has become the target of many experimental searches worldwide. In this work, we propose a search for dark photons based on the Inverse Compton scattering, $γe^- \rightarrow A^\prime e^-$, to be conducted at electron accelerators. In this setup, photons from a laser source would impinge on the accelerated electron beam, producing a dark photon in the final state. We propose an experimental setup to take advantage of the photon counting technique, and we derive the projected sensitivity by considering the energy of the incident photon to be about 1 eV and an electron beam of 3 GeV. We show that this experimental setup could cover an unexplored region of parameter space and constitute a promising probe for dark sectors in the future.