Atoms as electron accelerators: leveraging atomic electron momentum distribution in fixed target experiments
by
Aula Salvini
Laboratori Nazionali di Frascati
Resonant positron annihilation on atomic electrons is a powerful technique for searching for light dark matter particles that couple to e+e-. Accurate estimates of production rates necessitate a detailed characterization of atomic electron momentum distributions. I will present a general method that uses the Compton profile of the target material to accurately account for electron velocity effects in resonant annihilation cross-sections. Additionally, I will discuss the implications of this precise computation for new physics searches and how high Z atoms can effectively serve as electron accelerators, thereby extending the experimental mass reach. Finally, I will demonstrate that leveraging the relativistic velocities of electrons in the inner atomic shells, a high-intensity 12 GeV positron beam — such as the one planned at JLab — can allow to measure the hadronic cross section with high statistical accuracy. This seminar is based on Phys.Rev.Lett. 132 (2024) 26, 261801 and hep-ph/2407.15941.
