Low-energy Compton scattering is an important background for sub-GeV dark matter direct-detection and other experiments. Current Compton scattering calculations typically rely on assumptions that are not valid in the low-energy region of interest, beneath ~ 50 eV. Here we relate the low-energy Compton scattering differential cross section to the dielectric response of the material. Our new approach can be used for a wide range of materials and includes all-electron, band structure, and collective effects, which can be particularly relevant at low energies. We demonstrate the strength of our approach in several solid-state systems, in particular Si, Ge, GaAs, and SiC, which are relevant for current and proposed experiments searching for dark matter, neutrinos, and millicharged particles.
@article{arxiv.2310.02316,
title = {Low-Energy Compton Scattering in Materials},
author = {Rouven Essig and Yonit Hochberg and Yutaro Shoji and Aman Singal and Gregory Suczewski},
journal= {arXiv preprint arXiv:2310.02316},
year = {2023}
}