2025/07/18 by Taufertshöfer, Nora, Zema, Vanessa, Catena, Riccardo +2
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.2507.14345
We determine whether excitonic effects affect predictions of dark matter (DM)-electron scattering rates by calculating the energy- and momentum-dependent energy-loss function, including electron-hole interaction excitonic effects, for the dark-matter scintillating detector materials GaAs and NaI. By comparing our results using the Bethe-Salpeter equation in the framework of many-body perturbation theory, which explicitly includes excitonic effects, with those using the quasiparticle random-phase approximation, which includes only electron-electron interaction and crystal local-field effects, we find that excitonic effects in NaI significantly increase the predicted scattering rate at low energy and as a result improve the cross-section sensitivity considering a realistic background. In contrast, the predicted scattering rate and the DM-electron scattering cross-section for GaAs are minimally affected by excitonic effects.