Sub-GeV Dark Matter Direct Detection

by Riccardo Catena (Chalmers University of Technology)

Monday 26 May 2025, 14:30 → 16:00 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

In this talk, I will review recent progress in understanding how in-medium effects shape dark matter (DM)–electron interactions in direct detection experiments. I will outline a general formalism that combines the non-relativistic effective theory of DM–electron interactions with linear response theory, allowing for a unified treatment of screening and collective excitations across a wide range of detector materials. In this framework, the material's response to a DM perturbation is encoded in generalized susceptibilities, which can be directly related to charge and current densities emerging from the non-relativistic expansion of the Dirac Hamiltonian. I will illustrate how this approach clarifies the role of in-medium effects in determining experimental sensitivity—especially for DM that couples to electron density—and discuss its implications for both existing and future detector designs. The formalism naturally extends to spin-polarized systems, opening new avenues for exploring DM interactions in complex electronic environments.

catena.pdf