DM-electron scattering in materials: sum rules and heterostructures

Abstract

In recent years, a growing experimental program has begun to search for sub-GeV dark matter through its scattering with electrons. An associated theoretical challenge is to compute the dark matter scattering rate in experimental targets, and to find materials with large scattering rates. In this paper we point out that, if dark matter scatters through a mediator that couples to EM charge, then electromagnetic sum rules place limits on the achievable scattering rates. These limits serve as a useful sanity check for calculations, as well as setting a theoretical target for proposed detection methods. Motivated by this analysis, we explore how conductor-dielectric heterostructures can result in enhanced scattering rates compared to bulk conductors, for dark matter masses $\lesssim$ MeV. These effects could be especially important in computing the scattering rates from thin-film targets, e.g. superconducting detectors such as SNSPDs, TESs or MKIDs, for which the scattering rate could be enhanced by orders of magnitude at low enough dark matter masses, as well as introducing or enhancing directional dependence.

17 pages, 10 figures; v3, approximately matches version published in PRD

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Cited by in corpus (11)

• Dark matter - electron interactions in materials beyond the dark photon model
• Directional detection of dark matter with anisotropic response functions
• Effective Field Theory for Dark Matter Absorption on Single Phonons
• First Sub-MeV Dark Matter Search with the QROCODILE Experiment Using Superconducting Nanowire Single-Photon Detectors
• Freeze-in, glaciation, and UV sensitivity from light mediators
• Linear response theory for light dark matter-electron scattering in materials
• Collective excitations and low-energy ionization signatures of relativistic particles in silicon detectors
• The Non-Relativistic Effective Field Theory Of Dark Matter-Electron Interactions
• A general upper bound on the light dark matter scattering rate in materials
• New constraints on dark matter from superconducting nanowires
• First direct search for light dark matter interactions in a transition-edge sensor