Speaker
Description
We propose a novel detection strategy for super-light dark matter (DM), m_DM ~ O(keV), using a detector based on Graphene Josephson Junctions (GJJ). By intimately integrating the π-bond electrons of graphene as the target material into a Josephson junction, we create a sensor capable of detecting energy deposits as small as O(meV). We evaluate the scattering rates between DM and free electrons in the two-dimensional graphene, incorporating Pauli-blocking factors and in-medium screening effects. Our analysis of pg- to µg-scale detectors demonstrates that this setup achieves superior experimental sensitivity due to its extremely low energy threshold. Furthermore, we demonstrate that this 2D direct detection framework allows for the determination of the DM mass scale through directionality observables. Due to the relative motion of the Earth through the Galactic DM halo, the event rates depend non-trivially on the orientation of the graphene plane relative to the DM flux. We show that the curvature of this resulting angular spectrum encodes critical information about the particle mass. By validating these theoretical expectations through numerical analysis of the GJJ detector, we establish that this platform serves not only as a highly sensitive probe for the discovery of super-light DM but also as a precision instrument for measuring its fundamental properties.