Constraints on Leptophilic Light Dark Matter from Internal Heat Flux of Earth

Direct Detection experiments have severely constrained the parameter space for WIMP Dark Matter in the mass range 1–100 GeV. However, there are few constraints on low mass dark matter due to insufficient nuclear recoil. If Dark Matter is leptophilic, then for low masses, its scattering cross section with electrons is significantly higher than nucleons. Dark matter form the local neighbourhood can scatter from the electrons of earth and then be captured. Subsequent annihilation inside Earth generates heat that can be compared with experimentally measured value.