Speaker
Description
GeV-scale thermal dark matter is often considered to be strongly constrained by the null results of direct, indirect, and collider searches. Nevertheless, viable scenarios can still arise in well-motivated dark sector frameworks. In this talk, we explore this possibility in a dark Abelian Higgs model with a Dirac fermion dark matter candidate interacting with the Standard Model through a dark photon mediator. We focus on the intermediate mass regime for the mediator, between 10 GeV and the mass of the Z boson, which lies beyond the reach of B factories and below the typical sensitivity of the LHC, and has been comparatively underexplored in the literature.
We perform a comprehensive analysis of the complementarity between collider probes, direct detection, and indirect detection experiments, while consistently accounting for the possibility that the our candidate constitutes only a fraction of the observed dark matter relic abundance. This dilution effect relaxes the experimental limits by suppressing direct and indirect detection signals according to the dark matter relic abundance. Despite the strong experimental pressure, we show that thermal GeV-scale dark matter is cornered but still viable. The allowed parameter space is restricted to narrow regions near the resonant regime, $m_\chi\approx m_{Z_D}/2$, where dark matter annihilation in the early universe is enhanced. In this regime, direct detection experiments provide the strongest constraints, while collider searches offer complementary sensitivity for sizeable values of the kinetic mixing. Future results from both direct detection and colliders will play a crucial role in testing these remaining windows, making GeV-scale dark photon portals an attractive target for upcoming experiments.
This talk is based on 2507.11376.