A study on vector mediator top-philic dark matter

We conducted a study on a simplified dark matter model that introduces a vector-like intermediate particle,facilitating exclusive interactions between dark matter and the top quark in the Standard Model.The analysis focused on the relic density of Dirac-type fermion dark matter and highlighted the complementary role of direct detection in constraining the dark matter model.Notably,in instances when dark matter mass is small,the tree-level two-body annihilation process experiences suppression.In such scenarios,the contributions of the threebody process(χχ→tbW-)and the one-loop process(χχ→gg)dominate the relic abundance.With regard to direct detection,calculations were performed for the two-loop contribution to the dark-matter-gluon interaction,yielding the corresponding spin-independent scattering cross section.