Novel collider and dark matter phenomenology of a top-philic Z ′

Abstract

We consider extending the Standard Model by including an additional Abelian gauge group broken at low energies under which the right-handed top quark is the only effectively charged Standard Model fermion. The associated gauge boson (Z′) is then naturally top-philic and couples only to the rest of the SM particle content at loop-level or via kinetic mixing with the hypercharge gauge boson which is assumed to be small. Working at the effective theory level, we demonstrate that such a minimal extension allows for an improved fitting of the ∼ 2σ excess observed in tt¯ h searches at the LHC in a region of parameter space that satisfies existing collider constraints. We also present the reach of ..