Novel Collider and Dark Matter Phenomenology of a Top-philic Z'

Understand

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 $\sim 2\sigma$ excess observed in $t\bar{t}h$ searches at the LHC in a region of parameter space that satisfies existing collider constraints.
• We also present the reach of the LHC at 13 TeV in constraining the relevant region of parameter space.