Constraining the Higgs-dilaton with LHC and dark matter searches

We study a scenario in which the dilaton, a pseudo-Goldstone boson of the spontaneous breaking of conformal symmetry, provides a portal between dark matter and the visible sector. We consider the low-energy description of the theory in which the dilaton mixes with the Standard Model Higgs boson, thereby predicting a second scalar at or above the weak scale. We derive the collider and dark matter constraints on the corresponding parameter space and find that existing experimental data point towards the decoupling limit in which the conformal symmetry scale is well above the electroweak scale. Moreover, the thermal production of dark matter implies its mass is likely above the TeV scale. Upcoming direct-detection experiments may allow for the discovery of the dilaton-mediated thermal dark matter while future collider studies will also be sensitive to the available parameter space.