Probing the Symmetric Higgs Portal with Di-Higgs Boson Production

Understand

A coupling of a scalar, charged under an unbroken global U(1) symmetry, to the Standard Model via the Higgs portal is one of the simplest gateways to a dark sector.

• Yet, for masses $m_{S}\geq m_{H}/2$ there are few probes of such an interaction.
• In this note we evaluate the sensitivity to the Higgs portal coupling of di-Higgs boson production at the LHC as well as at a future high energy hadron collider, FCC-hh, taking into account the full momentum dependence of the process.
• This significantly impacts the sensitivity compared to estimates of changes in the Higgs-coupling based on the effective potential.