Speaker
Description
Solutions to the dark matter puzzle and the hierarchy problem can include a BSM fermion $\psi$ that is a SM singlet and couples to the visible sector via a Higgs portal interaction: $\mathcal{L}_{H \psi} = c_{\psi}/f \ |H|^2 \bar{\psi} \psi$. Despite its potential of solving these tensions with the SM being well-established, the study of $\mathcal{L}_{H \psi}$ at hadron colliders remains challenging as the Higgs boson is the only portal between the $\psi$-particles and the SM sector. We study the interaction $\mathcal{L}_{H \psi}$ with several off-shell Higgs probes, namely the contribution of $\psi$ to the Higgs self-energy in $pp \rightarrow ZZ \rightarrow 4 \ell$ production, Di-Higgs production, and the direct production of $\psi$-pairs in off-shell Higgs decays. Finally, we present the combination of these three analyses providing complementary results and give an outlook on the collider reach of HL-LHC and other beyond-LHC $pp$-colliders in constraining the $\mathcal{L}_{H \psi}$ interaction.
