Speaker
Description
Higgs couplings are essential probes for physics beyond the Standard Model (BSM), as the Higgs potential can be generically modified by new physics, particularly through the Higgs portal interaction $|H|^2\mathcal{O}$. These modifications influence Higgs interactions via dimension-6 operators of the form $\sim \left(\partial |H|^2\right)^2$ and $\sim |H|^6$, which are generally expected to be of comparable size. This paper discusses a phenomenon of accidental suppression, where the $|H|^6$ coupling is significantly smaller than $\left(\partial |H|^2\right)^2$. This suppression, arising from the truncation of the tree-level effective potential, lacks a clear symmetry explanation but persists in Higgs-portal and neutrino-portal couplings. We explore toy examples and a specific model--the Standard Model (SM) gauge singlet extension of the Standard Model--in detail, aiming to inspire further studies on additional instances of accidental suppression without symmetry explanations or a general framework to characterize such suppression. We also discuss future collider constraints on the Wilson coefficients of the two dimension-6 operators for various benchmark scenarios of the concrete model.
