Unitarity constraints on 2HDM with higher dimensional operators
Abstract
We study how the requirement of perturbative unitarity restricts the parameter space of the two-Higgs-doublet model (2HDM) when higher-dimensional operators up to dimension six are included. We demonstrate that such operators can enhance scalar production cross sections in vector boson fusion relative to 2HDM. Using S-matrix unitarity, we place bounds on several dimension-six bosonic operators. We also find that certain blind directions in the Wilson coefficients of T-parameter violating operators which are poorly constrained by electroweak precision data can be partially excluded when unitarity constraints are taken into account. These results demonstrate how high-energy consistency can complement experimental limits in defining the allowed parameter space of 2HDM effective field theory.
Cite
@article{arxiv.2601.01464,
title = {Unitarity constraints on 2HDM with higher dimensional operators},
author = {Deepak Sah},
journal= {arXiv preprint arXiv:2601.01464},
year = {2026}
}