One-Loop Corrections to the Perturbative Unitarity Bounds in the $CP$-Conserving Two-Higgs Doublet Model with a Softly Broken $\mathbb{Z}_2$ Symmetry

TL;DR

This paper calculates one-loop corrections to unitarity bounds in the CP-conserving two-Higgs doublet model, providing refined constraints on the model's parameters at high energies.

Contribution

It presents the first comprehensive calculation of one-loop enhanced corrections to unitarity bounds in the two-Higgs doublet model with a softly broken Z2 symmetry.

Findings

Typical bounds on couplings are approximately 4 at high energies.

One-loop corrections significantly refine the unitarity constraints.

Results applicable to high-energy scattering processes in the model.

Abstract

We compute all of the one-loop corrections that are enhanced, $O(\lambda_i \lambda_j / 16 \pi^2)$, in the limit $s \gg |\lambda_i | v^2 \gg M_{W}^2$, $s \gg m_{12}^2$ to all the $2 \to 2$ longitudinal vector boson and Higgs boson scattering amplitudes in the $CP$-conserving two-Higgs doublet model with a softly broken $\mathbb{Z}_2$ symmetry. In the two simplified scenarios we study, the typical bound we find is $|\lambda_i(s)| \lessapprox 4$.