Radiative corrections to Higgs coupling constants in two Higgs doublet models

TL;DR

This paper calculates one-loop level deviations in Higgs couplings within various Two Higgs Doublet Models, showing that precise measurements at the ILC can distinguish between different model types even without direct detection of extra Higgs bosons.

Contribution

It provides a comprehensive calculation of radiative corrections to Higgs Yukawa couplings in all four types of THDMs, enabling indirect identification of the model type through collider measurements.

Findings

Deviations in Yukawa couplings can reach a few percent due to loop effects.

Large deviations in gauge couplings at the ILC can differentiate THDM types.

Radiative corrections help distinguish models without direct Higgs searches.

Abstract

A pattern of deviations in the Standard Model (SM) like Higgs boson ($h$) couplings from their SM predictions depends on the structure of the Higgs sector and the Yukawa interaction. In particular, in Two Higgs Doublet Models (THDMs) with a softly-broken $Z_2$ symmetry, different characteristic patterns of deviation in Yukawa coupling constants ($hf\bar{f}$) can be allowed depending on four types of Yukawa interactions. We calculate $hf\bar{f}$ coupling constants at the one-loop level in all the types of THDMs. Even if there is no deviation in the $hf\bar{f}$ couplings at the tree level, they can deviate from the SM predictions by a few percent due to extra Higgs boson loop contributions. We find that if the deviations in the gauge couplings $hVV$ ($V=Z, W$) are found with an enough large to be measured at the International Linear Collider (ILC), the scale factors for the $hf\bar{f}$ couplings do not overlap among the THDMs with four types of Yukawa interactions even taking into account the radiative corrections. Therefore, in such a case, we can indirectly determine the type of the THDMs at the ILC even without information from direct searches of the additional Higgs bosons.