Loop effects on the Higgs decay widths in extended Higgs models

TL;DR

This paper calculates the decay widths of the 125 GeV Higgs boson in extended models, including one-loop corrections, to distinguish between models and infer properties of additional Higgs bosons from future precision data.

Contribution

It provides a detailed one-loop level analysis of Higgs decay widths in various extended models, enabling model discrimination and mass scale estimation without direct discovery.

Findings

Deviations in decay widths are distinctive for each model.

Radiative corrections allow discrimination of models with future data.

Deviations inform on the mass scale of extra Higgs bosons.

Abstract

In order to identify the Higgs sector using future precision data, we calculate the partial decay widths of the discovered Higgs boson with the mass of 125 GeV into fermion pairs and gauge-boson pairs with one-loop electroweak and one-loop QCD corrections in various extended Higgs models, such as the Higgs singlet model and four types of two Higgs doublet models. In the tree-level analysis, the patterns of deviations from the standard model predictions in the partial decay widths for various decay modes are distinctive for each model, due to the mixing of the Higgs boson with other neutral scalars. Our present analysis shows that even with a full set of radiative corrections we can discriminate these extended Higgs models via the partial decay widths as long as any of the deviations is detected at future precision measurements. Furthermore, we quantitatively show that in each model the magnitude of the deviations can provide important information on the mass scale of extra Higgs bosons under the theoretical constraints from perturbative unitary and vacuum stability, which can be obtained without discovery of the additional Higgs bosons.