Comprehensive study of two Higgs doublet model in light of the new boson with mass around 125 GeV

TL;DR

This paper analyzes the compatibility of various two Higgs doublet models with the 125 GeV boson discovery, using a global fit to experimental data, and finds certain models fit better than the Standard Model.

Contribution

It performs a comprehensive global fit of four types of two Higgs doublet models considering multiple scenarios and experimental constraints, identifying which models align with observed data.

Findings

Type II and Y models fit the data as well as or better than the SM.

Most other two Higgs doublet models are excluded at 95% confidence level.

The scenario where the 125 GeV boson is the light CP-even Higgs is favored in some models.

Abstract

The recent discovery of a new boson of mass roughly 125 GeV has been reported by the ATLAS and CMS collaborations. Although its signals in various decay modes resemble those of the standard model (SM) Higgs boson, observed are the combinations of entangled information about the production, decay rates and total decay width of the new boson. In addition, some decay channels show non-negligible deviation from the SM expectation, such as the $2\sigma$ excess in the diphoton channel. In the four types (I, II, X and Y) of two Higgs doublet models, we perform the global $\chi^2$ fit in three scenarios: (i) the new boson is the light CP-even Higgs boson $h^0$; (ii) it is the heavy CP-even Higgs boson $H^0$; (iii) the signals are from degenerate $h^0$ and the pseudoscalar $A^0$. Considering other phenomenological constraints such as flavor physics, electroweak precision data, and the LEP search for the Higgs boson, we find that the the first scenarios in Type II and Type Y models actually provide better or similarly good fit to the data than the SM. All the other models are excluded at 95% C.L..