Implications of the precision data for very light Higgs boson scenario in 2HDM(II)

TL;DR

This paper analyzes how current precision data constrain the Two-Higgs-Doublet Model of type II, especially regarding the possibility of very light Higgs bosons below 30 GeV, showing the model remains consistent with electroweak measurements.

Contribution

It provides updated constraints on light Higgs bosons in 2HDM(II), highlighting scenarios with a light CP-odd Higgs and large tanβ that are compatible with data.

Findings

Light Higgs bosons below 20-30 GeV are still allowed in 2HDM(II).

The model can fit electroweak precision data as well as the Standard Model.

Lower mass limits on the lighter CP-even Higgs are derived in specific scenarios.

Abstract

We present an up-to-date analysis of the constraints imposed bythe precision data on the ($CP-$ conserving) Two-Higgs-Doublet Model of type II, with emphasis on the possible existence of very light neutral (pseudo)scalar Higgs boson with mass below 20--30 GeV. We show that even in the presence of such light particles, the 2HDM(II) can describe the electroweak data with precision comparable to that given by the SM. Particularly interesting lower limits on the mass of the lighter neutral $CP-$even scalar $h^0$ are obtained in the scenario with a light $CP-$odd Higgs boson $A^0$ and large $\tan\beta$.