Lepton-Specific Two-Higgs Doublet Model: Experimental Constraints and Implication on Higgs Phenomenology

TL;DR

This paper investigates the lepton-specific two-Higgs doublet model, analyzing experimental constraints and their implications on Higgs boson properties, revealing a light CP-odd Higgs and challenging Higgs detection at the LHC.

Contribution

It provides a comprehensive analysis of experimental constraints on the lepton-specific 2HDM and explores its unique Higgs phenomenology, especially the light CP-odd Higgs and altered decay modes.

Findings

CP-odd Higgs A is likely lighter than 30 GeV

Higgs h decays mainly into four tau leptons

Branching ratio Br(Z→τ+τ−A) is within 10^{-5} to 10^{-4}

Abstract

We examine various direct and indirect constraints on the lepton-specific two-Higgs doublet model and scrutinize the property of the Higgs bosons in the allowed parameter space. These constraints come from the precision electroweak data, the direct search for Higgs boson, the muon anomalous magnetic moment, as well as some theoretical consistency requirements. We find that in the allowed parameter space the CP-odd Higgs boson A is rather light (m_A < 30 GeV with 95% possibility), which is composed dominantly by the leptonic Higgs and decays dominantly into \tau^+ \tau^-; while the SM-like Higgs boson h (responsible largely for electroweak symmetry breaking) decays dominantly in the mode h->A A->4 \tau with a large decay width, which will make the Higgs discovery more difficult at the LHC. Whereas, this scenario predicts a branching ratio Br(Z->\tau^+ \tau^- A) ranging from 10^{-5} to 10^{-4}, which may be accessible at the the GigaZ option of the ILC.