Leptonic Precision Test of Leptophilic Two-Higgs-Doublet Model

TL;DR

This paper investigates how leptonic precision measurements constrain the parameter space of the leptophilic two-Higgs-doublet model, especially regarding the light pseudoscalar and heavy Higgs masses, in light of muon g-2 and lepton universality data.

Contribution

It provides a comprehensive analysis of leptonic precision constraints on the leptophilic 2HDM, identifying viable parameter regions consistent with current experimental data.

Findings

No 1σ overlap in parameter space, but 2σ viable regions exist.

Viable regions for heavy Higgs masses around 200-400 GeV.

Constraints from lepton universality significantly restrict model parameters.

Abstract

The type X (lepton-specific) two-Higgs-doublet model at large $\tan\beta$ becomes leptophilic and thus allows a light pseudoscalar $A$ accommodating the observed muon $g-2$ deviation without conflicting with various hadronic constraints. On the other hand, it is strongly constrained by leptonic precision observables such as lepton universality test in the neutral and charged currents. Treating all the lepton universality data in a consistent way, we show how the current data constrain the parameter space of $m_A$ and $\tan\beta$ for given degenerate masses of heavy Higgs bosons $H$ and $H^\pm$. While no overlapping region is found at $1\sigma$, a sizable region is still viable at $2\sigma$ for $H/H^\pm$ masses at around 200$\sim$400 GeV.