Muon g$-$2 in two-Higgs-doublet models

TL;DR

This paper updates constraints on two-Higgs-doublet models and finds that only the lepton-specific type can account for the muon g$-$2 anomaly within certain parameter regions, considering various experimental and theoretical limits.

Contribution

It demonstrates that the lepton-specific 2HDM uniquely explains the muon g$-$2 anomaly under combined constraints, highlighting the importance of specific parameter choices.

Findings

Only the lepton-specific 2HDM explains the muon g$-$2 anomaly.

The viable parameter space involves large tanβ and a light CP-odd boson.

Severe constraints come from vacuum stability, electroweak precision data, and LHC measurements.

Abstract

Updating various theoretical and experimental constraints on the four different types of two-Higgs-doublet models (2HDMs), we find that only the ``lepton-specific" (or ``type X") 2HDM can explain the present muon g$-$2 anomaly in the parameter region of large $\tan\beta$, a light CP-odd boson, and heavier CP-even and charged bosons which are almost degenerate. The severe constraints on the models come mainly from the consideration of vacuum stability and perturbativity, the electroweak precision data, the $b$-quark observables like $B_S \to \mu\mu$, the precision measurements of the lepton universality as well as the 125 GeV boson property observed at the LHC.