Revisiting lepton-specific 2HDM in light of muon g-2 anomaly

Abstract

We examine the lepton-specific 2HDM as a solution of muon $g-2$ anomaly under various theoretical and experimental constraints, especially the direct search limits from the LHC and the requirement of a strong first-order phase transition in the early universe. We find that the muon g-2 anomaly can be explained in the region of 32 $<\tanβ<$ 80, 10 GeV $<m_A<$ 65 GeV, 260 GeV $<m_H<$ 620 GeV and 180 GeV $<m_{H^\pm}<$ 620 GeV after imposing the joint constraints from the theory, the precision electroweak data, the 125 GeV Higgs data, the leptonic/semi-hadronic $τ$ decays, the leptonic $Z$ decays and Br$(B_s \to μ^+ μ^-)$. The direct searches from the $h\to AA$ channels can impose stringent upper limits on Br$(h\to AA)$ and the multi-lepton event searches can sizably reduce the allowed region of $m_A$ and $\tanβ$ (10 GeV $<m_A<$ 44 GeV and 32 $<\tanβ<$ 60). Finally, we find that the model can produce a strong first-order phase transition in the region of 14 GeV $<m_A<$ 25 GeV, 310 GeV $<m_H<$ 355 GeV and 250 GeV $<m_{H^\pm}<$ 295 GeV, allowed by the explanation of the muon $g-2$ anomaly.