LHC τ-rich tests of lepton-specific 2HDM for (g−2)_μ

The lepton-sepcific (or type X) 2HDM (L2HDM) is an attractive new physics candidate explaining the muon g−2 anomaly requiring a light CP-odd boson A and large tan β. This scenario leads to τ-rich signatures, such as 3τ, 4τ and 4τ+W/Z, which can be readily accessible at the LHC. We first study the whole L2HDM parameter space to identify allowed regions of extra Higgs boson masses as well as two couplings λ_hAA and ξ_h^l which determine the 125 GeV Higgs boson decays h→τ⁺τ⁻ and h→AA/AA^∗(τ⁺τ⁻), respectively. This motivates us to set up two regions of interest: (A) m_A≪m_H∼m_H^±, and (B) m_A∼m_H^±∼O(100)GeV≪m_H, for which derive the current constraints by adopting the chargino-neutralino search at the LHC8, and then analyze the LHC14 prospects by implementing τ-tagging algorithm. A correlated study of the upcoming precision determination of the 125 GeV Higgs boson decay properties as well as the observation of multi-tau events at the next runs of LHC will be able to shed light on the L2HDM option for the muon g−2.