Probing a pseudoscalar at the LHC in light of muon g ?2 and R( D (?)) excesses

摘要

We study the excesses of muon g ? 2 and R ( D ( ? ) ) in the framework of a two-Higgs-doublet model with top quark flavor-changing neutral-current (FCNC) couplings. Considering the relevant theoretical and experimental constraints, we find that the muon g ? 2 and R ( D ( ? ) ) excesses can be simultaneously explained in a parameter space allowed by the constraints. In such a parameter space the pseudoscalar ( A ) has a mass between 20 GeV and 150 GeV so that it can be produced from the top quark FCNC decay t → A c . Focusing on its dominant decay A → τ τ ˉ , we perform a detailed simulation on p p → t t ˉ → W b A c → j j b c τ τ ˉ and find that the 2 σ upper limits from a data set of 30 ( 100 ) fb ? 1 at the 13 TeV LHC can mostly (entirely) exclude such a parameter space.