Bounds on LFV Higgs decays in a vector-like lepton model and searching for doubly charged leptons at the LHC

The Higgs-portal lepton flavor violation is studied in a vector-like lepton model. To avoid the constraints from rare Z→ℓi±ℓj∓ decays, we introduce two triplet vector-like leptons, (1 , 3) _{- 1} and (1 , 3) ₀. The resultant branching ratio for h→ μτ can be up to 10 ^{- 4} when the constraints from the invisible Z decays are applied. As a result, the signal strength for the ττ channel has a 12% deviation from the standard model prediction, while the muon g- 2 is two orders of magnitude smaller than the data, and BR (τ→ μγ) is of the order of 10 ^{- 12}. A predicted doubly charged lepton in pp collisions at s=13 TeV is analyzed, and it is found that the interesting production channels are pp→(Ψ1--Ψ1++,Ψ1±±Ψ1∓). Both single and pair production cross sections of Ψ1++ are comparable, and can be a few hundred fb. The main decay channels for the doubly charged lepton are Ψ ^{± ±}→ ℓ^±W^±, and for the heavy singly charged lepton they are Ψ1±→νW±,ℓ±Z. The numerical analysis is carried out with regard to 13 TeV LHC with 100 fb^{- 1} luminosity.