Phenomenology of excited doubly charged heavy leptons at LHC

Abstract

We consider the production at the LHC of exotic composite leptons of charge Q=_s162e. Such states are allowed in composite models which contain extended isospin multiplets (Iw=1 and Iw=3/2). These doubly charged leptons couple with Standard Model [SM] fermions via gauge interactions, thereby delineating and restricting their possible decay channels. We discuss the production cross section at the LHC of L_s16_s16 (p p --> L_s16_s16, l-) and concentrate on the leptonic signature deriving from the cascade decays L_s16_s16 --> W_s16, l_s16 --> l_s16, l_s16, nu_l i.e. p p --> l-, l_s16, l_s16, nu_l showing that the invariant mass distribution of the like-sign dilepton has a sharp end point corresponding to excited lepton mass m*. We find that the sqrt{s}=7 TeV run is sensitive at the 3-sigma (5-sigma) level to a mass of the order of 600 GeV if L=10 fb^-1 (L=20 fb^-1). The sqrt{s}=14 TeV run can reach a sensitivity at 3-sigma (5-sigma) level up to m*=1 TeV for L=20 fb^-1 (L=60 fb^-1).