Probing the Dirac or Majorana nature of the heavy neutrinos in pure leptonic decays at the LHC

We propose a strategy for distinguishing the Dirac / Majorana character of heavy neutrinos with masses below the W boson mass, using purely leptonic decays at the LHC. The strategy makes use of a forward-backward asymmetry of the opposite charge lepton in the W+→l+l+l′−ν decay. In order to check the experimental feasibility of the model, we show, through a numerical analysis, that in the decay W+→e+e+μ−ν the two positrons in the final state can be distinguished for different ranges of the heavy neutrino masses. Finally, we estimated the number of events of W+→e+e+μ−ν for a Dirac and Majorana N neutrino. For an integrated luminosity of 120 fb−1 at LHC RUN II, signals can be found if heavy-to-light neutrino mixings are |UNμ|^2,|UNe|^2≳10−6.