Majorana vs. Dirac sterile neutrinos at the LHC

We study leptonic decays W± → e±e±μ∓ν and W± → μ±μ±e∓ν which would
occur at the LHC if there exist sterile neutrinos with masses below MW . We also study ways to
discriminate their Majorana or Dirac character, a rather non trivial task, because lepton number
conservation cannot be checked due to the missing neutrino in the final state. We find that it
is indeed possible to discriminate between Majorana vs. Dirac sterile neutrinos by comparing
the production of e±e±μ∓ vs. μ±μ±e∓ if the N-e and N-μ mixings are sufficiently different.
Alternatively, one could also distinguish the Majorana vs. Dirac character by studying the
energy spectra of the opposite charge lepton, a method that works even for equal N-e and N-μ
mixings.