Heavy Majorana neutrinos in the effective Lagrangian description: Application to hadron colliders

摘要

We consider the effects of heavy Majorana neutrinos N with sub-TeV masses and argue that the mere observation of these particles would be a signal of physics beyond the minimal seesaw mechanism. We describe the N interactions using an effective Lagrangian and exhibit the complete set of effective operators of dimension ≤6 involving the N and Standard Model fields. We argue that these interactions can be relatively easy to track at high-energy colliders. For example, we find that new physics (beyond the N) at the TeV-scale can yield thousands of characteristic same-sign lepton number violating e+e+jj events (j = light jet) at the LHC if m_N < 600 GeV, which can also have a distinctive forward-backward asymmetry signal: even the Tevatron has good prospects for this signature if m_N < 300 GeV.