1203.0573 (Gorazd Cvetic et al.)

Probing Majorana neutrinos in rare $π^+ \to e^+ e^+ μ^- ν$ decays    [PDF]

Gorazd Cvetic, Claudio Dib, C. S. Kim

We study the rare decays of charged $\pi$ mesons, $\pi^+ \to e^+ e^+ \mu^- \bar\nu_\mu $ and $\pi^+ \to e^+ \mu^- e^+ \nu_e $ induced by a sterile neutrino $N$ with a mass in the range $m_\mu < m_N < m_\pi$. The first process violates Lepton Number by two units and so occurs only if $N$ is Majorana, while the second process conserves Lepton Number and occurs irrespective of the Majorana or Dirac character of $N$. We study a way to distinguish the Majorana vs. Dirac character of $N$ in these processes using the muon spectrum. We also find that the branching ratios could be at the reach of high luminosity experiments like Project X at FNAL or any proposed neutrino (or muon) factories worldwide.

View original: http://arxiv.org/abs/1203.0573