# Experimental evidence of two neutrinos in muon decay?

We know that the pion decays into a lepton/neutrino pair while the muon decays into a muon neutrino, electron and electron neutrino. How do we distinguish them experimentally? Would the muon decay have two 'missing widths' compared to the pion decay?

• What do you want to distinguish here ? Decaying muon from decaying pions ? – agemO Jun 10 '15 at 13:23