1. The problem statement, all variables and given/known data Draw feynman diagrams for pi+ muon lepton decay and suggest which process is more likely. 2. Relevant equations 3. The attempt at a solution The feynman diagrams are: The lepton decays proceed via the weak interaction W+ boson. This implies that e+ should be right-handed and neutrino is always left-handed. In the rest frame of W+, we get: But this implies that total spin = 1, which is not true. Therefore, e+ must be left-handed?