How about this:
p(muon) = p(antineutrino) = p
E(antineutrino) = pc
E(muon) = sqrt[(pc)^2+(mc^2)^2]
plug these into conservation of E and solve for p
after some math I get
p = 29.79 MeV/c
so E(antineutrino) = 29.79 MeV
E(muon) = 109.78 MeV
The two E's add up to equal E(pion), 139.57
Homework Statement
A pion at rest decays into a muon and an antineutrino. The mass of the antineutrino is zero, find the energies and momenta of the muon and antineutrino. Mass of the pion is 139.57 MeV/c^2 and the mass of the muon is 105.66 MeV/c^2
Homework Equations
pion -> muon +...