A neutron (mn = 939.6 MeV/c2) at rest decays into a proton (mp = 938.3 MeV/c2), an

Question:

A neutron (mn = 939.6 MeV/c2) at rest decays into a proton (mp = 938.3 MeV/c2), an electron (me = 0.5 MeV/c2), and an antineutrino (m0 ≈ 0). The three particles emerge at symmetrical angles in a plane, 120o apart. Find the momentum and kinetic energy of each particle.