Given the masses of various atomic particles mp = 1.0072 u, mn = 1.0087 u, me = 0.000548 u, mv[bar] = 0, md = 2.0141 u, where p ≡ proton, n ≡ neutron, e ≡ electron, v [bar] ≡ antineutrino and d ≡ deuteron. Which of the following processes is allowed by momentum and energy conservation? 1) n + n deuterium atom (electron bound to the nucleus) 2) e+ + e– → γ 3) p → n + e+ + v [bar] 4) n + p → d + γ

Given the masses of various atomic particles mp = 1.0072 u, mn = 1.0087 u, me = 0.000548 u, mv[bar] = 0, md = 2.0141 u, where p ≡ proton, n ≡ neutron, e ≡ electron, v [bar] ≡ antineutrino and d ≡ deuteron. Which of the following processes is allowed by momentum and energy conservation? 1) n + n deuterium atom (electron bound to the nucleus) 2) e+ + e– → γ 3) p → n + e+ + v [bar] 4) n + p → d + γ