A neutron decays into a proton by emitting an electron and an electron antineutrino.<p>A proton decays into a neutron by emitting a positron and an electron neutrino. (These are the antiparticles of the ones emitted in neutron to proton beta decay, above.)<p><a href="https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Beta_decay" rel="nofollow">https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Beta_decay</a>