3 ms·

Why do neutrons bound with a proton 'live' substantially longer?

• krastanov 8y ago
  An extremely handwavy explanation would be that they do not: the neutron decays into a proton and other stuff. That other stuff is captured by a proton that becomes a neutron. This is borderline metaphoric, but it gives a gist of the physics.
• tim333 8y ago
  >Spontaneous processes such as neutron decay require that the final state is lower in energy than the initial state. In (stable) nuclei, this is not the case, because the energy you gain from the neutron decay is lower than the energy it costs you to have an additional proton in the core. https://physics.stackexchange.com/questions/9098/how-come-neutrons-in-a-nucleus-dont-decay https://physics.stackexchange.com/questions/9098/how-come-ne...
• davrosthedalek 8y ago
  Because that's a lower energy state. The deuteron binding energy is 2.2 MeV, i.e. the mass of a deuteron is 2.2 MeV below the sum of the masses of a proton + neutron. If the neutron inside would decay into a proton, you would have a diproton (^2He). Very unstable, essentially no binding energy, so it's mass is very close to 2 protons, which is still above the deuteron mass. So the neutron can not decay spontaneously. There is not enough energy available.