Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It only takes a minute to sign up.
Sign up to join this community
I am confused by a simple fact about the $\beta^{-}$ decay of ${}^{60}{\rm Co}$ nucleus. According to Wikipedia, the most likely decay branch is to an excited state of ${}^{60}{\rm Ni}$, see the diagram:
But the energy indicated on the diagram (0.31 MeV) is less than the electron rest mass (0.511 MeV)! How is that possible?
When they show a decay with a certian amount of energy, this energy is net of the masses of the particles. So you get Co = $\beta$ + Ni + 0.31 MeV, the energy is attached to the ejected beta particle.
