I've been reading in Weinberg's Lectures on Quantum Mechanics and in a note under the text it said that I can use the Clebsch-Gordan Coefficients to show that a neutron can't decay into a proton and electron.
Now I know it's referring to the betadecay where there's also an anti-neutrino in that decay, but I just can't see how I can show that with the Clebsch-Gordan Coefficients.
I guess I look up the values for the neutron on the CG-table, but where to go from there?