11.3 Exercise 12

Express the $\beta$ decays $n \rightarrow p + e^{−} + \overset{−}{\nu}$ and $p \rightarrow n + e^{+} + \nu$ in terms of $\beta$ decays of quarks. Check to see that the conservation laws for charge, lepton number, and baryon number are satisfied by the quark $\beta$ decays.