Chapter 11, Problem 35P

Which of the following decays cannot occur because die law of conservation of lepton number is violated?

(a) $n\to \text{p}+e^{-}$     (e) ${\pi }^{-}\to e^{-}+{\bar{v}}_e$

(b) ${\mu }^{+}\to e^{+}+v_e$    (f) ${\mu }^{-}\to e^{-}+{\bar{v}}_e+v_{\mu }$

(c) ${\pi }^{+}\to e^{+}+v_e+{\bar{v}}_{\mu }$   (g) ${\Lambda }^0\to {\pi }^{-}+\text{p}$

(d) $\text{p}\to n+e^{+}+v_e$     (h) $K^{+}\to {\mu }^{+}+v_{\mu }$