[UPSC CSE 2022] Particle Physics (Q236, 15M)

Which of the following decays are allowed and which are forbidden? If the decay is allowed, state which interaction is responsible. If it is forbidden, state which conservation law its occurrence would violate.

(i) n\to p+e^{-}+\bar{\nu}_e

(ii) \Lambda^{0}\to\pi^{+}+\pi^{-}

(iii) \pi^{-}\to e^{-}

(iv) \pi^{0}\to e^{-}e^{+}+\nu_e+\bar{\nu}_e

(v) \pi^{+}\to e^{+}e^{-}+\mu^{+}+\nu