[UPSC CSE 2016] Particle Physics (Q261, 10+5+5+5=25M)

Explain the various leptonic family members. What is leptonic number conservation? Based on this conservation law, state whether the following reactions are possible or not:

(i) \pi^- \to \mu^- \bar{\nu}_\tau

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