[UPSC CSE 2000] Particle Physics (Q312, 20M)

Which of the following reactions are allowed? What are the conservation laws violated by the rest ? Classify the particles (fermions / bosons. mesons / baryons, leptons/ hadrons) involved and the type of interactions in the case of the allowed ones. (i) \Sigma^0 \rightarrow \pi^+ + \pi^- (ii) \pi^- + p \rightarrow n + \pi^0 (iii) \pi^+ + p \rightarrow \pi^+ + p + \pi^- + \pi^0 (iv) \pi^0 \rightarrow \gamma + \gamma