A V-type of event is observed in a bubble chamber. The curvature measurements on the two tracks show that their momenta are p+ = 1.670 GeV/c and p− = 0.408 GeV/c. The angle contained between the two tracks is θ = 15◦. It is obviously due to the decay of a neutral unstable particle. It is suspected that it is due to the decay (a) K0 → π+ + π− or (b) Λ → p + π− . Identify the neutral particle.
