Hi everyone, i was reading the article of Cristenson,Cronin,Fitch and Turlay of 1964, the one that discovered CP violation in the system of neutral K mesons. There is one point in it that i don't get it. They say "the angle should be zero for two body decay and is, in general, different from zero for three body decay". Based to what i know, it must be conserved the longitudinal and transversal component of the momentum, so if the boost is high, the angle should be small. It's this the right explanation for the very small angle of decay observed? I really appreciate any help you can provide.