Production of Heavy Unstable Particles in ap−pCollision

A hydrogen-filled diffusion cloud chamber was exposed to a 2.7-Bev proton beam. In a collection of 202 $p-p$ collisions, there was one event interpreted as the associated production of a hyperon and a $K$-meson, via the reaction $p+p\to {\Lambda }^{+}+K^{+}+n$.