ABSTRACT
It has been pointed out that among the multitude of resonances which have been discovered recently, can be arranged as a decuplet with one member still missing. The particle, Hyperon, is predicted to be a negatively charged isotopic singlet with strangeness minus three. The 10-dimensional representation of the group SU3 can be identified with just such a decuplet. Consequently, the existence of the Hyperon- has been cited as a crucial test of the theory of unitary symmetry of strong interactions. The mass is predicted by the Gell-Mann-Okubo mass formula to be about 1680 MeV/c2. The chapter presents the observation of an event which one believes to be an example of the production and decay of a particle. From measurements of the electron momenta and angles, one can determine that the effective mass of the two gamma rays is consistent with decay.
