Abstract

Since weakly decaying particles are their own polarimeters, reactions like $\eta _c \to \Lambda \bar \Lambda , \psi \to \Lambda \bar \Lambda ,e^ + e^ - \to \mu ^ + \mu ^ -$ , etc. are interesting for testing the non-locality of quantum mechanical predictions. Although such reactions, in principle, do not exclude all classes of hidden variable theories, they can be used to complement current experiments with external polarimeters. The reaction $\eta _c \to \Lambda \bar \Lambda \to \pi ^ - p\pi ^{ + - } \bar p$ is conceptually the simplest and most useful as agedanken experiment, although it has not yet been seen experimentally. The reaction $e^ + e^ - \to \Lambda \bar \Lambda \to \pi ^ - p\pi ^ + \bar p$ near threshold or at the φ resonance can be used for essentially the same test. This is feasible with presently available data and would be the first EPR experiment involving weak interactions