RESCATTERING EFFECTS IN 3-PARTICLE STATES AND THE SCHMID THEOREM

We discuss effects of anomalous singularities in three-meson productio n amplitudes which are caused by the triangle diagrams with resonance production in the intermediate state followed by the rescattering of o utgoing particles. We show that the Schmid theorem [C. Schmid, Phys. R ev. 154 (1967) 1363] is not valid when the amplitude of the rescatteri ng particles has several open channels. In this case the irregularitie s related to anomalous singularities appear not only in the three-part icle Dalitz-plot but in the two-particle distributions as well. Exampl es of the processes p ($) over bar p (at rest) --> (three mesons) are discussed.