INELASTIC FINAL-STATE INTERACTIONS AND NEAR-THRESHOLD SINGULARITIES

It is shown that non-monotonic energy variations can occur in the energy spectrum of particle a from a reaction of the type A + B → a + C + D in the neighborhood of the threshold for the reaction C + D → E + F. As an example, we analyze the spectrum of K mesons from the reaction N + N → Λ + N + K in the region of the energy of the Λ − N pair close to the threshold for the process Λ + N → Σ + N. For the process p + p → Λ + N + K we find the energy spectrum of the K mesons when the incident nucleons are unpolarized, and the polarization of the baryons when the incident nucleons are polarized.

We discuss the non-monotonic energy variations in the spectra of particles for some other reactions. In the Appendix we analyze the production of Y − K pairs in np collisions and discuss the case of a scalar K particle.