Close-to-Threshold Meson Production at COSY-11

Abstract

Meson production at threshold in the hadron-hadron interaction began in the fifties when sufficient energies of accelerated protons were available. A strong interdependence between developments in accelerator physics, detector performance and theoretical understanding led to a unique vivid field of physics. With the advent of the new cooler rings the field entered a new domain of precision.The analysis of these new data permits a more fundamental consideration and a quantitative comparison of the production processes for different mesons in the few-body final states. The interpretation of the data takes advantage of the fact that production reactions close to threshold are characterized by only a few degrees of freedom between a well defined combination of initial and exit channels. Deviations from predictions of one-meson-exchange models are indications of new physics. In future, precision data on differential cross sections, isospin and spin observables will test theoretical models.