Theoretical aspects of scalar meson production in pp, pn and dd interactions

At COSY-Juelich an experimental program on the study of near-threshold a0/f0 production in pp, pn, pd and dd interactions has been started with the ANKE spectrometer. Recently, first results on the reaction pp → dK+K0 near threshold have become available at an energy excess of Q = 46 MeV. The future experimental study of the charge-symmetry breaking (CSB) a0 - f0 mixing will be extremely important to better understand the nature of the lightest scalar mesons a0(980) and f0(980). The reaction dd → αf0(I = 0) → αa00(I = 1) → α(π0η) seems to be most promising for the extraction of the CSB effects, since the initial deuterons and the α particle in the final state have isospin I = 0 (''isospin filter''). The primary dd → αf0 → αK+K- reaction is planned to be measured with ANKE. It will be ideal testing ground for the later measurements of the isospin violating process with WASA, which is accompanied by a smaller cross section. (orig.)