- and Vector-Meson Production in Hadron-Nucleus Reactions

The production and decay of vector mesons (ρ, ω) in pA reactions at COSY energies is studied with particular emphasis on their in-medium spectral functions. It is explored within transport calculations, if hadronic in-medium decays like π⁺π^- or π⁰γ might provide complementary information to their dilepton (e⁺e^-) decays. Whereas the π⁺π^- signal from the ρ-meson is found to be strongly distorted by pion rescattering, the ω-meson Dalitz decay to π⁰γ appears promising even for more heavy nuclei. The perspectives of scalar meson (f₀, a₀) production in pp reactions are investigated within a boson-exchange model indicating that the f₀-meson is hard to detected in these collisions in the Kbar K or ππ decay channels whereas the channels pp-> pna_0⁺ and pp-> da_0⁺ look very promising.