The ωπ0-transient form factor within effective chiral Lagrangian approach

The ωπ0-transient form factor is explored within effective chiral Lagrangians, based on the extended Nambu-Jona-Lasinio model and incorporating a gauge-invariant vector dominance approach. It is shown that on the whole the experimental data can be described by the contribution of the virtual ρ-meson with many channel parametrization of the imaginary part of the propagator. The processes ω → π0 μ+ μ-, e+ e- → π0ω and τ- → ντ π-ω, connected with the ωπ0-transient for factor, have been analyzed. The theoretical results are in reasonable agreement with experimental data. The explanation of the observed discrepancies between theoretical results and experimental data goes beyond the effective chiral Lagrangian approach. (author). 22 refs, 5 figs, 4 tabs