Meson Widths and Form Factors at Intermediate Momentum Transfer in Non-Perturbative QCD

Abstract

Abstract A general method is proposed for the QCD based calculations of form factors at intermediate Q 2 and of the partial widths of the low-lying mesonic resonances. The basic idea is to use the QCD sum rules for the vertex functions and to saturate their Borel transform by the lowest mesonic states. With this method the pion electromagnetic form factor along with electromagnetic form factors of ϱ and A 1 mesons and transition form factors γπ →A 1 at 0.5≲ Q 2 ≲3 GeV 2 are calculated. The widths ϱ →2 π and A 1 → ϱπ are also determined. The results are in a good agreement with experiment.