Quark condensate effects on charmonium-pion scattering

TheJ/ψπ → -DD*,-DD,-D*D* and -DD* cross-sections as a function of √s are evaluated in a QCD sum rule calculation. We study the Borel sum rule for the four point function involving pseudoscalar and vector meson currents, up to dimension four in the operator product expansion. We find that our results are close to those obtained with quark exchange models. We also find that the quark condensate gives the main nonperturbative contribution to the cross-section.