We study the anomalously large rates of some hadronic transitions observed in heavy quarkonia using a constituent quark model that has been successful in describing meson and baryon phenomenology. QCD multipole expansion (QCDME) is used to describe the hadronic transitions. The hybrid intermediate states needed in the QCDME method are calculated in a natural, parameter-free extension of our constituent quark model based on the quark confining string scheme. Some of the anomalies are explained due to the presence of a hybrid state with a mass near the one of the decaying resonance, whereas others are justified by the presence of molecular components in the wave function. Certain unexpected results are pointed out.

• Received 13 October 2014

DOI:https://doi.org/10.1103/PhysRevD.91.014002