Hadronic and Electromagnetic Interactions of Quarkonia

We examine the hadronic interactions of quarkonia, focusing on the decays ψ(2S) → J/ψππ and Υ(2S) → Υ(1S)ππ. The leading gluonic operators in the multipole expansion are matched onto the chiral lagrangian with the coefficients fit to available data, both at tree-level and loop-level in the chiral expansion. A comparison is made with naive expectations loosely based on the large-Nc limit of QCD in an effort to determine the reliability of this limit for other observables, such as the binding of J/ψ to nuclei. Crossing symmetry is used to estimate the cross-section for inelastic πJ/ψ → πψ(2S) scattering, potentially relevant for heavy ion collisions. The radiative decays ψ(2S)→ J/ψπ+π−γ and Υ(2S)→ Υ(1S)π+π−γ are determined at tree-level in the chiral lagrangian. Measurement of such decays will provide a test of the multipole and chiral expansions. We briefly discuss decays from the Υ(3S) and also the contribution from π’s to the electromagnetic polarizability of quarkonia.