Chiral symmetry and charmonium decays to two pseudoscalars

We apply hard pion Chiral Perturbation Theory to charmonium decays to ππ, KK and ηη. We first discuss why we expect to be able to provide results for the chiral logarithms in χc0 and χc2 decays to two pseudoscalars while for the decays from J/ψ, ψ(nS) and χc1 no simple prediction is possible. The leading chiral logarithm turns out to be absent for χc0, χc2 → PP. This result is true for all fully chiral singlet states of spin zero and two.