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Radiative Decay of the ψ(2S) into Two Pseudoscalar Mesons

Radiative decays of the radially excited charmonium resonance, ψ(2S), into ππ, K Kbar and ηηfinal states have been measured in a sample of 3.96 * 10^6 ψ(2S) events collected by the BES collaboration. The branching ratios B(ψ(2S) -> γf_{2}(1270)) = (2.27 +- 0.26 +- 0.39) * 10^{-4} and B(ψ(2S) -> γf_0(1710)) * B(f_0(1710) -> K^+ K^-) = (5.59 +- 1.12 +- 0.93) * 10^{-5} are obtained. When compared to the corresponding radiative J/ψdecays, the observed ψ(2S) radiative decay rates into γf_2(1270) and γf_0(1710) are consistent with the 15% rule.