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 We calculate the next-to-leading-order corrections to the perturbative QCD calculation of the decay J/psi arrow pi+pi- that cannot be factorized into either initial or final state wave functions. When using either the asymptotic or Chernyak-Zhitnitsky distribution amplitudes for the pion we find that these corrections are small (approximately 5%). Since the leading process is proportional to F squared subscript pi (M 2sj), we suggest that the pion form factor at a large timelike Q2 can be extracted from the measured decay rate of charmonium. Normalizing to the corresponding leptonic decay channels, we thus obtain that M2J F pi (M J) is nearly equal to 0.9, approximately a factor of 2 larger than what might have been commonly expected.
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