CLAS physics database search results Measurement E159M667 E1-6 V. Burkert 2001 psi(pi+) dsigma/dpsi_pip Data errors deg mcb/rad mcb/rad 30 0.104123 0.0229601 90 0.0761194 0.017134 150 0.149266 0.0239277 210 0.104225 0.018627 270 0.105468 0.0199014 330 0.0717728 0.0150435