CLAS physics database search results Measurement E159M991 E1-6 V. Burkert 2001 psi(pi+) dsigma/dpsi_pip Data errors deg mcb/rad mcb/rad 30 0.259258 0.0504123 90 0.309075 0.0545517 150 0.265719 0.0436813 210 0.309961 0.0496003 270 0.310817 0.0536702 330 0.259157 0.0522996