CLAS physics database search results Measurement E159M990 E1-6 V. Burkert 2001 psi(pi-) dsigma/dpsi_pim Stat. error deg mcb/rad mcb/rad 30 0.23645 0.0402891 90 0.274704 0.0457649 150 0.360216 0.0643563 210 0.291722 0.0490377 270 0.306956 0.04861 330 0.232144 0.0450766