CLAS physics database search results Measurement E216M499 CLAS12 Run Group A Krishna Chandra 2018 psi(pi-) dsigma/dpsi_pim Stat. error Syst. error deg mcbn/rad mcbn/rad mcbn/rad 18 0.242591 0.00988906 0.03818521 54 0.2684 0.0146063 0.02462765 90 0.293384 0.0105935 0.02439085 126 0.366642 0.0103194 0.02694752 162 0.438552 0.00971303 0.03171329 198 0.447547 0.0105801 0.03379618 234 0.346643 0.0100683 0.02803468 270 0.333424 0.0171265 0.02654743 306 0.267805 0.0117796 0.02412251 342 0.252653 0.0186987 0.02750409