CLAS physics database search results Measurement E151M1191 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.85 90 0.3727 0.8875 0.0405 0.85 102 0.9599 1.0115 0.0763 0.85 186 2.7776 1.2469 0.2052 0.85 198 0.4938 0.8969 0.0469 0.85 210 -0.7377 0.7272 0.0617 0.85 222 0.2205 0.8426 0.0341 0.85 234 1.2729 1.023 0.0978 0.95 210 0.6953 0.9383 0.059 0.95 222 0.6806 0.8812 0.0581