CLAS physics database search results Measurement E151M1160 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 138 3.8492 3.8492 0.2829 0.75 210 2.4769 0.9696 0.1835 0.75 222 0.0352 0.8589 0.0301 0.85 102 -0.4894 0.7785 0.0467 0.85 126 1.3662 1.0645 0.1043 0.85 174 -1.562 0.7119 0.118 0.85 186 -0.1321 0.7941 0.0315 0.85 198 -0.6311 0.7208 0.055 0.85 210 -0.4114 0.6999 0.0425 0.85 222 -0.3994 0.6998 0.0419