CLAS physics database search results Measurement E151M1147 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 210 0.8516 0.984 0.0691 0.75 198 -0.884 0.8071 0.0712 0.75 210 1.3031 0.8977 0.0999 0.75 222 0.3192 0.9114 0.038 0.75 282 0.0117 0.8797 0.03 0.85 90 -1.1392 0.6837 0.0885 0.85 102 0.3915 0.9554 0.0415 0.85 114 1.3361 0.9029 0.1022 0.85 126 0.8463 1.018 0.0687 0.85 186 1.6151 1.0173 0.1218 0.85 210 -1.7218 0.5547 0.1294 0.85 222 -0.4761 0.8482 0.0459 0.85 234 0.7991 0.9129 0.0657