CLAS physics database search results Measurement E151M310 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Data errors Systematic errors degrees 0.55 234 -0.0786 0.4972 0.0317 0.65 138 0.3461 1.0391 0.0365 0.65 150 0.004 1.0179 0.03 0.65 222 0.0307 0.4979 0.0355 0.65 234 0.4351 0.4387 0.0434 0.65 246 -0.0294 0.4012 0.0805 0.75 150 -0.734 0.6437 0.0545 0.75 222 0.1475 0.5835 0.0314 0.75 234 -0.0792 0.4157 0.0304 0.85 210 -0.3987 0.7586 0.0384 0.85 222 0.7463 1.0701 0.054 0.85 234 -0.0208 0.7565 0.03 0.85 246 -0.6992 0.5627 0.0517 0.75 246 1.1027 0.5058 0.0746 0.85 222 0.5743 0.5906 0.0465 0.85 234 1.4878 0.59 0.0969 0.85 246 0.1818 0.5828 0.032