CLAS physics database search results Measurement E151M182 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Data errors Systematic errors degrees 0.35 42 -0.3941 0.6545 0.0539 0.35 54 -0.9264 0.5971 0.1096 0.45 42 -0.0467 0.6733 0.0305 0.45 54 -0.2684 0.6092 0.0428 0.45 246 1.7425 0.7429 0.2005 0.55 210 0.7377 0.7646 0.0891 0.55 234 -0.9418 0.6397 0.1113 0.65 222 1.1143 0.6789 0.1303 0.65 234 -0.1041 0.6818 0.0323 0.65 246 -0.832 0.524 0.0993 0.75 222 -0.5381 0.6077 0.0682 0.75 234 0.7836 0.5864 0.0941 0.75 246 0.2901 0.626 0.0446 0.85 222 0.9003 0.7039 0.1067 0.85 234 1.0669 0.6615 0.125