CLAS physics database search results Measurement E151M1169 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.85 78 -1.4559 0.6077 0.1106 0.85 90 -0.4662 0.832 0.0454 0.85 102 0.736 1.0164 0.0616 0.85 186 1.8371 1.0968 0.1376 0.85 198 -0.2986 0.9169 0.0371 0.95 234 0.1118 0.809 0.0311 0.95 246 -0.3423 0.6568 0.0391 0.95 258 -1.1023 0.6611 0.086