CLAS physics database search results Measurement E151M1198 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 282 -0.4384 0.8139 0.0439 0.75 102 0.1564 0.9696 0.0321 0.75 114 -0.4198 0.9022 0.0429 0.75 198 -0.1017 0.9345 0.0309 0.75 282 -0.3794 0.8524 0.0409 0.85 102 -0.2459 0.7279 0.035 0.85 114 0.6895 0.9449 0.0586 0.85 126 0.8238 1.0235 0.0673 0.85 174 0.6615 1.0425 0.0569 0.85 198 -1.3921 0.5772 0.1061 0.85 210 0.5278 0.8383 0.0489 0.85 222 0.1173 0.8164 0.0312