CLAS physics database search results Measurement E151M677 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 126 -0.1135 0.7122 0.0308 0.65 234 -0.6126 0.6633 0.048 0.65 294 0.0253 0.6927 0.03 0.75 222 -0.6738 0.6094 0.051 0.75 234 0.3243 0.7443 0.036 0.85 102 -0.6072 0.6315 0.0477 0.85 114 -0.9544 0.6509 0.0656 0.85 210 0.6784 0.8155 0.0512 0.85 222 0.2899 0.7362 0.0348 0.85 234 -0.3376 0.7483 0.0364 0.95 114 -0.6833 0.6301 0.0514 0.95 246 0.7691 0.776 0.0558