CLAS physics database search results Measurement E151M559 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 258 -0.4463 0.6445 0.0406 0.75 90 -0.1354 0.5955 0.0311 0.75 102 -0.2065 0.6337 0.0326 0.75 246 -0.2503 0.675 0.0337 0.75 258 -0.4563 0.6373 0.041 0.75 282 0.0544 0.6544 0.0302 0.85 102 -0.3388 0.582 0.0365 0.85 114 0.7067 0.6716 0.0526 0.85 126 0.0908 0.6944 0.0305 0.85 210 -0.13 0.6795 0.031 0.85 234 0.2171 0.6946 0.0328 0.85 246 0.0101 0.5714 0.03 0.85 258 0.3393 0.6258 0.0365 0.85 270 1.3973 0.6991 0.0906 0.85 282 -0.2703 0.6081 0.0343 0.85 294 -0.5066 0.5571 0.0431 0.95 246 -0.6123 0.5299 0.048 0.95 270 0.3848 0.657 0.0381 0.95 282 -1.0764 0.3998 0.0724 0.95 294 -0.3956 0.5028 0.0385 0.95 306 -0.4772 0.3939 0.0419