CLAS physics database search results Measurement E151M1179 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.75 222 0.0402 0.9656 0.0301 0.85 78 -1.1572 0.7412 0.0897 0.85 90 -1.2498 0.6146 0.0962 0.85 102 -0.5429 0.7701 0.0497 0.85 186 0.0708 0.9869 0.0304 0.85 198 0.5189 0.9593 0.0484 0.85 210 1.3745 0.958 0.1048 0.85 222 -1.1166 0.6719 0.0869 0.85 234 -0.6691 0.701 0.0574 0.95 198 0.2171 0.8136 0.0339 0.95 210 -0.7098 0.7471 0.0599 0.95 222 0.8507 0.8605 0.069 0.95 234 0.0222 0.8331 0.03