CLAS physics database search results Measurement E151M1199 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.75 210 0.4053 1.035 0.0422 0.85 102 1.4606 1.0167 0.1109 0.85 114 -0.4284 0.8203 0.0434 0.85 126 0.636 1.0309 0.0553 0.85 174 0.1288 0.989 0.0314 0.85 198 -0.7215 0.7639 0.0607 0.85 210 -0.0163 0.8441 0.03 0.85 222 -0.8213 0.7891 0.0671