CLAS physics database search results Measurement E151M3635 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LU Stat. error Syst. error degrees 0.85 90 -0.0263 0.2514 0.03 0.85 102 -0.1191 0.2655 0.0301 0.85 186 -0.014 0.2882 0.03 0.85 198 0.022 0.2464 0.03 0.85 210 -0.0285 0.2413 0.03 0.85 222 -0.221 0.2332 0.0303 0.85 234 -0.2235 0.2549 0.0303 0.95 210 -0.129 0.2666 0.0301 0.95 222 -0.0981 0.2551 0.0301