CLAS physics database search results Measurement E151M1899 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.65 126 1.2919 0.7737 0.0838 0.65 234 -0.7902 0.822 0.0565 0.65 294 0.8711 0.7825 0.0607 0.75 222 -1.0691 0.7342 0.0714 0.75 234 -0.8019 0.7885 0.0571 0.85 102 -0.3455 0.8047 0.0366 0.85 114 1.1387 0.8518 0.0752 0.85 210 -1.3411 0.811 0.0866 0.85 222 -0.5493 0.813 0.0448 0.85 234 0.0333 0.9295 0.0301 0.95 114 -0.375 0.8301 0.0376 0.95 246 0.4707 0.802 0.0414