CLAS physics database search results Measurement E151M1925 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.65 126 -0.5851 0.684 0.0464 0.75 222 -1.3826 0.6164 0.089 0.75 234 -0.9849 0.5845 0.0668 0.75 282 -0.2617 0.5752 0.0339 0.85 102 -0.6196 0.7869 0.0481 0.85 114 0.1996 0.6967 0.0323 0.85 198 -0.5804 0.7025 0.0462 0.85 210 -0.7928 0.5488 0.0566 0.85 222 0.9082 0.6143 0.0627