CLAS physics database search results Measurement E151M1664 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.45 42 0.6967 0.782 0.0511 0.65 222 -1.654 0.9025 0.1036 0.85 234 -0.7664 0.8594 0.0549 0.45 222 -0.8477 1.1905 0.0577 0.55 222 -1.9365 0.8248 0.1165 0.55 234 -1.9562 0.9154 0.1176 0.75 234 0.2298 1.1044 0.0328 0.85 138 -2.4163 0.6405 0.1437 0.85 222 0.6647 1.0689 0.0489 0.85 234 -1.0676 1.0943 0.0689