CLAS physics database search results Measurement E151M1669 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.55 222 -1.5938 0.6668 0.099 0.65 150 0.0345 0.7945 0.0301 0.65 222 -0.3118 0.7992 0.0353 0.75 234 -1.3858 0.7598 0.0883 0.85 138 -0.087 0.9177 0.0305 0.85 150 -1.1154 0.9649 0.0733 0.85 222 -0.1225 0.9186 0.0309 0.85 234 -1.4904 0.8662 0.0942 0.85 246 0.2329 0.8742 0.0331 0.65 234 -0.1824 1.2048 0.0318 0.65 246 -1.3252 1.0865 0.0827 0.75 222 1.6413 0.9072 0.1 0.75 234 -0.6778 1.2443 0.0495 0.85 234 2.4894 2.4894 0.1478