CLAS physics database search results Measurement E151M1404 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.35 42 0.3077 0.7803 0.0459 0.35 54 -0.9394 0.7854 0.1101 0.45 42 -1.0405 0.7851 0.1211 0.45 54 0.4984 0.7042 0.0637 0.45 246 0.4624 0.853 0.0602 0.55 210 -0.4798 0.8384 0.0619 0.55 234 -1.2306 0.7813 0.142 0.65 222 -0.0472 0.7459 0.0305 0.65 234 -0.9395 0.774 0.1101 0.65 246 -0.007 0.6624 0.03 0.75 222 -0.0151 0.7404 0.03 0.75 234 -0.6306 0.6274 0.0772 0.75 246 0.1496 0.6964 0.0344 0.85 222 0.5735 0.7568 0.0713 0.85 234 -1.0066 0.6755 0.1174