CLAS physics database search results Measurement E151M2382 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.65 138 0.5885 1.248 0.0522 0.75 210 -0.4815 1.0612 0.046 0.75 222 -2.1671 0.8424 0.16 0.85 102 0.7439 0.9159 0.0617 0.85 126 -0.0533 1.112 0.0302 0.85 174 2.1267 0.8587 0.1571 0.85 186 -1.9462 0.8092 0.1443 0.85 198 -1.105 0.8875 0.0856 0.85 210 -0.8524 0.8532 0.0687 0.85 222 -1.3979 0.7936 0.1057