CLAS physics database search results Measurement E151M2377 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.75 78 0.9212 0.9079 0.0732 0.75 90 -0.4637 1.0605 0.0451 0.75 198 -0.8128 1.0497 0.0661 0.85 78 -1.7293 0.8188 0.1289 0.85 90 -0.5377 0.9808 0.0492 0.85 102 -1.0519 1.0271 0.082 0.85 186 -0.8445 0.993 0.0682 0.85 198 -1.6694 0.6601 0.1247 0.85 210 0.0071 0.8913 0.03 0.85 222 0.7966 0.8296 0.0651 0.85 234 0.7214 0.6996 0.0603 0.85 246 -0.2568 1.0477 0.0353 0.95 174 -0.0017 1.0237 0.03 0.95 186 -2.4295 0.7852 0.1787 0.95 198 1.4438 0.8387 0.1089 0.95 210 -0.8107 0.742 0.066 0.95 222 1.1858 0.8191 0.0911 0.95 234 1.8831 0.8965 0.1398 0.95 246 0.9086 0.7797 0.0724 0.95 258 -1.8622 0.691 0.1383 0.95 270 -0.2156 0.7707 0.0338