CLAS physics database search results Measurement E151M1901 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.65 114 -1.321 0.8458 0.0855 0.65 126 0.2831 0.9059 0.0346 0.65 210 -0.3127 1.0302 0.0355 0.65 294 0.0509 0.8747 0.0302 0.75 126 0.5867 0.9201 0.0465 0.75 138 -1.2309 0.9136 0.0804 0.75 234 1.0983 0.8677 0.073 0.75 246 1.0782 0.8878 0.0719 0.75 294 2.1296 0.6589 0.1325 0.85 90 -0.8005 0.9393 0.057 0.85 102 1.8171 0.6772 0.1141 0.85 222 0.966 0.7516 0.0658 0.85 234 -0.4488 0.7512 0.0405 0.85 246 0.1158 0.7643 0.0308 0.85 258 -0.3327 0.9136 0.0361 0.95 234 -0.3953 0.7792 0.0384 0.95 246 0.2 0.7536 0.0324