CLAS physics database search results Measurement E151M2038 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.75 234 0.2892 1.0336 0.0401 0.85 246 -1.1023 1.2658 0.1057 0.65 234 1.5319 0.8792 0.1041 0.65 246 -0.343 0.9016 0.0374 0.75 114 -0.9905 0.8807 0.0711 0.75 126 0.1309 0.8295 0.0312 0.75 138 -1.1804 0.9474 0.0824 0.75 222 -0.4172 1.0077 0.0405 0.75 234 0.5156 0.7986 0.045 0.75 246 -1.7424 0.7837 0.1172 0.85 234 0.1209 1.0051 0.031