CLAS physics database search results Measurement E151M2367 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.75 78 1.5898 0.9618 0.1191 0.85 66 2.4102 0.7308 0.1773 0.85 78 1.2835 0.8022 0.0978 0.85 222 -0.5261 0.9901 0.0485 0.85 246 -0.9775 0.8896 0.077 0.95 198 -0.5912 0.8339 0.0523 0.95 210 -0.1603 1.0186 0.0322 0.95 222 -0.242 0.8145 0.0348 0.95 246 1.0252 0.7647 0.0802 0.95 258 0.114 0.8397 0.0311 0.95 270 1.0379 0.9169 0.081 0.95 282 -1.5217 0.8148 0.1143 0.95 294 -1.0914 0.7372 0.0846