CLAS physics database search results Measurement E151M2135 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.75 294 -0.083 1.0119 0.031 0.85 102 -2.3915 1.1364 0.2218 0.85 114 -3.8087 3.8087 0.3513 0.85 234 -0.42 1.2839 0.0489 0.65 114 1.2983 0.7845 0.0896 0.75 282 0.079 0.745 0.0304 0.85 102 -2.6415 2.6415 0.1744 0.85 114 -0.2186 0.8127 0.0332 0.85 210 0.9081 1.0022 0.0663 0.85 234 0.1727 0.8809 0.032