CLAS physics database search results Measurement E151M2890 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LU Stat. error Syst. error degrees 0.65 222 0.0882 0.2636 0.0301 0.75 162 0.0653 0.2713 0.03 0.75 234 -0.1111 0.2806 0.0301 0.75 246 0.3603 0.2566 0.0309 0.85 246 -0.0159 0.2597 0.03 0.55 222 -0.7489 0.1795 0.0335 0.85 222 0.2221 0.3891 0.0303 0.85 234 -0.1022 0.3206 0.0301 0.85 246 0.4427 0.314 0.0313