CLAS physics database search results Measurement E151M890 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.85 234 0.5774 0.7254 0.0612 0.85 246 0.7648 0.7828 0.0767 0.95 234 7.0545 7.0545 0.6518 0.95 258 -0.8441 2.0092 0.0835 0.65 126 -0.7011 0.7519 0.0549 0.75 126 -1.1746 0.7077 0.0827 0.85 90 -1.8383 0.5105 0.1243 0.85 222 0.4659 0.9042 0.0428 0.85 234 -0.123 0.7744 0.0311 0.85 246 0.2002 0.8158 0.0328 0.95 258 1.3892 1.3724 0.096