CLAS physics database search results Measurement E151M3158 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LU Stat. error Syst. error degrees 0.75 210 0.3405 0.2526 0.0308 0.75 222 0.2855 0.2629 0.0305 0.75 270 0.2178 0.2547 0.0303 0.85 198 -0.5806 0.2041 0.0322 0.85 210 0.0071 0.2742 0.03 0.85 222 -0.1095 0.253 0.0301