CLAS physics database search results Measurement E151M3093 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LU Stat. error Syst. error degrees 0.65 102 0.002 0.2806 0.03 0.75 234 -0.266 0.2732 0.0305 0.85 78 0.1508 0.2803 0.0302 0.85 246 -0.0525 0.2429 0.03 0.85 258 0.0417 0.2726 0.03 0.95 222 -0.1655 0.2598 0.0302 0.95 234 0.0171 0.2783 0.03