CLAS physics database search results Measurement E151M606 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 126 0.1555 0.7788 0.0315 0.65 258 1.1131 0.7415 0.0744 0.75 102 -0.0182 0.7214 0.03 0.75 246 -0.3681 0.6575 0.0375 0.85 66 0.5784 0.7623 0.0464 0.85 270 -0.2862 0.603 0.0347 0.95 258 0.8301 0.6796 0.059