CLAS physics database search results Measurement E151M678 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.45 270 0.9503 0.7788 0.0654 0.55 126 0.4717 0.8316 0.0416 0.55 270 -0.483 0.748 0.0421 0.65 114 -0.5686 0.6847 0.0459 0.65 222 1.8632 0.7602 0.1178 0.65 294 1.1857 0.7307 0.0785 0.75 126 0.485 0.8191 0.0422 0.75 210 -0.1473 0.7218 0.0313 0.75 222 0.2275 0.8027 0.0331 0.75 234 1.1798 0.6818 0.0781 0.85 90 0.2022 0.7574 0.0324 0.85 114 -0.1622 0.736 0.0316 0.85 210 0.1704 0.738 0.0318 0.85 222 0.2673 0.7929 0.0342 0.85 234 1.3992 0.8516 0.0907 0.85 258 -0.0692 0.7798 0.0303