CLAS physics database search results Measurement E151M1196 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 282 -0.7291 0.7556 0.0612 0.75 114 0.7865 1.0318 0.0648 0.75 186 0.7164 1.049 0.0603 0.75 270 -0.0145 0.8653 0.03 0.85 102 0.7164 0.8802 0.0603 0.85 114 0.486 0.7911 0.0465 0.85 126 -0.4134 0.7229 0.0426 0.85 138 -0.563 0.8999 0.0509 0.85 186 0.5598 0.7376 0.0507 0.85 198 -0.3033 0.697 0.0373 0.85 210 0.5199 0.7317 0.0484 0.85 222 -0.5132 0.7425 0.048