CLAS physics database search results Measurement E151M713 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.35 78 -0.4783 0.6561 0.0419 0.35 282 0.1848 0.7491 0.0321 0.65 198 0.2143 0.7121 0.0327 0.65 282 0.8073 0.733 0.0578 0.75 66 -0.0848 0.6066 0.0304 0.75 210 0.3968 0.6454 0.0386 0.75 270 -0.9101 0.4778 0.0632 0.75 282 -0.0442 0.7032 0.0301 0.85 114 -0.0081 0.5986 0.03 0.85 126 -0.0991 0.7228 0.0306 0.85 198 0.5972 0.7079 0.0473 0.85 222 0.265 0.6723 0.0341