CLAS physics database search results Measurement E151M841 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.75 90 0.8961 0.629 0.066 0.75 102 -0.9425 0.5569 0.0687 0.75 246 -0.0002 0.6902 0.03 0.85 234 -0.0137 0.7449 0.03 0.85 246 -1.1438 0.5918 0.0808 0.85 270 -0.5566 0.6299 0.0473 0.95 282 0.3769 1.0359 0.0389 0.65 114 -1.0804 1.0785 0.1041 0.75 246 1.4483 1.177 0.137 0.85 66 1.7143 1.4887 0.161 0.85 114 2.7484 1.6034 0.2554 0.85 258 0.06 1.1513 0.0305 0.85 282 -1.7239 0.9704 0.1619