CLAS physics database search results Measurement E151M923 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 138 -1.8265 1.6989 0.1712 0.75 222 1.8996 1.9395 0.1779 0.75 282 -0.6144 1.5081 0.0642 0.85 114 0.6708 2.2931 0.0688 0.85 210 3.781 1.8826 0.3502 0.65 282 0.0944 0.5738 0.0306 0.75 270 0.1495 0.5912 0.0316 0.75 282 -0.2954 0.543 0.0357 0.85 114 0.6312 0.7342 0.0511 0.85 234 1.3992 0.7229 0.0966