CLAS physics database search results Measurement E151M690 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.55 222 0.9867 0.7775 0.0674 0.65 126 -0.0469 0.6763 0.0301 0.65 138 -0.9447 0.5902 0.0651 0.65 222 0.2085 0.6809 0.0326 0.65 294 0.3369 0.6411 0.0364 0.75 66 -0.3937 0.6626 0.0385 0.75 138 -1.3874 0.5391 0.09 0.75 198 -0.4209 0.6639 0.0395 0.75 210 -0.2339 0.6998 0.0332 0.75 222 0.1813 0.6762 0.032 0.75 234 -0.0063 0.5705 0.03 0.75 282 1.2439 0.6781 0.0818 0.85 102 1.6305 0.7133 0.1041 0.85 234 -0.136 0.5528 0.0311 0.95 234 -0.4987 0.5214 0.0428