CLAS physics database search results Measurement E151M9 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Data errors Systematic errors degrees 0.45 282 -0.0204 0.4466 0.0301 0.55 258 -0.1125 0.4003 0.0326 0.55 270 0.2269 0.3761 0.0396 0.55 282 -0.7785 0.3444 0.0935 0.65 258 -0.439 0.3447 0.0583 0.65 270 -0.0034 0.2842 0.03 0.75 246 -1.036 0.3499 0.1216 0.75 258 0.1602 0.4087 0.0351 0.75 270 -0.0723 0.3785 0.0311 0.85 138 1.0086 0.5441 0.1186 0.85 150 0.7962 0.4231 0.0954 0.85 162 -0.0223 0.4465 0.0301 0.85 174 -0.373 0.3061 0.052 0.85 186 0.2089 0.3485 0.0383 0.85 198 -0.1159 0.3131 0.0328 0.85 210 -0.0053 0.437 0.03 0.85 222 -0.2973 0.4061 0.0452 0.95 174 0.1896 0.4183 0.0369