CLAS physics database search results Measurement E151M142 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Data errors Systematic errors degrees 0.55 246 -0.4381 0.7565 0.0582 0.55 258 -0.1539 0.7196 0.0347 0.65 234 -0.532 0.7172 0.0676 0.65 246 -0.56 0.6487 0.0704 0.65 258 0.1178 0.6905 0.0329 0.65 270 -0.6027 0.6699 0.0748 0.75 138 0.9262 0.9048 0.1096 0.75 174 -0.4688 0.8007 0.0612 0.75 222 -0.9458 0.7529 0.1117 0.75 246 -0.9748 0.5375 0.1149 0.75 258 0.0493 0.7441 0.0305 0.75 270 -0.908 0.5385 0.1076 0.75 282 -0.57 0.7257 0.0714 0.85 138 0.2403 0.9115 0.0406 0.85 234 -0.2353 0.7757 0.0402 0.85 246 0.0914 0.6817 0.0318 0.85 258 -0.5533 0.5197 0.0697 0.85 270 0.0562 0.5243 0.0307 0.85 282 1.0835 0.7413 0.1269 0.95 258 -0.4218 0.6005 0.0566