CLAS physics database search results Measurement E151M197 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Data errors Systematic errors degrees 0.35 42 0.9239 0.6259 0.1093 0.35 54 0.6891 0.6245 0.0839 0.35 66 0.3725 0.7118 0.0519 0.45 42 -0.4774 0.6682 0.062 0.45 54 0.353 0.614 0.0501 0.45 210 0.0016 0.6457 0.03 0.45 222 0.4785 0.6254 0.0622 0.45 234 -0.4139 0.5807 0.0558 0.55 42 -0.7125 0.5684 0.0864 0.55 210 0.3918 0.5788 0.0537 0.55 222 1.2445 0.6502 0.1447 0.55 234 -0.002 0.471 0.03 0.55 246 0.3203 0.6405 0.0472 0.65 222 0.3188 0.5184 0.0471 0.65 234 0.3426 0.4753 0.0492 0.65 246 0.3762 0.6446 0.0523 0.75 222 -0.2185 0.4582 0.039 0.75 234 -0.2011 0.5555 0.0377 0.85 222 -0.1523 0.5969 0.0346