CLAS physics database search results Measurement E151M1185 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 270 -0.7551 0.7612 0.0628 0.75 90 0.0947 0.9118 0.0308 0.75 102 2.0028 1.0716 0.1494 0.75 114 -1.5368 0.5975 0.1163 0.75 186 0.6168 0.9111 0.0542 0.75 198 -0.3831 0.7545 0.041 0.75 210 -2.0744 0.5185 0.1546 0.75 258 0.5881 0.8787 0.0524 0.75 270 -0.1867 0.8495 0.033 0.75 282 -0.2631 0.8513 0.0356 0.85 102 -0.5675 0.6775 0.0512 0.85 114 -0.9557 0.6593 0.076 0.85 126 -0.0131 0.8308 0.03 0.85 174 -0.4521 0.802 0.0446 0.85 186 0.8345 0.7945 0.068 0.85 198 -0.2654 0.6551 0.0357 0.85 210 -0.2132 0.6313 0.0338 0.85 222 -0.3878 0.7705 0.0413 0.85 270 -0.4226 0.8024 0.0431