CLAS physics database search results Measurement E151M1177 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.55 114 -0.8201 0.8245 0.067 0.75 90 0.1589 0.9774 0.0322 0.75 102 1.9156 1.0954 0.1432 0.75 210 -0.5004 0.7203 0.0473 0.85 90 -0.2817 0.801 0.0364 0.85 102 -0.0802 0.8635 0.0306 0.85 126 -1.1932 0.7436 0.0922 0.85 174 1.2878 0.9975 0.0988 0.85 186 0.9638 0.8373 0.0766 0.85 198 1.1582 0.7636 0.0898 0.85 210 -0.7483 0.6733 0.0624 0.85 222 -0.7424 0.7213 0.062 0.85 234 0.2922 0.7241 0.0368 0.95 186 -0.8974 0.738 0.0721 0.95 198 1.3217 1.0849 0.1012 0.95 210 1.0844 0.9127 0.0847 0.95 222 2.1439 1.0362 0.1595