CLAS physics database search results Measurement E151M799 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.85 102 0.2018 0.7005 0.0328 0.85 222 0.3527 0.82 0.0379 0.85 258 0.0521 0.7187 0.0302 0.85 306 -0.8942 0.5353 0.0659 0.95 270 -0.2057 0.8594 0.0329 0.95 294 0.7382 0.9718 0.057 0.65 102 1.1341 1.2249 0.1089 0.75 102 -0.9571 1.1435 0.0933 0.75 270 1.0323 1.0852 0.0999 0.85 258 -2.2815 0.8386 0.2127 0.85 270 -2.1271 0.8745 0.1986 0.85 282 0.2984 1.0829 0.0407 0.85 294 0.6122 1.009 0.064 0.95 282 -2.6169 2.8462 0.2434