CLAS physics database search results Measurement E151M648 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 114 -0.7746 0.6971 0.0561 0.65 126 -1.5066 0.6282 0.0969 0.65 222 1.2022 0.8543 0.0794 0.65 294 1.0132 0.7764 0.0689 0.75 102 -0.6493 0.7333 0.0498 0.75 126 0.8283 0.7826 0.0589 0.75 222 -0.2878 0.6587 0.0348 0.75 246 0.432 0.7321 0.04 0.85 222 -0.2437 0.5895 0.0335 0.85 234 1.1548 0.6252 0.0767 0.85 246 1.4934 0.7289 0.0961 0.85 258 0.2505 0.6431 0.0337 0.85 270 -0.1437 0.7481 0.0313 0.95 210 0.9386 0.7004 0.0648 0.95 246 0.8901 0.6351 0.0622 0.95 270 0.0077 0.599 0.03