CLAS physics database search results Measurement E151M1383 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.55 246 -0.3073 0.813 0.0458 0.55 258 -0.2267 0.8864 0.0394 0.55 270 1.1334 0.8125 0.1313 0.65 150 1.6415 0.896 0.1876 0.65 222 -0.5616 0.9209 0.0701 0.65 234 -0.4454 0.8753 0.0585 0.65 246 1.0696 0.7519 0.1243 0.65 258 0.4987 0.6625 0.0637 0.65 270 0.2376 0.8095 0.0402 0.75 150 -1.7883 0.8898 0.2039 0.75 162 -0.5537 0.9875 0.0693 0.75 234 0.4088 0.7529 0.055 0.75 246 -0.1201 0.8205 0.0329 0.75 258 0.2664 0.7724 0.0425 0.75 270 0.9811 0.7841 0.1146 0.85 234 -0.2146 0.849 0.0385 0.85 246 -0.2786 0.7459 0.0434 0.85 258 0.0376 0.8138 0.0303 0.85 270 1.0534 0.7031 0.1225 0.85 282 1.5254 0.7349 0.1746