CLAS physics database search results Measurement E151M1884 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.65 114 -0.0005 0.844 0.03 0.65 234 -0.5752 0.9313 0.046 0.65 294 -0.6858 0.8034 0.0513 0.75 114 -0.3862 0.9029 0.038 0.75 222 0.6085 0.7121 0.0475 0.75 234 -0.2491 0.9248 0.0336 0.75 246 1.8385 0.7375 0.1154 0.85 102 1.2009 0.8084 0.0787 0.85 114 -0.4399 0.961 0.0401 0.85 222 0.432 0.7395 0.0398 0.85 234 0.3848 0.8518 0.038 0.85 246 -0.1448 0.8937 0.0313 0.95 222 0.2059 0.7354 0.0325 0.95 246 -0.3381 0.6517 0.0363 0.95 258 0.1008 0.6834 0.0306