CLAS physics database search results Measurement E151M1512 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.65 222 0.4366 0.6994 0.0398 0.65 234 1.5768 0.5935 0.0992 0.65 246 -0.6381 0.6849 0.0486 0.75 138 -0.5927 0.7916 0.0465 0.75 222 0.6045 0.8031 0.047 0.75 234 -0.6089 0.6914 0.0472 0.75 246 -0.4427 0.7121 0.0401 0.85 234 0.6259 0.7451 0.048 0.85 246 0.5569 0.7759 0.0449 0.55 246 0.9022 1.1244 0.0604 0.65 234 1.0288 0.8093 0.0669 0.75 234 -1.6145 0.604 0.0986 0.75 246 1.064 0.8044 0.0688 0.85 234 0.7224 1.1515 0.0516