CLAS physics database search results Measurement E151M2378 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.85 78 -0.7494 0.9301 0.0621 0.85 198 -1.0546 0.8651 0.0821 0.85 210 -0.9985 1.0501 0.0784 0.85 222 0.2195 0.9833 0.034 0.85 234 0.6634 0.8044 0.0567 0.85 246 0.813 0.9247 0.0661 0.85 258 -1.9049 0.814 0.1414 0.95 162 -1.3606 0.9632 0.1031 0.95 186 1.174 0.9119 0.0903 0.95 198 -1.6797 0.813 0.1254 0.95 210 0.0617 0.9849 0.0303 0.95 222 1.7158 0.7122 0.128 0.95 234 -0.6165 0.7122 0.0538 0.95 246 -0.8377 0.9856 0.0677 0.95 258 0.0846 0.7902 0.0306