CLAS physics database search results Measurement E151M2151 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.75 270 -0.8116 0.7494 0.0804 0.75 282 -0.2345 0.5098 0.0363 0.85 114 -1.4827 0.9969 0.1395 0.85 126 0.9336 0.7808 0.0677 0.85 210 -1.9522 0.793 0.1305