CLAS physics database search results Measurement E151M1662 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.65 150 -0.642 1.2737 0.0479 0.65 222 0.5595 1.1374 0.0443 0.65 234 -0.7883 0.9793 0.0548 0.75 222 -1.3881 0.8623 0.0861 0.85 222 -0.1487 1.0801 0.0312 0.35 42 -0.7948 0.8855 0.0563 0.75 222 0.9046 0.8198 0.062 0.85 150 -0.1447 0.9248 0.0312 0.85 234 0.0042 0.816 0.03