CLAS physics database search results Measurement E151M1455 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.75 258 1.1859 0.6349 0.0771 0.65 246 0.3245 0.8597 0.0354 0.65 258 -0.8418 0.6298 0.0574 0.75 246 -0.4305 0.7639 0.0391 0.75 258 1.7139 1.7139 0.1041