CLAS physics database search results Measurement E151M2146 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.85 102 2.5964 2.3819 0.2405 0.85 126 -2.8621 2.4785 0.2647 0.85 210 0.637 2.2643 0.0658 0.65 294 -0.6662 0.6184 0.0527 0.85 114 -2.1172 0.7219 0.141 0.85 234 -1.2426 0.7175 0.0862