CLAS physics database search results Measurement E151M2401 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.75 222 -0.1756 1.1157 0.0326 0.85 78 -0.5711 1.0447 0.0511 0.85 90 -1.4791 0.855 0.1114 0.85 102 -0.4239 0.9655 0.043 0.85 186 -0.9616 1.0915 0.0759 0.85 198 1.2751 0.9834 0.0972 0.85 210 0.6493 0.9985 0.0558 0.85 222 0.9678 0.9157 0.0763 0.85 234 -0.6633 0.8816 0.0567 0.95 198 -0.9558 0.9201 0.0755 0.95 210 0.0834 0.9596 0.0306 0.95 222 -0.4999 0.9058 0.0471 0.95 234 -0.4554 0.9474 0.0446