CLAS physics database search results Measurement E151M1454 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.55 270 1.0495 0.642 0.0697 0.75 294 0.5263 0.7326 0.0435 0.85 90 1.5522 0.6607 0.0977 0.85 126 -1.0663 0.7076 0.0706 0.45 282 1.004 0.8578 0.0656 0.55 270 0.7681 0.8158 0.0538 0.65 258 1.9475 1.9475 0.1172 0.65 270 -0.0132 0.8562 0.03 0.65 282 -0.9312 0.6008 0.0619 0.85 102 -0.2633 0.9119 0.0337 0.85 114 -0.9017 0.8982 0.0604