CLAS physics database search results Measurement E151M2111 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.65 114 -0.7319 0.9291 0.0737 0.65 126 0.7906 0.8229 0.0786 0.75 126 -1.4046 0.9539 0.1325 0.75 138 -0.5738 1.0035 0.0607 0.75 282 0.6293 0.8115 0.0652 0.75 294 -0.6696 0.7011 0.0685 0.85 90 -0.6577 0.9868 0.0675 0.85 102 -0.6669 1.1011 0.0682 0.85 234 0.0787 0.8876 0.0309 0.65 222 -0.5046 0.9441 0.0445 0.75 210 -0.5867 1.0428 0.0485 0.75 222 -0.3313 1.0042 0.0369 0.85 90 -0.0001 0.9214 0.03 0.85 210 -0.8368 1.0952 0.0622 0.85 234 0.292 1.0353 0.0355 0.85 246 -0.2421 0.9834 0.0339