CLAS physics database search results Measurement E151M2134 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.55 126 -0.4633 1.1123 0.0521 0.65 222 0.5 1.1439 0.0549 0.85 102 0.6717 1.1869 0.0686 0.85 126 0.6865 1.4553 0.0699 0.45 270 -0.4596 0.7459 0.0424 0.55 270 -0.4078 0.7746 0.04 0.65 114 -0.8608 0.7493 0.0635 0.65 138 1.0194 0.8189 0.0728 0.65 222 -0.6375 0.8365 0.0512 0.75 126 0.7066 0.8295 0.0549 0.75 210 -1.3566 0.8744 0.0932 0.75 282 0.0715 0.6475 0.0304 0.85 114 -0.7987 0.7971 0.06 0.85 210 -1.1437 0.9767 0.0802 0.85 222 -0.2449 0.9216 0.034