CLAS physics database search results Measurement E151M1663 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.55 210 0.1168 1.3548 0.0308 0.55 222 -0.7789 0.6617 0.0765 0.65 222 -0.6683 1.1883 0.0491 0.75 222 -0.7031 1.2312 0.0507 0.75 234 -0.7333 0.9879 0.0521 0.85 222 -1.5522 0.6742 0.0951 0.55 234 -0.1199 1.0394 0.0308 0.75 30 -0.9202 0.8844 0.0628 0.75 222 0.4034 0.9013 0.0385 0.75 234 -0.975 0.9737 0.0657 0.85 222 -0.5681 0.843 0.0454 0.85 234 1.1382 0.935 0.0745