CLAS physics database search results Measurement E151M2407 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.65 270 -0.9484 0.9565 0.075 0.75 90 0.7543 1.0236 0.0624 0.75 102 0.4809 1.1058 0.046 0.75 114 -1.5168 0.8637 0.114 0.75 186 0.2855 0.9791 0.0365 0.75 198 -1.1983 0.8922 0.0919 0.75 210 -0.515 0.8795 0.0479 0.75 258 0.0557 0.9671 0.0303 0.75 270 -2.2044 0.8319 0.1626 0.75 282 -0.5384 1.0383 0.0492 0.85 102 -1.4386 0.8138 0.1085 0.85 114 -0.2788 0.8717 0.0362 0.85 126 -1.8523 0.8515 0.1376 0.85 174 -0.6819 0.9759 0.0578 0.85 186 -0.286 0.8472 0.0365 0.85 198 0.2808 0.7756 0.0363 0.85 210 0.5597 0.7381 0.0505 0.85 222 -1.5305 0.8677 0.115 0.85 270 0.4035 0.9929 0.0419