CLAS physics database search results Measurement E151M1911 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.45 282 -0.1889 0.6787 0.0321 0.65 114 -0.5197 0.712 0.0435 0.65 126 -1.3653 0.7505 0.088 0.65 198 -0.7534 0.8474 0.0546 0.65 222 0.0094 0.7979 0.03 0.65 282 -0.4717 0.7955 0.0414 0.65 294 1.2599 0.6526 0.082 0.75 66 1.2356 0.7036 0.0807 0.75 198 -0.559 0.8054 0.0452 0.75 222 -0.7707 0.7322 0.0555 0.75 234 -0.1152 0.7185 0.0308 0.75 282 0.0996 0.5833 0.0306 0.75 294 -1.5122 0.636 0.0964 0.85 114 -1.235 0.6999 0.0806 0.85 210 1.4583 0.669 0.0933 0.85 222 0.5651 0.7352 0.0455 0.85 234 -0.0465 0.8506 0.0301 0.85 246 -0.3931 0.7581 0.0383