CLAS physics database search results Measurement E151M1232 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.45 282 0.0276 0.5364 0.0302 0.55 270 -0.6129 0.4713 0.0754 0.55 282 0.0747 0.396 0.0312 0.65 258 -0.1071 0.4685 0.0323 0.65 270 -0.8464 0.3615 0.1001 0.65 282 0.3086 0.4958 0.046 0.75 258 -0.3827 0.3939 0.0526 0.75 270 -0.623 0.3683 0.0764 0.85 138 -0.321 0.527 0.047 0.85 150 0.1952 0.5117 0.0372 0.85 162 -0.0433 0.4028 0.0304 0.85 174 -0.0705 0.3663 0.031 0.85 186 0.5626 0.3699 0.0702 0.85 198 -0.0515 0.3508 0.0306 0.85 210 0.3225 0.391 0.0472 0.85 222 -0.0681 0.5435 0.031 0.95 186 -0.0291 0.4117 0.0302 0.95 210 -0.042 0.4266 0.0304