CLAS physics database search results Measurement E151M1912 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.55 222 -1.0036 0.7895 0.0678 0.65 126 0.2264 0.8048 0.033 0.65 138 -0.5803 0.8528 0.0462 0.65 222 0.6295 0.7578 0.0485 0.65 294 1.4102 0.6101 0.0906 0.75 66 0.3013 0.8328 0.0351 0.75 138 -0.0402 0.8623 0.0301 0.75 198 0.5983 0.8144 0.0471 0.75 210 0.2182 0.8556 0.0328 0.75 222 0.7568 0.7523 0.0548 0.75 234 -0.4231 0.6619 0.0395 0.75 282 -0.7252 0.7247 0.0532 0.85 102 0.5121 0.7904 0.0432 0.85 234 -1.3208 0.6137 0.0855 0.95 234 -1.5116 0.5396 0.0964