CLAS physics database search results Measurement E151M2255 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.55 78 0.451 0.8527 0.0444 0.55 90 2.5448 2.5448 0.187 0.65 78 0.667 0.869 0.0569 0.65 90 -0.7488 0.9387 0.062 0.65 102 -0.3379 0.9828 0.0387 0.65 258 0.7975 0.8626 0.0651 0.75 78 1.2581 0.7844 0.096 0.75 90 1.0742 0.9588 0.0835 0.75 102 1.7053 0.8272 0.1272 0.75 114 -0.6316 0.9828 0.0548 0.75 234 -0.4328 0.8183 0.0434 0.75 258 0.1997 0.7651 0.0333 0.75 270 1.0989 0.7331 0.0851 0.75 282 -0.7055 0.9174 0.0593 0.85 90 1.5756 0.8476 0.1181 0.85 258 2.617 2.617 0.1921 0.85 270 0.9822 0.8342 0.0773 0.85 282 2.1734 0.6547 0.1604 0.85 294 0.986 0.6604 0.0775 0.85 306 -0.1638 0.7249 0.0323 0.95 258 -0.1352 0.7834 0.0316 0.95 306 -0.2124 0.7785 0.0337