CLAS physics database search results Measurement E151M2162 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.55 282 -0.1773 0.6425 0.0326 0.65 270 0.7317 0.6533 0.0609 0.65 282 -0.8331 0.5039 0.0674 0.65 294 1.2424 0.6528 0.095 0.75 270 -0.6154 0.5967 0.0538 0.75 282 -0.2841 0.5393 0.0364 0.85 66 -0.3868 0.7542 0.0411 0.85 78 0.0842 0.545 0.0306 0.85 90 0.6762 0.584 0.0575 0.85 102 -0.5446 0.5711 0.0496 0.85 114 -0.463 0.7075 0.045 0.85 270 -0.7759 0.6375 0.0638 0.85 282 -1.4487 0.7329 0.1092 0.95 54 1.0012 0.6654 0.0786 0.95 78 -0.0216 0.5807 0.03 0.95 90 -1.1529 0.4993 0.0888 0.95 102 0.6009 0.5379 0.0529 0.95 114 0.0685 0.6468 0.0304 0.95 126 -0.8522 0.5336 0.0687 0.95 138 -0.4102 0.8262 0.0422