CLAS physics database search results Measurement E151M484 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Data errors Systematic errors degrees 0.55 270 -0.2551 0.5189 0.0338 0.55 282 0.029 0.4384 0.0301 0.55 294 0.5656 0.5212 0.0458 0.65 270 1.6648 1.6648 0.1061 0.65 282 0.6806 0.5948 0.0513 0.75 90 -0.6881 0.4909 0.0517 0.75 270 0.0836 0.5564 0.0304 0.75 282 -0.2476 0.4362 0.0336 0.85 78 -0.4963 0.4689 0.0427 0.85 90 -0.4143 0.4314 0.0393 0.85 102 -0.3215 0.4684 0.0359 0.85 270 0.3843 0.5625 0.0381 0.85 294 -0.8155 0.411 0.0582 0.95 114 1.0037 0.5543 0.0683