CLAS physics database search results Measurement E151M328 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Data errors Systematic errors degrees 0.55 222 0.0578 0.592 0.0386 0.65 222 -0.316 0.6629 0.0358 0.65 234 -0.7128 0.5493 0.0534 0.75 234 -1.3176 0.5718 0.0869 0.55 246 -0.5701 0.6853 0.0456 0.65 210 -0.2978 0.8453 0.035 0.65 222 -0.1717 0.9463 0.0317 0.85 222 -0.2492 0.9033 0.0335 0.85 234 -0.8613 0.5241 0.0599