CLAS physics database search results Measurement E151M901 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.65 126 -0.1857 0.7615 0.0324 0.75 210 0.4683 0.8883 0.0429 0.75 234 1.4356 0.84 0.0989 0.85 90 0.6713 0.7482 0.0533 0.85 102 0.4442 0.8509 0.0418 0.85 222 -0.3241 0.7175 0.0368 0.85 234 1.5773 0.8985 0.1078 0.65 234 -0.8169 0.6382 0.0811 0.65 294 -0.4731 0.6097 0.053 0.75 126 -1.2679 0.7278 0.1208 0.75 294 0.1572 0.6781 0.0333 0.85 102 1.0104 1.029 0.098 0.85 222 -0.2959 0.661 0.0406