CLAS physics database search results Measurement E151M403 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_UL Stat. error Syst. error degrees 0.55 138 -1.3139 0.6492 0.0846 0.65 222 3.6668 3.6668 0.2228 0.75 222 2.2088 1.1215 0.1364 0.75 234 0.3547 0.9725 0.0368 0.55 222 0.393 0.6717 0.0386 0.65 138 -1.0678 0.6718 0.0726 0.65 222 1.0081 0.6542 0.0693 0.75 222 0.5406 0.6091 0.045 0.85 126 0.321 0.6939 0.036 0.85 222 1.3002 0.5916 0.0859