CLAS physics database search results Measurement E151M2390 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.75 90 1.2513 0.8887 0.0956 0.85 78 -0.2591 1.0708 0.0354 0.85 90 1.1127 0.9945 0.0861 0.85 102 0.1252 1.0078 0.0313 0.85 186 1.173 0.9431 0.0902 0.85 198 1.6626 1.0024 0.1242 0.85 210 -0.2152 0.9714 0.0338 0.85 222 -1.2429 0.9645 0.095 0.85 234 0.8065 0.8365 0.0657 0.95 186 -0.1455 0.9097 0.0318 0.95 198 -0.0645 1.0197 0.0304 0.95 210 -0.5286 0.9942 0.0487 0.95 234 0.4662 0.7945 0.0452 0.95 246 0.1464 0.7791 0.0318 0.95 258 1.1959 0.9449 0.0918