CLAS physics database search results Measurement E151M2122 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.45 270 0.5758 0.8056 0.048 0.55 126 -0.5445 0.8444 0.0464 0.75 234 -0.0417 0.8743 0.0301 0.75 246 1.327 0.848 0.0914 0.75 282 -1.2238 0.6654 0.0851 0.75 294 0.445 0.8117 0.0417 0.85 102 0.9807 0.8141 0.0705 0.85 222 -0.021 0.9558 0.03 0.85 234 -0.9346 0.8746 0.0678 0.45 282 0.375 0.7233 0.0457 0.65 114 -0.5864 0.945 0.0617 0.65 138 -0.5206 0.9169 0.0565 0.75 138 0.5538 0.9948 0.0591 0.75 222 -0.7121 0.949 0.072 0.75 234 0.4338 0.8475 0.0499 0.85 90 1.2262 0.9788 0.1166 0.85 102 0.2313 1.1996 0.0368 0.85 222 0.3621 0.9614 0.0448 0.85 234 -0.4745 0.9922 0.0529