CLAS physics database search results Measurement E151M1971 EG4 Xiaochao Zheng 2016 cos(theta_pi+) phi(pi+) A_LL Stat. error Syst. error degrees 0.65 270 0.3094 0.5478 0.0361 0.75 90 -0.2847 0.4989 0.0353 0.75 270 0.4491 0.5487 0.0419 0.75 282 1.1829 0.5183 0.0826 0.75 294 -0.1716 0.5262 0.032 0.85 66 -0.1289 0.5879 0.0311 0.85 90 -0.4123 0.5355 0.0402 0.85 282 0.7139 0.5743 0.0553 0.95 282 1.7892 0.8234 0.1202 0.55 282 -1.9508 1.7042 0.1818 0.65 270 -0.5665 1.844 0.0601 0.65 282 -1.636 1.7435 0.1533 0.75 270 3.217 1.7499 0.2972 0.75 282 0.4 1.9668 0.0474 0.85 66 2.7304 2.4432 0.2527 0.85 90 2.6566 2.5582 0.246 0.85 102 -0.7438 2.5915 0.0746 0.85 294 -3.6809 2.0118 0.3396 0.95 78 -0.0321 6.8066 0.0301