CLAS physics database search results Measurement E19M4 E89-004 R. A. Schumacher 2005 cos(theta) Cz Data errors dimensionless dimensionless dimensionless -0.7 0 0 -0.4 0.734 0.325 -0.1 1.092 0.208 0.2 1.019 0.189 0.5 0.744 0.184 0.8 0.585 0.279