CLAS physics database search results Measurement E19M22 E89-004 R. A. Schumacher 2005 cos(theta) Cz Data errors dimensionless dimensionless dimensionless -0.7 0.828 0.649 -0.4 1.377 0.6 -0.1 0.783 0.44 0.2 0.294 0.31 0.5 -0.526 0.229 0.8 -0.17 0.245