CLAS physics database search results Measurement E19M12 E89-004 R. A. Schumacher 2005 cos(theta) Cz Data errors dimensionless dimensionless dimensionless -0.7 -0.965 0.592 -0.4 0.693 0.328 -0.1 0.854 0.194 0.2 0.419 0.149 0.5 0.149 0.141 0.8 0.097 0.228