CLAS physics database search results Measurement E19M25 E89-004 R. A. Schumacher 2005 cos(theta) Cx Data errors dimensionless dimensionless dimensionless -0.7 -1.507 0.71 -0.4 0.253 0.872 -0.1 0.956 1.071 0.2 0.137 0.581 0.5 -0.53 0.337 0.8 -0.015 0.327