CLAS physics database search results Measurement E19M11 E89-004 R. A. Schumacher 2005 cos(theta) Cx Data errors dimensionless dimensionless dimensionless -0.7 0.936 0.683 -0.4 -0.406 0.341 -0.1 -0.878 0.195 0.2 -0.731 0.153 0.5 -0.55 0.139 0.8 0.168 0.201