CLAS physics database search results Measurement E19M9 E89-004 R. A. Schumacher 2005 cos(theta) Cx Data errors dimensionless dimensionless dimensionless -0.7 -0.115 0.767 -0.4 -0.49 0.283 -0.1 -0.312 0.173 0.2 -0.64 0.147 0.5 -0.362 0.143 0.8 -0.047 0.216