CLAS physics database search results Measurement E19M1 E89-004 R. A. Schumacher 2005 cos(theta) Cx Data errors dimensionless dimensionless dimensionless -0.7 0 0 -0.4 -1.348 0.595 -0.1 -0.227 0.379 0.2 -0.792 0.371 0.5 -0.438 0.305 0.8 -0.286 0.442