CLAS physics database search results Measurement E19M23 E89-004 R. A. Schumacher 2005 cos(theta) Cx Data errors dimensionless dimensionless dimensionless -0.7 -0.074 0.676 -0.4 0.01 0.686 -0.1 0.97 0.55 0.2 -0.435 0.398 0.5 -0.232 0.24 0.8 -0.042 0.227