CLAS physics database search results Measurement E19M5 E89-004 R. A. Schumacher 2005 cos(theta) Cx Data errors dimensionless dimensionless dimensionless -0.7 -0.729 0.67 -0.4 -0.007 0.257 -0.1 -0.437 0.157 0.2 -0.131 0.137 0.5 -0.552 0.139 0.8 -0.074 0.205