CLAS physics database search results Measurement E19M8 E89-004 R. A. Schumacher 2005 cos(theta) Cz Data errors dimensionless dimensionless dimensionless -0.7 1.482 0.619 -0.4 0.262 0.267 -0.1 1.075 0.162 0.2 0.528 0.142 0.5 0.706 0.148 0.8 0.351 0.205