CLAS physics database search results Measurement E19M16 E89-004 R. A. Schumacher 2005 cos(theta) Cz Data errors dimensionless dimensionless dimensionless -0.7 1.157 0.493 -0.4 1.089 0.417 -0.1 0.397 0.249 0.2 0.111 0.213 0.5 0.159 0.155 0.8 -0.193 0.164