CLAS physics database search results Measurement E19M30 E89-004 R. A. Schumacher 2005 cos(theta) Cz Data errors dimensionless dimensionless dimensionless -0.7 0.072 1.251 -0.4 2.485 0.89 -0.1 -2.157 1.191 0.2 -0.382 0.883 0.5 -0.207 0.476 0.8 0.181 0.797