CLAS physics database search results Measurement E42M1 eg1b H.Avakian 2000 x A_1 Data errors dimensionless dimensionless dimensionless 0.15 0.2352 0.0466 0.21 0.3169 0.026 0.27 0.371 0.0253 0.33 0.468 0.03 0.39 0.5084 0.0384 0.45 0.6268 0.0544