Hi all, I repeated the fit using Mx instead of the fitted Mx. These are the results: Q=0 All BRBR = 0.0175419 +- 0.00407794(stat) +- 0.00118571(MC stat) chi2=0.883673 B0 BRBR = 0.00401112 +- 0.00680338(stat) +- 0.0019864(MC stat) chi2=0.994055 Bch BRBR = 0.0264318 +- 0.00509347(stat) +- 0.00171483(MC stat) chi2=1.66344 Q=1 All BRBR = 0.0254868 +- 0.00452458(stat) +- 0.00137868(MC stat) chi2=0.891207 B0 BRBR = 0.0142957 +- 0.00719002(stat) +- 0.00221697(MC stat) chi2=1.20538 Bch BRBR = 0.0332868 +- 0.00586739(stat) +- 0.00192195(MC stat) chi2=0.607417 The results are perfectly in agreement with the ones obtained with mxhadfit (compare with the table in the BAD). The errors are of the same order. You can comment the chi square by yourself. Daniele