Fit Type B:  Fit the mass peak for the signal region definition
Obtain the error on the signal region definition from that fit:
Mean: 3.09354
Sigma:0.0159857
Norm: 31801.6
Signal fraction: 0.901879+/-0.000930529
The fitted value of tau:     0.0447288+/-0.000863798
The fitted value of Lambda+: 0.0611172+/-0.00270954
The fitted value of Lambda-: 0.0592963+/-0.00252171
The fitted value of F+:      0.145042+/-0.00505567
The fitted value of F-:      0.0802706+/-0.00345505
The fitted value of Scale:   1.07052+/-0.00536526
The fitted value of alpha:   0.900831+/-0.000921104
The fitted value of Bfrac:   0.183755+/-0.00281955