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Hi, due to further implementations/testings, we are afraid we cannot provide a tag for VVF by today. However, we got some interesting results by running some Mx fits with the following configurations: (1) fix the S/peakingBG ratio after applying all cuts: in data by using the double ratio technique, in MC by fitting separately truth-matched for S and non-truth-matched events for peakingBG, see http://www.slac.stanford.edu/~bozzi/scra/Ibutest_fixed_usecb/ (2) fix the S/peakingBG ratio in data after applying all cuts as in (1), take all MC quantities (Mx shapes, efficiencies) by simply counting events surviving the cuts in truth-matched events, see http://www.slac.stanford.edu/~bozzi/scra/Ibutest_fixed_count/ If our mES fits are OK, the results obtained in (2) should be compatible with the results obtained in (1). For what the MC shapes are concerned, you will find comparisons in http://www.slac.stanford.edu/~bozzi/comp_vcboth.eps (vcb+other) http://www.slac.stanford.edu/~bozzi/comp_vubin.eps (vubIN) http://www.slac.stanford.edu/~bozzi/comp_vubout.eps (VubOUT) where the points refer to (1), the histograms to (2) and the four plots are: (top left) chargedB, (top right) neutralB opposite flavor, (bottom left) neutralB same flavor, (bottom right) sum of the previous ones, corrected for mixing and charged/neutralB ratio observed in data. The Mx distributions obtained with the two approaches are quite compatible, and indeed the Mx fit on data gives (1) Vub IN fitted 1' bin = 415.428 +- 1.58277(stat MC) +- 30.8589(err fit) Vub OUT fitted 1' bin = 41.1093 +- 2.86677(stat MC) +- 3.02161(err fit) Vcb+Oth fitted 1' bin = 380.874 +- 10.1103(stat MC) +- 11.2604(err fit) (2) Vub IN fitted 1' bin = 415.912 +- 8.34177(stat MC) +- 30.8209(err fit) Vub OUT fitted 1' bin = 38.0393 +- 2.4665(stat MC) +- 2.85527(err fit) Vcb+Oth fitted 1' bin = 383.46 +- 8.57534(stat MC) +- 11.0408(err fit) The efficiencies however are a bit different: (1) Eps_u = 0.440843 +- 0.00529543 Eps_u (mix corr)= 0.445315 +- 0.0053009 Eps_Cut = 0.729764 +- 0.00713367 Eps_PhSp = 0.491828 +- 0.000818 Eps_tot = 0.158227 +- 0.00246454 (2) Eps_u = 0.408981 +- 0.00537718 Eps_u (mix corr)= 0.40782 +- 0.00537481 Eps_Cut = 0.88187 +- 0.00551991 Eps_PhSp = 0.491828 +- 0.000818 Eps_tot = 0.177387 +- 0.00259984 The last number which enters in the BRBR determination is the pstarfactor: (1) pstarfact 1.20276 +- 0.0290694 (2) pstarfact 1.10181 +- 0.0155489 This counterbalances the different efficiencies, giving quite similar results for BRBR: (1) PartialBRBR = 0.0133692 +- 0.000993091(stat) +- 0.000418926(MC stat) BRBR = 0.0271826 +- 0.00201918(stat) +- 0.000852973(MC stat) (2) PartialBRBR = 0.0131184 +- 0.00097213(stat) +- 0.000360179(MC stat) BRBR = 0.0266727 +- 0.00197657(stat) +- 0.00073367(MC stat) Conclusion: the bias on mES fits on MC obtained after determining the S/peakingBG ratio in matched/unmatched events after all cuts is small. There is however some bias on the mES fits on bigger samples, namely the ones used to compute the efficiencies and the pstarfactor, where we don't use matched/unmatched events (e.g. when we require lepton cuts). Therefore we propose to count matched events to compute all MC-related quantities. BTW, this avoids many mES fits and speeds up VVF quite a lot! (3) The above figures can also be compared with the results of VVF without applying any S/peakingBG constraint, as in our first attempts, see http://www.slac.stanford.edu/~bozzi/scra/Ibutest_nofixed/ Comparisons of Mx MC shapes for (2) and (3) are in http://www.slac.stanford.edu/~bozzi/comp_vcboth_nofix.eps http://www.slac.stanford.edu/~bozzi/comp_vubin_nofix.eps http://www.slac.stanford.edu/~bozzi/comp_vubout_nofix.eps points are (3), histograms are (2). Difference are bigger in this case. The Mx fit, efficiencies, pstarfactor, BRBR for (3): (3) Vub IN fitted 1' bin = 494.356 +- 8.76092(stat MC) +- 64.6291(err fit) Vub OUT fitted 1' bin = 44.0603 +- 4.46821(stat MC) +- 5.65902(err fit) Vcb+Oth fitted 1' bin = 334.964 +- 16.6672(stat MC) +- 22.8977(err fit) Eps_u = 0.440843 +- 0.00529543 Eps_u (mix corr)= 0.445315 +- 0.0053009 Eps_Cut = 0.834418 +- 0.00597102 Eps_PhSp = 0.491828 +- 0.000818 Eps_tot = 0.180918 +- 0.00254743 pstarfact 1.20276 +- 0.0290694 PartialBRBR = 0.0139138 +- 0.00181901(stat) +- 0.000577261(MC stat) BRBR = 0.02829 +- 0.00369847(stat) +- 0.00117465(MC stat) Note that the statistical error on the fitted Vub events, and therefore on PartialBRBR and BRBR are about a factor 2 worse than in (1) and (2). This is expected since we are performing mES fits where we determine simultaneously S, peakingBG and combinatorialBG without any further constraints. More news (and new VVF tag!) by tomorrow, Ciao, Antonio & Concezio.