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Hi all, here is the status of the MC fits. First of all: what is our generation value for BRBR? From the DECAY.DEC of both SP5 and SP6 we see BR(Xclnu) = 10.4% BR(Xulnu) = 0.21% So it seems that BRBR(gen) = 0.21/(10.4+0.21) = 198*10^-4 But if you take the numbers from the MC truth on the ntuples, we get on the Mx fit _without_ signal unfolding: Vub events (truth-matched) passing the SL selection and with mX<1.55: 9705 total SL events (truth-matched): 434239 pstarfactor (truth-matched): 1.05 ===> BRBR (from MC truth): 9705/434239/1.05 = 213*10^-4 The Mx fit without unfolding gives (229+/-7+-6)*10^-4. In this fit the same MC sample (generic BB Run1-4) has been used as both data and MC. This is not the right thing to do, but at least it shows the effect due to mES fits, since they are done on "data" only whereas we are simply counting the truth-matched events for MC. Results from this fit are at http://www.slac.stanford.edu/~bozzi/scra/IbuMCmXfixVubfixResfixSB/ The fit with signal unfolding is still not ready yet, at the moment there is a problem in getting the right phase space acceptance (i.e. the one from DFN as it comes out from DECAY.DEC). We will post a recipe on how to run MC fits as soon as we are convinced that we are doing the right thing on signal-unfolded MX fits. The difficult part is to check that we are not applying any reweighting on the MC, since our data set is MC without reweighting. Ciao, Concezio & Antonio.