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Hi Oliver [incidentally I realized that your mails never get to vub-recoil because you send files in attachment and they get rejected. In order to circulate a plot to vub-recoil you need to send a web address] > > > lets settle this cfit case and concentrate on the > "DATA vs MC" and "MCcock vs MCgen" comparison. > > > > I am not sure that I understand your statement that the cocktail mc > > > has a better resolution than the generic MC. Attached to this mail > > > you will find a comparison of the Mx resolution obtained from cocktail > > > and generic for sp4run2 MC. After a 1bin (!) sideband subtraction they > > > seem to be pretty much identical. Are I am missing something? > > > By the way, the plot are made with 0.5 GeV missing mass cut and > > > P*>1.0 GeV. It should match the cuts used for the Vub stuff. > > > > I am sorry but I disagree on the fact that the two plots are identical: > > the generic is clearly biassed on the high side wrt to the cocktail and > > maybe also the resolution is slightly different > > ciao > > ric > > > > > > The discrepancy between ~-1.0 and ~-0.25 GeV you are > referring to is just an artifact of my sideband > isubtraction. As pointed out in my previous mail > I only use one bin in Mx in order to carry out > this subtraction. > The negative region of Mx(true) - Mx(reco) > corresponds to "high Mx(reco)" values where > we expect to have the largest contribution from > the sideband background. Therefore, the sideband > subtraction in our analysis is always performed in > bins of Mx in order to account for this correlation. > I have attached a plot showing the same Mx(true)-Mx(reco) > distribution but this time the sideband subtraction > is only performed between -1.5 and 0 GeV. This already > reduces the discrepancy between "MCcock vs MCgen" > a lot demonstrating that it is just an artifact > rather that a real effect. In our Mx moment > analysis we are using 5 Mx bins for the high mass > region in order to make this sideband subtraction. > If you want I can send you the plots - they clearly show > that the cocktail MC and the generic MC are leading > to very similar (identical within errors) > resolutions and shapes for MX. > > I guess "MCcock vs MCgen" is also something > we can settle now and move forward to our biggest > problem the "DATA vs MC" discrepancy (don't you agree?!) The plots you and daniele show go in the direction that here is an effect, but I agree that there are bigger ones. I am trying to get the required smearing to apply to the Breco in coctail in order to reproduce the generic. If this were enough to remove the discrepancies I this we would have taken one degree of confusion out of the discussion ciao ric