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Just to make also an input to the discussion: To go from 2C to 3C only needs a change in one of the call variables ITF=4 (M1-M2=0) -> ITF=6 (M1=M0(1) ; M2=M0(2)) Please do not forget to set M0(1) and M0(2) to the B pole mass!!!!! As an alternative approach you also could test ITF=7 (alpha1*M1=M0(1) alpha2*M2=M0(2)) where alpha1 and alpha2 are Gaussian parameters with a width of G0(I) I=1,2. G0(I) should be the width of the B mass resolution after reconstruction. In principal thats the right way to go ... but feel free to try both. Oliver By the way, ITF=6 and ITF=7 are both 3C (6-3) fits On Thu, 4 Apr 2002, Luth, Vera G. wrote: > > Hi Riccardo, > > ad 3) > I am told by Oliver that so far we only use a 2-C fit. I do not understand why? > we have 3-C available. It would be good to clarify this. > If there is no difference, why? > Vera > > > > -----Original Message----- > From: Faccini, Riccardo > Sent: Wednesday, April 03, 2002 09:14 AM > To: vub-recoil > Subject: mumblings on MX reconstruction > > > Hello folks, > while writing the paragraph on X and neutrino four-momentum reconstruction > I reviewed the code and the logic and I have a couple of comments: > 1) B0rectrk is a bit map and not an index. The way it is implemented > right now it is hardwire and relies on the assumption of a single > candidate being reconstructed. I think we should do something slightly > safer ... > 2) in the case of identified leptons in the X system , when > reconstructing the X 4-momentum, we assign the electron and muon mass. > Since our analysis assumption is that we have only one lepton in the event > (and this needs to be true in the signal), would it be wiser to assign the > pion mass to these candidate? If there is actually an additional lepton in > the background the reconstructed MX will be pulled up, which is not bad... > 3) do I read the code correctly that we are using the 2C fit with the > equal B mass constraint? Also reading the code it looks like that when you > turn the smearing on you turn off this additional constraint. I have no > clue what this means (I guess it is a testing configuration) but it sounds > wierd > > ciao > ric > P.S. I committed a revised version of chapter 3 according to what I think > we agreed upon. Let me know if you are not happy with it. > >