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.
>
>
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