Hi Daniele,

On Thu, 11 Dec 2003, Daniele del Re wrote:

>
> Hi,
>
>  if your second option means that you will get the background fractions by
> fitting mX distribution with the default binning (one bin for mX<1.55GeV)
> and then use them by subtract the bkg to the mX distribution with your
> favorite binning, I would agree with that.
Exactly.

>  You can have two different "optimized" binning, one for the BR extraction
> and one for the unfolding. I would avoid to have differrent b->ulnu
> subtracted normalizations.
That's what I thought.

>  Take also into accout that we are also studying the possibility to fit
> by using the q2 vs mX plane. Then your second option will be the only one.
OK.

Thanks for your feedback. If nobody is objecting
we will go in this direction then.

Cheers,
Heiko

>  Daniele
>
>
> > Hi,
> >
> > there is a principal question for the unfolding which I would
> > like to raise and ask for feedback.
> >
> > Since we have to choose some binning (which in general will
> > differ from the binning chosen for the fit) there are two
> > ways to go:
> >
> > 1) We choose 'our' equidistant binning, perform a fit where
> >    all bins up to the cut value (1.55 GeV) are combined in
> >    one bin and choose the result of this fit to produce the
> >    final MX histo to be unfolded.
> >
> >    In this case we would not get exactly the same answer for
> >    the branching ratio determination due to the different
> >    binning above the cut value although the effect should be
> >    small if the bin sizes do not get too small.
> >
> > 2) We perform the fit with the original binning and use the
> >    outcome of this fit to produce the final MX-histo with
> >    the bining chosen for the unfolding.
> >    That is, we force that the result of the original fit is
> >    taken into account to subtract the b->c and other BG.
> >
> >    I guess the second alternative is the more natural one.
> >
> > Please let us know what do you prefer.
> >
> > Cheers,
> > Heiko and Kerstin
> >
>