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Vub measurement using recoil of fully reconstructed Bs

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From:
Riccardo Faccini <[log in to unmask]>
Date:
13 Mar 2003 03:18:11 -0800 (PST)Thu, 13 Mar 2003 03:18:11 -0800 (PST)
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Ciao Alessio,

On Wed, 12 Mar 2003, Alessio Sarti wrote:

> Hi all,
> Ive performed the new checks on KL that were discussed in the last
> meeting.
> 1) I've added in anaRecoil two histograms filled by default.
> They contain the information on the energy of TRUE KL.
> Here's the result for  generic B0 2000:
> (as it comes... next time I'll promise to use log scale)
> http://www.slac.stanford.edu/~asarti/recoil/devel/KLstu/energyKL.eps
what are you plotting here?
You should have run over all photon candidates, requested to be
reconstructed in the EMC (this is what we are studying) and plot the ecal
energy. How can there be seros in your plot?



 > (with a cut on energy = 0)
> http://www.slac.stanford.edu/~asarti/recoil/devel/KLstu/energyKLnz.eps
>
Do you understand the bump at 2.5 GeV? It is completely irrealistic, how
can a D meson with 3 GeV of energy release 2.5 of them in a Kl so often?!?

Once you redo the plots, can you also do the plot for likelihhod>0 (only
true kls, though)

> 2) Study of true and fake Klongs:
> Here are the results..
>
> This is (just for 2002 generic MC SP4 B0) energy of all Klongs selected
> with the makimum likelihood method with, superimposed, the same spectrum
> JUST for true Klongs. Discrepancies are not large (are expected?).
> http://www.slac.stanford.edu/~asarti/recoil/devel/KLstu/all_vs_true-KL.eps
>
I am surprised that the true KL are so many, you are telling us, that
almost all  likelihood>0 candidates in MC are true KL!. if this were true
we should just call this events depleted!!!! Are you sure about this?!?
are the two histograms normalized to same lumi?

> The data-MC comparisons are coming separately for true and fake Klongs....
> I needed to rerun the generic in order to have the index of Klongs
> available and jobs are still running: tomorrow I'll post the plots. I do
> not know if Urs want to start the reprocessing with the smearing in the
> meanwhile.....

I don;t understand how can you make a data-MC comaprison for true KL!! We
do not need that, but what escapes me is how could you do the  previous
plots if you do not have the mc truth for KL in generic, this is what you
should have used, I thought.

> > 3) Urs(all)I'm proposing to add in anaQa the following: >
>     //Correction applied to True Klongs.
>     if( idGam[i] == 130 ){
>       energyGam[i] *= (0.274351/0.225545);
>     }
>
> in the loop that makes the four momentum of neutral particles.
> That should be added before ANY use of energyGam[i] variable.
> Let me know if you want me to commit that piece of code in recoilNtp.cc in
> such a way that Urs has a clear example of what I'm proposing before
> translating it to anaQa.

I think the first plots (the mc truth ones) need to be remade, I cannot
believe them, but if you are really positive about the plot that says that
basically all candidates we select with like>0 are true Kl, then I would
also suggest Urs runs with the data-MC comparison you showed the other day
	ciao
	ric



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