> 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?

The true KL energy (for true KL).
I'm looping against neutral candidates (MC). If I find a true KL (idMc ==
130) I'm getting the fourmomentum and then plotting the energy.

I'm not applying constraint to the MC particle to be reconstructed in the
EMC: I'll add that constraint and redo the plots (btw: I do not have the
information in the MC block... how can I impose that constraint on true
KL???).

> 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?
>

No constraint on EMC recostruction is applyed.
So I need to plot the ecalGam energy? But how can I do that selecting true
KL if the MC association is broken?
I can:
a) Plot the true energy for true KL
b) Plot reco/ecal energy for KL that have the highest likelihood to be a
kaon

I cannot plot the ecal energy for true KL because I do not know how to
match them.

>
>
>  > (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)

I do not understand this: I'm plotting the TRUE energy for TRUE KL.
Why do I need the likelihood selection? If I ask for true KL what can be
improved by the likelihood selection?

Should I select 'TRUE' KL on a likelihood basis and that's it?
Otherwise I do not understand how to plot reco/ecal quantities for TRUE
KL....

>
> > 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've redone the plot (the previous one had a bug)
http://www.slac.stanford.edu/~asarti/recoil/devel/KLstu/energy_best_KL_sup.eps

All that study is made unusable by the fact that I was using MC
association for KL (it is known that doesn't works but I forgot it..)

> >
> 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!!

I can't. That study is going to be dropped.
I remember someone asking for data-MC comparison for true and fake KL
but I realize now that can't be done on MC index basis (the only thing
that can be done is making data-MC comparisons for those events that have
a likelihood < 0.....: can that be useful?)

> 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,

that plot is using the information on generic that comes from the MC
matching association: if the information is not reliable the plot cannot
be trusted.
I'm going to redo the plot directly on true (not reconstructed) KL were I
do not need to use the associator and see if the statement is still valid.

> then I would
> also suggest Urs runs with the data-MC comparison you showed the other day
> 	ciao
> 	ric
>