Hi everyone,
I am getting some strange results from my ntuples.
I am working in:
~penguin/vubrecoil/vub30/workdir
I have two generic chains of ntuples:
chains/B0B0bar1235.C
chains/BpBm1237.C
But when I plot the reconstructed
Breco charge ("brecocharge") for each chain,
I get lots of +/-1 in the B0B0bar sample,
and lots of 0 in the BpBm sample. See:
~penguin/vubrecoil/vub30/workdir/SP1235.gif
~peneguin/vubrecoil/vub30/workdir/SP1237.gif
So I was kind of worried, because I would have thought
BSemiExcl would do better than that.
I wanted to find an MC truth variable so I could
check the true charge of the B mesons, but I ran into
trouble there, too.
First I thought I'd try "IdBtrue". This comes from the code:
fIdBtrue = (int)pTruthRecoil->getRecoCandidate()->pdtEntry()->lundId();
in VubXlnu.cc. I had assumed this would be the usual PDT
numbers: ie, +/-511 for B0 and B0bar, and +/-521 for Bp and Bm.
But when I looked at IdBtrue in my ntuples, all the entries were 1.
Then I tried "ch1B". I thought it might be the charge of a B meson.
In the code it is:
fch1B = (int)(pTruthRecoil->getmatchesReco()).first;
I tried to trace it back in the code but it got very confusing.
It looks like it's actually the value of a counter.
Anyway, the plots showed lots of values greater than 1, so
I guess this is not the B meson charge.
So I guess I have 3 questions:
(1) Why does the BSemiExcl skim assign the wrong charge to
so many of the B mesons? Is this normal?
(2) What is IdBtrue?
(3) How can I confirm that the true B meson charges are
what they are supposed to be? Is there any variable that
will give me the true B charge?
Thanks,
sheila
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