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| Re: eta_c reconstruction efficiency [message #12704 is a reply to message #12702] |
Fri, 07 October 2011 11:19   |
Lia Lavezzi
Messages: 291
Registered: May 2007
Location: Torino
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first-grade participant |
From: *pv.infn.it
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Hi Dima,
I performed some test with the etac channel, both in july11 and aug11 releases.
I can confirm that the problem of the efficiency loss arises already after the reconstruction, so after the PR + Kalman step.
I attach here two files with the reco - MC momentum distributions for the primary tracks coming from etac: etacjul11.pdf and etacaug11.pdf. You can see that in aug11 there is the efficiency drop.
Unfortunately this was not visible with box generated muons @ 1 GeV/c (see boxgenjul11.pdf and boxgenaug11.pdf attached here).
So indeed the problem seems in the tracking part (I have to take back what I said at the last tracking EVO  )
Ciao,
Lia.
P.S.: forgot to mention: the purple number on the histos is the integral of the histo between the two dotted lines.
[Updated on: Fri, 07 October 2011 11:21] Report message to a moderator |
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| Re: eta_c reconstruction efficiency [message #12732 is a reply to message #12724] |
Wed, 19 October 2011 18:07 |
StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino
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first-grade participant |
From: *to.infn.it
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Dear all,
I have started also to investigate the problem of the eta_c efficiency loss.
For this I have run the simulation chain up to SttMvdTracking, w/o genfit, using the trnk PndSttMvdracking.* and comparing with the july11 version.
The followings are the invariant mass distributions for eta_c and phi, with trunk and july11:
 
You can see there are no differences.
After, I run the same but also genfit:
 
Here the difference is evident, even if the kalman code is exactly the same for the two options.
I suspected it was connected with the montecarlo id hypothesis of the mctrackassociator, and I have run genfit using the standard muon hyp:
 
The same. The problem does not depend on the mc id part.
My guess:
the STTMVD pattern recognition part is fine, it provides nice peaks w/o the kalman. The kalman does some mess with the latest code. Considering that the kalman starts from the track parameters at the first point (which should be fine according to the first plots) and from the trackcand, I suspect that in the latter SttMvdTracking there is some mess with the TrackCand object.
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