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Re: Update on eta_c reconstruction with STT and TPC [message #12399 is a reply to message #12398] Fri, 29 July 2011 19:06 Go to previous messageGo to next message
Johannes Rauch is currently offline  Johannes Rauch
Messages: 41
Registered: September 2010
Location: TUM
continuous participant
From: *natpool.mwn.de
Dear Stefano,

I changed the tpcDetector, and now we can access also secondary tracks from the MCTrackArray.
This is checked in.

But when trying eta_c with mc pid, I get very low efficiencies.

So there is still a bug, but I think its in the reco, not in the sim.


regards,

Johannes
Re: Update on eta_c reconstruction with STT and TPC [message #12400 is a reply to message #12112] Sat, 30 July 2011 09:05 Go to previous messageGo to next message
Dima Melnychuk is currently offline  Dima Melnychuk
Messages: 213
Registered: April 2004
Location: National Centre for Nucle...
first-grade participant
From: *play-internet.pl
Hi Lia,

So running STT reconstruction for eta_c with commented SttMvdGemTracking->SetPdgFromMC();
on the same data set I have the same efficiency around 15% as with this option on. So at least if this is a real drop in efficiency with STT and not a statistical fluctuation it's not the problematic place.

Dima
Re: Update on eta_c reconstruction with STT and TPC [message #12401 is a reply to message #12400] Sat, 30 July 2011 11:06 Go to previous messageGo to next message
Lia Lavezzi
Messages: 291
Registered: May 2007
Location: Torino
first-grade participant

From: *21-151.libero.it
Hi Dima,
thank you for the feedback and good to know that we can exclude this change from the suspects Wink

I was looking again at the IM distributions: the shapes of the distributions of the eta_c IM seem similar. The mean values are 2.852 and 2.848 and the RMS are 0.2142 and 0.2151. Moreover the peak # of entries is 80 in the low statistic case and 8000 in the high statistic one and the counts drop to 40 in the first case and 4000 in the second one. So it could really be only the low statistic.

For the phi IM it is more difficult to say, since the ranges of the histograms are different.

What about the errors on the efficiency calculation? Do you think that the two efficiencies (low and high stat) are compatible within the errors?

The grid sample has been simulated in the july11 release, right?

I would ask also Gianluigi to comment on this, since maybe he knows of possible causes of the drop in efficiency that I miss.

Cheers,
Lia.

Re: Update on eta_c reconstruction with STT and TPC [message #12402 is a reply to message #12112] Sat, 30 July 2011 12:09 Go to previous messageGo to next message
Dima Melnychuk is currently offline  Dima Melnychuk
Messages: 213
Registered: April 2004
Location: National Centre for Nucle...
first-grade participant
From: *play-internet.pl
Hi Lia,

Looking on the number of counts in eta_c peak with 80 vs 8000, I can add that number of analysed events is 2000 vs 100k. So drop of efficiency by factor 2 appears already on this level.

And concerning the error at lower statistics (calculating it as a square root of number of reconstructed eta_c) it' about 1%, i.e. 15+/-1 % vs 23%. So the numbers are not really compatible within errors, (may be it's just a matter of fluctuation).

> The grid sample has been simulated in the july11 release, right?

Yes.

By monday I will try to calculate a litle bit higher statistics, i.e. 5000 events. And here I have a question to Gianluigi if I should update the code to his commit from yesterday night?

Dima
Re: Update on eta_c reconstruction with STT and TPC [message #12403 is a reply to message #12402] Sat, 30 July 2011 12:23 Go to previous messageGo to next message
Felix Boehmer is currently offline  Felix Boehmer
Messages: 149
Registered: May 2007
Location: Munich
first-grade participant

From: *dip.t-dialin.net
Hi Dima,

Just a quick question:
do you observe any differences in the efficiency with larger samples between pion and kaon hypotheses in the fit?


Cheers

Felix
Re: Update on eta_c reconstruction with STT and TPC [message #12404 is a reply to message #12402] Sat, 30 July 2011 15:34 Go to previous messageGo to next message
Lia Lavezzi
Messages: 291
Registered: May 2007
Location: Torino
first-grade participant

From: *21-151.libero.it
Quote:

Looking on the number of counts in eta_c peak with 80 vs 8000, I can add that number of analysed events is 2000 vs 100k. So drop of efficiency by factor 2 appears already on this level.

And concerning the error at lower statistics (calculating it as a square root of number of reconstructed eta_c) it' about 1%, i.e. 15+/-1 % vs 23%. So the numbers are not really compatible within errors, (may be it's just a matter of fluctuation).

Hi Dima,
you are right, considering these numbers I am also wondering if it is really just statistics. Let' s see what happens with more events.
Cheers,
Lia.

Re: Update on eta_c reconstruction with STT and TPC [message #12405 is a reply to message #12112] Sat, 30 July 2011 17:57 Go to previous messageGo to next message
Dima Melnychuk is currently offline  Dima Melnychuk
Messages: 213
Registered: April 2004
Location: National Centre for Nucle...
first-grade participant
From: *play-internet.pl
Hi Felix,

the numbers I quoted in one of my post, i.e.

Efficiency | sigma(eta_c) | sigma(phi)
pion:
27.04% | 11.74 MeV | 3.61 MeV
kaon:
27.29% | 11.94 MeV | 3.55 MeV

is for 2000 events statistics, and producing higher number of events is rather time consuming. And here statistical errors for efficiency are around 1.3%. I plan till Monday to produce 5000 events with pion hypotheis, but it will not decrease errors below the difference between pion and kaon hypotheses I quote here.

Dima
Re: Update on eta_c reconstruction with STT and TPC [message #12406 is a reply to message #12405] Sat, 30 July 2011 18:27 Go to previous messageGo to next message
StefanoSpataro is currently offline  StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino
first-grade participant

From: *6-87-r.retail.telecomitalia.it
Just one comment,
The ideal id shows a nice residual for low momentum, while the wrong hypothesis gives bad tails which we cannot show to referees. For etac we can cheat using the default kaon hypothesis, but in psi channel the problem will appear again. The working ideal id would be the better solution, I think
Re: Update on eta_c reconstruction with STT and TPC [message #12407 is a reply to message #12406] Sat, 30 July 2011 18:30 Go to previous message
Felix Boehmer is currently offline  Felix Boehmer
Messages: 149
Registered: May 2007
Location: Munich
first-grade participant

From: *adsl.alicedsl.de
Hi Stefano,

I completely agree. Johannes is working on finding the problem there... we'll give an update on Monday!


Cheers

Felix
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