Home » PANDA » PandaRoot » General » Psi analysis as a cross check from donghee kang
Psi analysis as a cross check from donghee kang [message #12501] |
Wed, 17 August 2011 12:37 |
donghee
Messages: 385 Registered: January 2009 Location: Germnay
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first-grade participant |
From: *dip.t-dialin.net
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Hi Panders,,,,
I would like to show you and to make sure, the psi(3770) benchmark channel is in principle being cross checked.
Here is a brief summary (presentation), which you can get some numbers global acceptance and resolutions of D+, D-, psi, and its products.
General way of psi analysis is based on the MC true PID matching (assuming ideal PID) and it found that TPC and STT show similar performance.
Vertex resolution for D+ and D- are found to be level of 100 micro meter for z and 60 micro meter for x and y position.
Mass resolutions are roughly 10-20 MeV for D mesons with both STT and TPC mode.
Please have a look this note, and welcome any comments and suggestions for further analysis.
Marius is main analyzer of psi(3770) channel, it might be useful to get a confirmation of this analysis from him, whether all results are reasonable or not.
Thank you...
Donghee
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Re: Psi analysis as a cross check from donghee kang [message #12510 is a reply to message #12509] |
Wed, 17 August 2011 17:59 |
donghee
Messages: 385 Registered: January 2009 Location: Germnay
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first-grade participant |
From: *dip.t-dialin.net
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Hi Lars,
So now I'm clear(?), the reconstruced tracks, specially in STT mode,
I have to check whether tracks are passing through the STT physical volume or not, explicitly.
Then it means that technically I can require at least one hit on STT, which must be revealed in the defined tracklet of psi product, otherwise STT didn't join to tracking stage.
If it so, that is easy to handle it. Those events will be easily rejected.
But if you meaned soem test volume itself, I have to think about it. How can be done...
If there some other clever or efficient way to do that, please let me know.
Cheers,
Donghee
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Re: Psi analysis as a cross check from donghee kang [message #12522 is a reply to message #12515] |
Thu, 18 August 2011 13:09 |
Gianluigi Boca
Messages: 177 Registered: March 2004
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first-grade participant |
From: *gsi.de
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Hi Donghee, Lars and others.
I have a request to Donghee and a comment to Lars and all the other TPC guys.
Donghee, do you have time to plot the effective masses for the Stt in the cases when you have 2, 3, 4, ......, 10 hits minimum?
I am curious to see if the mass resolution changes with the number of hits.
Comment to Lars and the TPC guys.
If I understand how the TPC works, it is necessary to have a certain track length in the TPC for the reconstruction, otherwise it doesn't work (am I right Felix ?)
The STT can work also with less points (actually in PR at least 2).
Instead of banging all the time on the number of hits in the Stt, why don't we have the results of TPC+Mvd to compare with Stt+Mvd ? That makes more sense instead of trying to reduce 'artificially' the STT efficiency with hits requests and complaining that we quote the STT+Mvd pattern recognition.
On the other hand, if the TPC people think they are better off not using the Mvd system, then it is their choice and they must live with their track length requirement.
Nevertheless some day we need to see how the TPC+MVD system works. We need also to see how well the matching TPC/Mvd works in realistic conditions and with which efficiency.
Last remark : I am modifying the code to turn off (if the user wants) the part of the STT+MVD Pattern Recognition that starts from Mvd hits and goes to STT.
This part of the code was criticized lately, so soon users can not use it if they want.
Gianluigi
Lars Schmitt wrote on Thu, 18 August 2011 11:24 | Dear Donghee,
Your results are very instructive. This means that the efficiencies of TPC
and STT in reconstructing tracks are actually similar, since the TPC asks
for a minimal track length. If this would correspond to something like
7 hits in the STT the resulting efficiencies would be the same.
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Re: Psi analysis as a cross check from donghee kang [message #12523 is a reply to message #12522] |
Thu, 18 August 2011 13:29 |
Felix Boehmer
Messages: 149 Registered: May 2007 Location: Munich
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first-grade participant |
From: *natpool.mwn.de
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Hello Gianluigi,
I think you mis-interpret the motivation behind this effort. The goal is simply to make a direct comparison with what we have, not "artificially" reduce the performance of the STT system. Now to your comments:
Quote: | f I understand how the TPC works, it is necessary to have a certain track length in the TPC for the reconstruction, otherwise it doesn't work (am I right Felix ?)
The STT can work also with less points (actually in PR at least 2).
Instead of banging all the time on the number of hits in the Stt, why don't we have the results of TPC+Mvd to compare with Stt+Mvd ? That makes more sense instead of trying to reduce 'artificially' the STT efficiency with hits requests and complaining that we quote the STT+Mvd pattern recognition.
On the other hand, if the TPC people think they are better off not using the Mvd system, then it is their choice and they must live with their track length requirement.
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If we had the time to implement another PR approach that directly involves found hits/tracks in the MVD or GEMs, the TPC would also "work" with a single hit (even though the use of this single hit is quite debatable) - there is no conceptual advantage that I see that would make this approach any more effective for the STT system. I agree, then we could directly compare the two complete tracking detector setups, however under the assumption that the CT will never play a role in the trigger decision.
However, we chose a different approach that emphasizes the TPC as a stand-alone tracking system that is also capable of contributing to the trigger decision, since there are cases where there is information that is only available in the CT (V0's in the CT acceptance for instance).
I have never seen this effort from the STT side. The hard reliance on information from other detectors on the pattern recognition level is NOT an advantage! Also, reducing the central tracker to a mere supportive role for track property extraction should not be the basis of a pure comparison of the central tracker options in my opinion.
It will be necessary to have a clear list of requirements for the CT especially in terms of trigger decision and DAQ philosophy at some point before we can take the decision.
Best Regards,
Felix
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Re: Psi analysis as a cross check from donghee kang [message #12524 is a reply to message #12522] |
Thu, 18 August 2011 14:00 |
donghee
Messages: 385 Registered: January 2009 Location: Germnay
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first-grade participant |
From: *kph.uni-mainz.de
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Dear Gianluigi,
Of course, I have time to do that, I will try it.
Best regards,
Donghee
Quote: |
Donghee, do you have time to plot the effective masses for the Stt in the cases when you have 2, 3, 4, ......, 10 hits minimum?
I am curious to see if the mass resolution changes with the number of hits.
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Re: Psi analysis as a cross check from donghee kang [message #12525 is a reply to message #12523] |
Thu, 18 August 2011 14:42 |
Gianluigi Boca
Messages: 177 Registered: March 2004
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first-grade participant |
From: *gsi.de
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Felix Boehmer wrote on Thu, 18 August 2011 13:29 | Hello Gianluigi,
I think you mis-interpret the motivation behind this effort. The goal is simply to make a direct comparison with what we have, not "artificially" reduce the performance of the STT system. Now to your comments:
Quote: | f I understand how the TPC works, it is necessary to have a certain track length in the TPC for the reconstruction, otherwise it doesn't work (am I right Felix ?)
The STT can work also with less points (actually in PR at least 2).
Instead of banging all the time on the number of hits in the Stt, why don't we have the results of TPC+Mvd to compare with Stt+Mvd ? That makes more sense instead of trying to reduce 'artificially' the STT efficiency with hits requests and complaining that we quote the STT+Mvd pattern recognition.
On the other hand, if the TPC people think they are better off not using the Mvd system, then it is their choice and they must live with their track length requirement.
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If we had the time to implement another PR approach that directly involves found hits/tracks in the MVD or GEMs, the TPC would also "work" with a single hit (even though the use of this single hit is quite debatable) - there is no conceptual advantage that I see that would make this approach any more effective for the STT system. I agree, then we could directly compare the two complete tracking detector setups, however under the assumption that the CT will never play a role in the trigger decision.
However, we chose a different approach that emphasizes the TPC as a stand-alone tracking system that is also capable of contributing to the trigger decision, since there are cases where there is information that is only available in the CT (V0's in the CT acceptance for instance).
I have never seen this effort from the STT side. The hard reliance on information from other detectors on the pattern recognition level is NOT an advantage! Also, reducing the central tracker to a mere supportive role for track property extraction should not be the basis of a pure comparison of the central tracker options in my opinion.
It will be necessary to have a clear list of requirements for the CT especially in terms of trigger decision and DAQ philosophy at some point before we can take the decision.
Best Regards,
Felix
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Hi Felix, I don't understand.
Don't forget that the STT role in the Pattern Recognition is essential, since we start from STT to decide the tracks that are good or not.
The fraction of tracks found from Mvd going to SST has always been negligible and mainly ghost tracks.
Also for the trigger point of view I don't understand your remark at all. If you are referring to the fact that the V0 code for STT is not final yet, that I agree. You should aknowledge on the same way that there hasn't been extensive presentations on the V0 code of the TPC.
Gianluigi
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Re: Psi analysis as a cross check from donghee kang [message #12546 is a reply to message #12535] |
Mon, 22 August 2011 15:44 |
StefanoSpataro
Messages: 2736 Registered: June 2005 Location: Torino
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first-grade participant |
From: *17-79-r.retail.telecomitalia.it
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Hi,
I don't well understand the strange theta distributions for TPC, in slide 18. It seems they are not so continuous such as in the STT case (22) but thereis a sort of step. Do you have an idea on what is happening there?
Moreover, your D invariant mass plots for STT have a sort of tail which is not present in the case of Marius analysis. Which are the main differences between the two analyses?
[Updated on: Mon, 22 August 2011 15:53] Report message to a moderator
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Re: Psi analysis as a cross check from donghee kang [message #12566 is a reply to message #12547] |
Wed, 24 August 2011 22:43 |
donghee
Messages: 385 Registered: January 2009 Location: Germnay
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first-grade participant |
From: *dip.t-dialin.net
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Dear panda,
I have corrected and updated few slides in this note.
Some binnings are readjusted and pion resolutions are completed with full statistics.
please find the new version of material for psi analysis.
Good nights.
Donghee
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