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correction in emc bump splitting [message #7669]

Tue, 13 January 2009 04:10

Dima Melnychuk
Messages: 213
Registered: April 2004
Location: National Centre for Nucle...

first-grade participant

From: 94.254.162*

Hi all,

I have corrected the small bug in emc code which affected bump splitting and particularly calculation of the bump position. (rev.4314)

The energy of the bumps was calculated properly but to suppress merged pi0, we need not only energies of the bumps but also opening angle of pi0. And the bug in the calculation of bump position resulted in wrong opening angle and as a result in low efficiency of the merged pi0 suppression.

The pictures below gives some demonstration of the bump splitting for 200 event, 5 GeV pi0 generated in [30;60] degree theta range.

The following picture presents the MC Truth energy of gamma's from pi0 decay and reconstructed energy of EmcClusters.

index.php?t=getfile&id=4903&private=0

The same for EmcBumps
index.php?t=getfile&id=4904&private=0

i.e. the energy distribution is reproduced.

The opening angle of pi0 for MC Truth and EmcClusters
index.php?t=getfile&id=4905&private=0

And reconstructed opening angle for EmcBumps
index.php?t=getfile&id=4906&private=0

And finally pi0 invariant mass for EmcClusters
index.php?t=getfile&id=4907&private=0

and EmcBumps
index.php?t=getfile&id=4908&private=0

i.e. without bump splitting only 10 % of pi0 are reconstructed.

All the pictures are plotted with bump_analysis.C macro.

Best regards,
Dima

Attachment: egamma_cluster.png
(Size: 12.29KB, Downloaded 1183 times)
Attachment: egamma_bump.png
(Size: 12.78KB, Downloaded 1167 times)
Attachment: pi0_angle_cluster.png
(Size: 14.55KB, Downloaded 1169 times)
Attachment: pi0_angle_bump.png
(Size: 14.19KB, Downloaded 1102 times)
Attachment: m_pi0_cluster.png
(Size: 12.41KB, Downloaded 1226 times)
Attachment: m_pi0_bump.png
(Size: 12.14KB, Downloaded 1204 times)

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Re: correction in emc bump splitting [message #7671 is a reply to message #7669]

Tue, 13 January 2009 15:54

Bertram Kopf
Messages: 110
Registered: March 2006

continuous participant

From: *ep1.ruhr-uni-bochum.de

Hi Dima,

great! So my question to you and especially to Irina: Is it now possible to obtain reasonable results for the gamma gamma studies which should go to the Physics Book?

Best regards,
Bertram.

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Re: correction in emc bump splitting [message #7674 is a reply to message #7671]

Tue, 13 January 2009 23:16

Johan Messchendorp
Messages: 693
Registered: April 2007
Location: University of Groningen

first-grade participant

From: *xs4all.nl

Dear all,

I am re-running the analysis part of the simulations for the gamma gamma studies at the KVI.... with the latest revision. This should not take too long, since I am only re-running a part of the simulation.

Johan.

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Re: correction in emc bump splitting [message #7847 is a reply to message #7674]

Fri, 06 February 2009 12:58

Irina Brodski
Messages: 8
Registered: October 2008

occasional visitor

From: *physik.uni-giessen.de

Dear all,

this correction improved the bump splitting for pi0-events, but i still have a problem with gamma gamma events and there is still a factor of 2-5 for the background above 3 GeV to suppress.
Here a little macro to explain.

Please please run it with:
root -l "Fehlersuche.C(\"gammagamma.root\",7.5298 )"
root -l "Fehlersuche.C(\"pi0pi0.root\",7.5298 )"

Many single gamma-clusters in the shashlyk are split in two.
Maybe someone can help me?
Thank you,
Irina

Attachment: pi0pi0.root
(Size: 6.27MB, Downloaded 490 times)
Attachment: gammagamma.root
(Size: 4.19MB, Downloaded 474 times)
Attachment: Fehlersuche.C
(Size: 5.78KB, Downloaded 422 times)

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Re: correction in emc bump splitting [message #7848 is a reply to message #7847]

Fri, 06 February 2009 13:46

Dima Melnychuk
Messages: 213
Registered: April 2004
Location: National Centre for Nucle...

first-grade participant

From: *fuw.edu.pl

Hi Irina,

Small correction to your post. From the data file gammagamma.root it looks like that some single gamma clusters are split into 2 bumps not in shashlyk but in forward endcap (slightly above 2 meters in Z direction) and there is no single event with clusters in shashlyk.

And it looks like that problem is related with what Bertram posted http://forum.gsi.de/index.php?t=rview&goto=7833#msg_7833

I tried to solve it but still without success.

Dima

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Re: correction in emc bump splitting [message #7850 is a reply to message #7848]

Fri, 06 February 2009 15:05

Bertram Kopf
Messages: 110
Registered: March 2006

continuous participant

From: *ep1.ruhr-uni-bochum.de

Hi Irina and Dima,
just one additional remark:

Dima Melnychuk wrote on Fri, 06 February 2009 13:46

Hi Small correction to your post. From the data file gammagamma.root it looks like that some single gamma clusters are split into 2 bumps not in shashlyk but in forward endcap (slightly above 2 meters in Z direction) and there is no single event with clusters in shashlyk.

And it looks like that problem is related with what Bertram posted http://forum.gsi.de/index.php?t=rview&goto=7833#msg_7833

Due to the fact that only events with |cos(Theta*)|<0.6 are considered, the shashlyk detector doesn't contribute at all. The reconstructed gamma hists either the barrel calorimeter or the forward endcap. The backward endcap is also important in order to see low energetic gammas originated from the pi0 background.

Best regards,
Bertram.

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Re: correction in emc bump splitting [message #7879 is a reply to message #7850]

Fri, 13 February 2009 22:33

Irina Brodski
Messages: 8
Registered: October 2008

occasional visitor

From: *dip0.t-ipconnect.de

Yes, Bertram is right. I mean the detektor part on a position of >200. This should be the endcup

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Re: correction in emc bump splitting [message #7929 is a reply to message #7669]

Thu, 19 February 2009 21:48

Johan Messchendorp
Messages: 693
Registered: April 2007
Location: University of Groningen

first-grade participant

From: *xs4all.nl

Hi,

I started a new series of simulations with the older forward endcap design, as we discussed this afternoon. The jobs are in the queue. For Irina, the results will appear at kvip81 (once the jobs start running, though) at the location:

/daq/panda/simgg_feb09/....

Kind wishes,

Johan.

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