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Photon energy distribution using DPM [message #13269] Wed, 28 March 2012 18:50 Go to next message
Ganesh Tambave is currently offline  Ganesh Tambave
Messages: 5
Registered: June 2009
Location: groningen
occasional visitor
From: *KVI.nl
Dear All,

I have tried to reproduce fig.3.2 (please find attached: EMCTDR_fig.3.2.png) shown in EMC TDR page no.33 using DPM event generator to estimate pile-up probabilites.
I have reproduced it for 15 GeV anti-proton (please find attached: dpm_photon_2D.png and it's y-projection for theta 5 to 21 deg.: dpm_photon_2D_y-proj.png).
If I compare both the figures then they don't look same, the photon energy distribution mean in my figure is about 1.5 GeV and in TDR fig. is about 200 MeV.
Can anyone help me to understand this difference?

I'm using only MC true information from DPM (no detector at all).

Regards,
Ganesh Tambave
Re: Photon energy distribution using DPM [message #13271 is a reply to message #13269] Thu, 29 March 2012 15:41 Go to previous messageGo to next message
StefanoSpataro is currently offline  StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino
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From: 140.181.9*
Is it possible that the DPM plot includes also secondaries? Just trying to guess...
Re: Photon energy distribution using DPM [message #13272 is a reply to message #13271] Fri, 30 March 2012 10:52 Go to previous messageGo to next message
Ganesh Tambave is currently offline  Ganesh Tambave
Messages: 5
Registered: June 2009
Location: groningen
occasional visitor
From: *KVI.nl
Dear Stefano,

Please find attached pdg ID from DPM. I have selected only
photons out of it and plotted photon energy distribution.


Regards,
Ganesh
  • Attachment: dpm_pid.png
    (Size: 6.74KB, Downloaded 271 times)
Re: Photon energy distribution using DPM [message #13273 is a reply to message #13272] Fri, 30 March 2012 10:56 Go to previous messageGo to next message
Johan Messchendorp is currently offline  Johan Messchendorp
Messages: 693
Registered: April 2007
Location: University of Groningen
first-grade participant

From: 202.122.36*
Hi,

The question is what was done for the EMC TDR: did they take the interactions with the detectors into account (DPM+detectors), and hence, showed the distribution of photons including secondaries photons from interactions with the material? Or was the TDR result also without any detectors, e.g. just from the MC of the event generator?


Greets,

Johan.
Re: Photon energy distribution using DPM [message #13274 is a reply to message #13273] Fri, 30 March 2012 11:13 Go to previous messageGo to next message
Ganesh Tambave is currently offline  Ganesh Tambave
Messages: 5
Registered: June 2009
Location: groningen
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From: *KVI.nl
Dear Johan,

I'm sorry, I don't know the details of TDR fig. since I don't know who made it.

But I have produced photon energy distribution using DPM+forward endcap EMC using EMC hit information. About the forward endcap geometry, I used all panda EMC for the simulation and in the analysis I have selected only module==3, which is for Farward endcap emc.

Please find attached,
photon energy vs. angle (emc_hit_dpm_photon_TE.png) and
photon energy distribution (emc_hit_dpm_photon_energy.png)

Regards,
Ganesh
Re: Photon energy distribution using DPM [message #13275 is a reply to message #13274] Fri, 30 March 2012 11:16 Go to previous messageGo to next message
Johan Messchendorp is currently offline  Johan Messchendorp
Messages: 693
Registered: April 2007
Location: University of Groningen
first-grade participant

From: 202.122.36*
Hi,

The producer of the TDR plot is - most likely - Bertram Kopf. You might want to contact him directly about the details of the plot. I furthermore have contacted Aida (she is in charge of the DPM stuff) and asked her to reproduce the spectrum to confirm your observation.

Greets,

Johan.
Re: Photon energy distribution using DPM [message #13279 is a reply to message #13269] Fri, 30 March 2012 18:03 Go to previous messageGo to next message
Aida Galoyan is currently offline  Aida Galoyan
Messages: 79
Registered: May 2007
Location: Dubna
continuous participant
From: *cern.ch
Hi Ganesh,

Looking at your figure 2 at 15 GeV we see that <E_gamma>=1.2 GeV.
In your Fig.3 <E_gamma> = 1.9 GeV. It is due to restriction on the
theta (5 - 21 deg.) According to the TDR fig., it must be so.
Why are you talking about <E_gamma>= 200 MeV?

>>>>>>>>>>>>>
If I compare both the figures then they don't look same, the photon energy distribution mean in my figure is about 1.5 GeV and in TDR fig. is about 200 MeV.
>>>>>>>>>>>>>

In TDR fig., there is no average value of <E_gamma>. I can not see
any question.

Best regards,
Aida
Re: Photon energy distribution using DPM [message #13280 is a reply to message #13279] Fri, 30 March 2012 18:49 Go to previous messageGo to next message
StefanoSpataro is currently offline  StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino
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From: 140.181.11*
From the Tdr picture (figure 1) it is clear that the photon energy distribution is well below 1Gev, different from the new plots. And in those 2D plots there are no polar angle selections.
Re: Photon energy distribution using DPM [message #13284 is a reply to message #13279] Mon, 02 April 2012 13:04 Go to previous messageGo to next message
Ganesh Tambave is currently offline  Ganesh Tambave
Messages: 5
Registered: June 2009
Location: groningen
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From: *KVI.nl
Dear Aida,

Thank you for your reply.

The question is,

If I compare fig.1 (i.e EMC TDR 2D plot) and fig.3 (my figure with theta selection: 5-21 deg), you can see that the vertical axis of fig.1 (EMC TDR 2D plot) photon energy distribution mean is well below 1 GeV (~200 MeV) and in fig.3 (my figure with theta selection: 5-21 deg) it is above 1 GeV (~1.6 GeV).

I was trying to understand the reason behind this difference.

In my studies I have used only DPM generator information and I don't know about the details about EMC TDR fig.

Regards,
Ganesh
Re: Photon energy distribution using DPM [message #13285 is a reply to message #13269] Mon, 02 April 2012 16:51 Go to previous messageGo to next message
Bertram Kopf is currently offline  Bertram Kopf
Messages: 110
Registered: March 2006
continuous participant
From: *ep1.ruhr-uni-bochum.de
Dear Ganesh and all others,
meanwhile, we could reproduce the plots shown in EMC TDR on page 33. We considered the pure MC-truth information of the DPM generator without any secondaries (i.e. w/o the material budget in front of the EMC). In order to get reasonable results we required that all short and long living resonances (pi0, eta, Delta, Sigma, etc.) are decaying within the generator. The new plots for 15GeV/c beam momentum are in good agreement with the figures of the EMC TDR and can be seen here:

a) Egam vs. theta
gam_e_theta.png

b) Egam for 5deg > theta > 21deg
gam_e_in_fwd.png

In addition you can find here the particle list for the first events where at least 1 photon is in the region between 5deg > theta > 21deg:
FirstEvents5To21deg.txt

Of course, our results are in disagreement with the results obtained by Ganesh. At the moment I don't know why. But is it possible that in Ganesh studies all long living particles like Lambda, Sigma, etc. are required to be stable?

Best regards,
Bertram.
Re: Photon energy distribution using DPM [message #13289 is a reply to message #13269] Tue, 03 April 2012 15:01 Go to previous messageGo to next message
Bernhard Roth is currently offline  Bernhard Roth
Messages: 8
Registered: February 2009
Location: Bochum
occasional visitor
From: *ep1.ruhr-uni-bochum.de
Hello everybody,

I've repeated the study from yesterday (Bertram has posted about that before), but now with the current DPM generator taken from PandaRoot. Therefore I have ported it to the BaBar-like software, just to be able to compare the results.

The distribution I got is the same as in the EMC TDR, as shown in the attached file. (DPM generated events at 15GeV beam momentum)

And bye the way: by turning off the elastic scattering (Elastic=0.) in pgenerators/DpmEvtGen/main.cc, the generator is about 100 times faster.

Regards,
Bernhard
Re: Photon energy distribution using DPM [message #13300 is a reply to message #13289] Thu, 05 April 2012 09:23 Go to previous messageGo to next message
Johan Messchendorp is currently offline  Johan Messchendorp
Messages: 693
Registered: April 2007
Location: University of Groningen
first-grade participant

From: *xs4all.nl
Hi,

I understand from Ganesh that the problem is now solved.... it was indeed the secondaries. For instance the pi0s were not decaying by default by the generator (done by the transport model). Ganesh was basically looking only at the "hard photon" spectrum from DPM....

Greets and thanks to all for the comments,

Johan.
Re: Photon energy distribution using DPM [message #13301 is a reply to message #13300] Thu, 05 April 2012 10:07 Go to previous message
Ganesh Tambave is currently offline  Ganesh Tambave
Messages: 5
Registered: June 2009
Location: groningen
occasional visitor
From: *KVI.nl
Dear all,

Thank you very much.

Regards,
Ganesh
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