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Cluster energy overestimated [message #9135] Tue, 04 August 2009 13:00 Go to next message
donghee is currently offline  donghee
Messages: 385
Registered: January 2009
Location: Germnay
first-grade participant
From: *dip.t-dialin.net
Dear EMC experts,

I have seen that estimated energy with finding cluster in EMC is slightly overestimated.
You find related 3 plots in attached files.

MC true and reconstructed energy are compared in theta and momentum bin.
You can clearly see the overestimated energy in energy resolution 2D plot.

EMC_g_mom_the_distribution.eps (red=MC, blue=reconstructed)
EMC_g_energy_resolution_2D.eps
EMC_g_theta_resolution_2D.eps

If I have a look for electron case, same amount of energy is also shifted.
I'm wondering how the calibration have been done. and how do we can correct wrongly reconstructed energy in EMC.


Best regards,
Donghee
Re: Cluster energy overestimated [message #9141 is a reply to message #9135] Wed, 05 August 2009 14:07 Go to previous messageGo to next message
mpeliz is currently offline  mpeliz
Messages: 51
Registered: February 2008
Location: Ruhr-Universitaet Bochum
continuous participant
From: *ep1.ruhr-uni-bochum.de
Hi Donghee,

the applied calibration method is described in the EMC TDR.
We calibrate on the mean value of the asymmetric distribution of the reconstructed energy, not on it's maximum value. Therefore the "shift" you observed in your resolution plot.
The broad spread for a few events in your plot could come from split offs or photons going to the edge barrel/endcap or forward/Shashlyk.

However, the parameters of the calibration were taken from the Babar-like software which uses a different Geant version then the actual one used by PandaROOT. Therefore -at least- some fine tuning is necessary and we are looking for volunteers.

Sincerely,
Marc


Re: Cluster energy overestimated [message #9142 is a reply to message #9141] Wed, 05 August 2009 15:08 Go to previous message
donghee is currently offline  donghee
Messages: 385
Registered: January 2009
Location: Germnay
first-grade participant
From: *kph.uni-mainz.de
Dear Marc Pelizaeus,

Thank you for your kind explanation.

Best wishes,
Donghee
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