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High-pT ttbar with pileup
Here are the links to the existing Monte Carlo samples for top-quark studies generated for the 14 TeV center-of-mass energy (pp collisions). Events were generated with the HERWIG++ model, and processed using the Delphes 3.05 fast detector simulation.
All data are stored in the ROOT format using the standard Delphes 3.05 output. Therefore, it is recommended to install Delphes 3.0.5 and look at the example explaining how to read such ROOT files (see the directory “Examples” inside the Delphes package).
The samples use the ATLAS detector geometry located in “examples/delphes_card_ATLAS.tcl” of the Delphes 3.05 installation. There is only one difference: Jets are reconstructed using AntiKT jets with the cone 0.5.
How to download
Please read the Section How to download
Signal ttbar
This is a ttbar fully inclusive sample without with pT>650 GeV cut on hard subprocesses and without pileup. As before, sqrt(s)=14 TeV, The included processes are:
g g -> t tbar q qbar -> t tbar
Here is the log file for 200 events (one ROOT file).
If you need complete log files for a single ROOT file, take it from
- LHC_signal.log.gz HERWIG++ log file
- Analysis.log.gz Delphes3 log file
Get the Delphes3 ROOT files from this download link In total, there are 96 files, with 200 ttbar events in each. Thus the total number of events is 19200 signal events. The total luminosity is 14,769 pb-1.
Here is an example for downloading 5 files:
python download.py 5 delphes3/ttbar_pt650/signal herwigpp_ttbar_sig_pt650
(set 5 to 96 to download all)
Signal plus pileup
The truth information from the signal MC shown above was used to overlay with 140 pile up events (fixed number, not “Poisson” case!) The events were overplayed at the HEPMC true level (thanks to Andy Buckley for his help and http://pilemc.hepforge.org/ tool), and then were processed using Delphes3.05 (thanks to Dephes3 team which helped to solve technical issues).
Here is the log file for 30000 UE events (which were used as a pool of events for 200 signal events)).
If you need a complete HERWIG++ log file for a single ROOT file, take it from LHC_pileup.log.gz
Get the ROOT files grouped from this download link In total, there are 96 files, with 200 ttbar events in each file. Thus the total number of events is 19200 signal events.
There is a direct correspondence between signal and signa+pileup files. For example:
herwigpp_ttbar_sig_pt650_[N].root (signal) corresponds herwigpp_ttbar_sig_pt650_140mu_[N].root (signal+140 pileups)
where [N] is a number in the range 1- 96.
Here is an example for downloading 5 files:
python download.py 5 delphes3/ttbar_pt650/mu140/signal_pileup herwigpp_ttbar_sig_pt650_140mu
(set 5 to 96 to download all)
Info about true particle record
To reduce ROOT file size, truth information in these ROOT files was slimmed. Please read here.
How to analyze
If you need to find the effect of pileup on top reconstruction or a jet measurement, you need to run the analysis code over signal MC and then over the signal+pileup MC files. Read analyse_d3
— Sergei Chekanov 2013/03/06 20:48
