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snowmass2013:montecarlo_d2

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Delphes2 samples

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 PYTHIA8 and HERWIG++ models, and processed using the Delphes 2.03 fast detector simulation.

All data are stored as ROOT files using the standard Delphes 2.0.3 output. Therefore, it is recommended to install Delphes 2.0.3 and look at the example explaining how to read such ROOT files (see the directory “Examples” inside the Delphes package).

Information about the geometry (resolutions) is given in these Delphes input files (comes with the default Delphes installation):

There is a bug for b-tagging in Delphes 2.03 and it is recommended to redo jet b-tagging offline for this version. Consider using Delphes 3.0 (beta). See the bottom of this page.
For the pile-up simulation, look at Energy Frontier FastSimulation page. Some information for ATLAS users can be found here.

The output ROOT files have the truth information and the detector-level objects (jets, leptons etc).

How to download MC samples

Please read How to download the link the link

How to analyse MCs

First you need to install ROOT. Then the procedure is somewhat different depending on what Delphes version you are using, “Delphes 2.03” (production) or Delphes 3.0 (beta). Go to the Delphes web page and download the needed version. The packages contain basic examples of how to read ROOT files generated by Delphes. One example for Delphes 3.0(beta) is given in this section

Let's do some analysis using the files given on this web page. Download Delphes_V_2.0.3.tar.gz and compile it (should work on Scientific Linux 5 or 6): 

wget --no-check-certificate https://cp3.irmp.ucl.ac.be/projects/delphes/raw-attachment/wiki/WikiStart/Delphes_V_2.0.3.tar.gz
tar -zvxf Delphes_V_2.0.3.tar.gz
cd Delphes_V_2.0.3/
make

You will see this:

Click to display ⇲

Click to hide ⇱ 

>> Generating tmp/Utilities/ExRootAnalysis/src/BlockClassesDict.cc
>> Compiling tmp/Utilities/ExRootAnalysis/src/BlockClassesDict.cc
>> Generating tmp/src/TreeClassesDict.cc
>> Compiling tmp/src/TreeClassesDict.cc
........................................ many messages
>> Building Frog_on_analysis_output
>> Compiling Examples/Convertors_Only.cpp
>> Building Convertors_Only
Delphes has been compiled
Ready to run

The directory “Examples” contains the example source code. Let's replace it with our example program. snowmass_tutorial.tgz 

mv Delphes_V_2.0.3/Examples Delphes_V_2.0.3/Examples_old
cd /tmp
wget --no-check-certificate https://mc.hep.anl.gov/asc/wikidoc/lib/exe/fetch.php?media=snowmass2013:snowmass_tutorial.tgz
tar -zvxf snowmass_tutorial.tgz
mv /tmp/snowmass_tutorial/* Delphes_V_2.0.3/  # copy the content to the Delphes installation
cd Delphes_V_2.0.3/
make  # recompile again

The new code which is inside “Examples” calculated some basic histograms for the top production. You can run it using the script “A_RUN”. Open it and define the path to the directory with ROOT files. The run it as “./A_RUN”. The program runs over the list of ROOT files and creates a ROOT file with histograms inside “out/” directory.

TTbar production at high pT

The generator-level settings are given below. No pile-up was included.

PYTHIA8 samples

The events were generated with this input card: analysis.ini. The luminosity info and cross section for 5000 generated events can be found here:

Click to display ⇲

Click to hide ⇱ 

 *-------  PYTHIA Event and Cross Section Statistics  -------------------------------------------------------------*
 |                                                                                                                 |
 | Subprocess                                    Code |            Number of events       |      sigma +- delta    |
 |                                                    |       Tried   Selected   Accepted |     (estimated) (mb)   |
 |                                                    |                                   |                        |
 |-----------------------------------------------------------------------------------------------------------------|
 |                                                    |                                   |                        |
 | g g -> t tbar                                  601 |       43612       2785       2785 |   2.039e-10  1.833e-12 |
 | q qbar -> t tbar                               602 |       21140       2215       2215 |   1.616e-10  1.798e-12 |
 |                                                    |                                   |                        |
 | sum                                                |       64752       5000       5000 |   3.655e-10  2.568e-12 |
 |                                                                                                                 |
 *-------  End PYTHIA Event and Cross Section Statistics ----------------------------------------------------------*

 *-------  PYTHIA Error and Warning Messages Statistics  ----------------------------------------------------------*
 |                                                                                                                 |
 |  times   message                                                                                                |
 |                                                                                                                 |
 |     22   Error in Pythia::next: hadronLevel failed; try again                                                   |
 |     22   Error in StringFragmentation::fragment: stuck in joining                                               |
 |      1   Warning in MultipartonInteractions::pTnext: weight above unity                                         |
 |     17   Warning in SpaceShower::pT2nextQCD: weight above unity                                                 |
 |     17   Warning in StringFragmentation::fragmentToJunction: bad convergence junction rest frame                |
 |                                                                                                                 |
 *-------  End PYTHIA Error and Warning Messages Statistics  ------------------------------------------------------*
== Cross section for this run=3.655e-01 pb
== Events for this run=5000
== Luminosity for this run=1.368e+01 fb-1
== Number of top-quark events =813 sigma (fb)=5.942e+01
== Number of W  events =206 sigma (fb)=1.506e+01
== Number of Z  events =0 sigma (fb)=0.000e+00

Get the ROOT files from the download link

Example for downloading 5 files: 

python download.py 5 pythia8/ttbar650pt pythia8_ttbar_pt650

I total there are 80 files to download. This gives 80×5000=400,000 events.

HERWIG++ samples

The log file for 5000 generated events is here:

Click to display ⇲

Click to hide ⇱ 


==============================================================================
Total:                                    155528       155528      2.31111e+08
==============================================================================
Per matrix element breakdown:
MEQCD2to2Fast                             155528       155528      2.31111e+08
==============================================================================

==============================================================================
Eikonalized and soft cross sections:

Model parameters:                    ptmin:   3.5973 GeV, mu2: 0.81 GeV2
                                     DL mode: 2, CMenergy: 14000 GeV
hard inclusive cross section (mb):   230.943
soft inclusive cross section (mb):   27.5083
total cross section (mb):            113.95
inelastic cross section (mb):        78.5474
soft inv radius (GeV2):              0.306276
slope of soft pt spectrum (1/GeV2):  -0.840612
Average hard multiplicity:           5.46146
Average soft multiplicity:           0.36554
==============================================================================

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>> ThePEG - Toolkit for HEP Event Generation - version 1.8.1 <<<<<<<<<<
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

==============================================================================
Statistics for event handler 'LHCHandler':
                                       generated    number of    Cross-section
                                          events     attempts             (nb)
==============================================================================
Total (from   weighted events): including vetoed events           1.246(9)e-03
==============================================================================
Total (from unweighted events):             5000         5028      1.24(2)e-03
==============================================================================
Per matrix element breakdown:
MEHeavyQuark                                5000         5028      1.24(2)e-03
==============================================================================

Get the ROOT files from the download link

Example for downloading 5 files: 

python download.py 5 herwigpp/ttbar650pt herwigpp_ttbar_pt650

In total, there are 80 files to download. This gives 80×5000=400,000 events.

QCD (multijet) background

The total luminosity for inclusive QCD jet sample is roughly 9.6 fb-1 (for each sample, PYTHIA and HERWIG). The files are grouped in 2 directories and one should combine them to get ~9.6 fb-1.

PYTHIA8 samples

The events were generated with this input card: analysis.ini

Click to display ⇲

Click to hide ⇱ 

*-------  PYTHIA Event and Cross Section Statistics  -------------------------------------------------------------*
 |                                                                                                                 |
 | Subprocess                                    Code |            Number of events       |      sigma +- delta    |
 |                                                    |       Tried   Selected   Accepted |     (estimated) (mb)   |
 |                                                    |                                   |                        |
 |-----------------------------------------------------------------------------------------------------------------|
 |                                                    |                                   |                        |
 | g g -> g g                                     111 |        5470        831        831 |   2.753e-08  4.985e-10 |
 | g g -> q qbar (uds)                            112 |         130         24         24 |   7.833e-10  8.864e-11 |
 | q g -> q g                                     113 |       20816       2679       2679 |   9.207e-08  8.796e-10 |
 | q q(bar)' -> q q(bar)'                         114 |        9979       1323       1323 |   4.509e-08  6.070e-10 |
 | q qbar -> g g                                  115 |          97         17         17 |   6.241e-10  7.790e-11 |
 | q qbar -> q' qbar' (uds)                       116 |          70         19         19 |   5.035e-10  6.732e-11 |
 | g g -> c cbar                                  121 |          52          4          4 |   1.507e-10  3.342e-11 |
 | q qbar -> c cbar                               122 |          23          7          7 |   1.925e-10  4.638e-11 |
 | g g -> b bbar                                  123 |          33          6          6 |   2.810e-10  6.515e-11 |
 | q qbar -> b bbar                               124 |          22          8          8 |   2.282e-10  5.441e-11 |
 | q g -> q gamma (udscb)                         201 |          17          2          2 |   1.968e-10  5.069e-11 |
 | q qbar -> g gamma                              202 |           8          4          4 |   6.074e-11  2.082e-11 |
 | g g -> g gamma                                 203 |           0          0          0 |   0.000e+00  0.000e+00 |
 | f fbar -> gamma gamma                          204 |           0          0          0 |   0.000e+00  0.000e+00 |
 | g g -> gamma gamma                             205 |           0          0          0 |   0.000e+00  0.000e+00 |
 | f fbar -> gamma*/Z0                            221 |          59         11         11 |   4.135e-10  7.896e-11 |
 | f fbar' -> W+-                                 222 |         107         31         31 |   8.721e-10  9.339e-11 |
 | f fbar -> gamma*/Z0 gamma*/Z0                  231 |           4          1          1 |   6.196e-12  6.196e-12 |
 | f fbar' -> Z0 W+- (no gamma*!)                 232 |           2          0          0 |   0.000e+00  0.000e+00 |
 | f fbar -> W+ W-                                233 |           4          0          0 |   0.000e+00  0.000e+00 |
 | q qbar -> gamma*/Z0 g                          241 |          19          2          2 |   6.789e-11  3.454e-11 |
 | q g-> gamma*/Z0 q                              242 |         101         11         11 |   2.479e-10  5.253e-11 |
 | f fbar -> gamma*/Z0 gamma                      243 |           0          0          0 |   0.000e+00  0.000e+00 |
 | q qbar' -> W+- g                               251 |          35          3          3 |   1.787e-10  3.979e-11 |
 | q g-> W+- q'                                   252 |         118         17         17 |   5.763e-10  6.943e-11 |
 | f fbar' -> W+- gamma                           253 |           2          0          0 |   0.000e+00  0.000e+00 |
 |                                                    |                                   |                        |
 | sum                                                |       37168       5000       5000 |   1.701e-07  1.203e-09 |
 |                                                                                                                 |
 *-------  End PYTHIA Event and Cross Section Statistics ----------------------------------------------------------*

== Cross section for this run=1.701e+02 pb
== Events for this run=5000
== Luminosity for this run=2.940e-02 fb-1
== Number of top-quark events =0 sigma (fb)=0.000e+00
== Number of W  events =2 sigma (fb)=6.803e+01
== Number of Z  events =3 sigma (fb)=1.020e+02

Get the ROOT files grouped in 2 directories:

Example for downloading 5 files: 

python download.py 5 pythia8/qcd650pt/run1 pythia8_qcd_pt650
python download.py 5 pythia8/qcd650pt/run2 pythia8_qcd_pt650_2

HERWIG++ samples

The MC samples were generated for inclusive jets events. The part of the log file with the cross sections is shown below (for 5000 events):

Click to display ⇲

Click to hide ⇱ 

Miscellaneous output from modules to the standard output:

Statistics for the UE process:
                                       generated    number of    Cross-section
                                          events     attempts             (nb)
==============================================================================
Total:                                    153340       153340      2.30923e+08
==============================================================================
Per matrix element breakdown:
MEQCD2to2Fast                             153340       153340      2.30923e+08
==============================================================================

==============================================================================
Eikonalized and soft cross sections:

Model parameters:                    ptmin:   3.5973 GeV, mu2: 0.81 GeV2
                                     DL mode: 2, CMenergy: 14000 GeV
hard inclusive cross section (mb):   231.373
soft inclusive cross section (mb):   27.2365
total cross section (mb):            113.95
inelastic cross section (mb):        78.5401
soft inv radius (GeV2):              0.304806
slope of soft pt spectrum (1/GeV2):  -0.884655
Average hard multiplicity:           5.47163
Average soft multiplicity:           0.360742
==============================================================================

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>> ThePEG - Toolkit for HEP Event Generation - version 1.8.1 <<<<<<<<<<
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

==============================================================================
Statistics for event handler 'LHCHandler':
                                       generated    number of    Cross-section
                                          events     attempts             (nb)
==============================================================================
Total (from   weighted events): including vetoed events           0.168(1)e+00
==============================================================================
Total (from unweighted events):             5000         5038     0.167(3)e+00
==============================================================================
Per matrix element breakdown:
MEQCD2to2                                   4989         5027     0.166(3)e+00
MEGammaJet                                     4            4      0.13(7)e-03
MEZJet                                         1            1       30(30)e-06
MEWJet                                         6            6      0.20(8)e-03
==============================================================================

Get the ROOT files from these 2 locations:

Example for downloading 5 files: 

python download.py 5 herwigpp/qcd650pt/run1 herwigpp_qcd_pt650
python download.py 5 herwigpp/qcd650pt/run2 herwigpp_qcd_pt650_2

— Sergei Chekanov 2013/01/31 08:52

snowmass2013/montecarlo_d2.txt · Last modified: 2014/04/24 01:51 (external edit)

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