ALPGEN MC Generation at SPRACE - Grid Production

Introduction

Large scale ALPGEN event production cannot be made in a single step - a preliminary production has to be made, in order to allow ALPGEN to optimize its knowledge of the phase space structure. For a given process, this structure is constant and can be saved in what is called a grid file, to be reused for later productions of the same kind. The production of a grid file consists of a series of warm-up cycles (~5 to 10) of the generator, each cycle generating O(1M) events, followed by the production of O(10M) of events. This page describes some grid productions done at SPRACE and elsewhere, and has links to the relevant files.

Grid Productions

TTbar + jets

  • Sample description: Top-antitop events.
  • Collider: proton-proton.
  • Center of mass energy: 10 TeV.
  • Matching (ICKKW setting): yes (1).
  • Top mass: 175 GeV
  • Top decay mode: fully inclusive.
  • ALPGEN version: 2.13
1          ! generation mode
ttbar4j_40 ! string labeling the output files
0          ! start with: 0=new grid, 1=previous warmup grid, 2=previous generation grid
4000000  5 ! N(events)/iteration and N(iter's) for initial grid optimiz
50000000   ! number evts to generate
*** The above 5 lines provide mandatory inputs for all processes
*** (Comment lines are introduced by the three asteriscs)
*** The lines below modify existing defaults for the hard process under study
*** For a complete list of accessible parameters and their values,
*** input 'print 1' (to display on the screen) or 'print 2' to write to file
njets 4
ebeam 5000
ih2 1
ickkw 1
ptjmin 40
etajmax 5
drjmin 0.7
mt 175
ihvy 6
itdecmode 7

These grids were originally produced for the Summer 2008 Production for the CMS Collaboration. The thresholds for parton production were set at 30, 40 and 50 GeV. The grids were produced for 0, 1, 2, 3 and 4 partons. The matching efficiencies quoted were derived with PYTHIA showering done inside the CMSSW framework (CMSSW version 2_2_3, PYTHIA version 6.416).

Sample Events / cycle Cycles Asked events WGT events WGT Xsec (pb) Error (pb) UNW events UNW Xsec (pb) Error (pb) Unweighting efficiency Matched events Matching Xsec (pb) Error (pb) Matching efficiency
ttbar0j_30GeV 4000000 5 50000000 6462816 2.02E+03 1.06E+01 1136665 1.90E+02 9.47E-02 2.27E-002 702390 1.18E+02 5.85E-02 0.618
ttbar0j_40GeV 4000000 5 50000000 6462816 2.02E+03 1.06E+01 1136665 1.90E+02 9.47E-02 2.27E-002 795122 1.33E+02 6.63E-02 0.700
ttbar0j_50GeV 4000000 5 50000000 6462816 2.02E+03 1.06E+01 1136665 1.90E+02 9.47E-02 2.27E-002 860824 1.44E+02 7.18E-02 0.757
ttbar1j_30GeV 4000000 6 50000000 2120429 1.53E+03 9.33E+00 424774 1.64E+02 1.21E-01 8.50E-003 159965 6.18E+01 4.57E-02 0.377
ttbar1j_40GeV 4000000 6 50000000 2350711 1.17E+03 9.61E+00 453316 1.21E+02 8.66E-02 9.07E-003 194990 5.21E+01 3.73E-02 0.430
ttbar1j_50GeV 4000000 6 50000000 2585228 9.08E+02 9.70E+00 506646 9.37E+01 6.56E-02 1.01E-002 236252 4.37E+01 3.06E-02 0.466
ttbar2j_30GeV 4000000 7 50000000 190817 7.52E+02 7.57E+00 35558 8.73E+01 2.03E-01 7.11E-004 8410 2.06E+01 4.81E-02 0.237
ttbar2j_40GeV 4000000 7 50000000 237619 4.35E+02 7.89E+00 46028 4.94E+01 9.63E-02 9.21E-004 12701 1.36E+01 2.66E-02 0.276
ttbar2j_50GeV 4000000 7 50000000 298591 2.75E+02 8.07E+00 59939 3.07E+01 5.29E-02 1.20E-003 18102 9.27E+00 1.60E-02 0.302
ttbar3j_30GeV 4000000 8 50000000 262729 4.15E+02 8.65E+00 39244 3.49E+01 6.64E-02 7.85E-004 5835 5.19E+00 9.87E-03 0.149
ttbar3j_40GeV 4000000 8 50000000 376197 1.88E+02 9.15E+00 48051 1.54E+01 2.58E-02 9.61E-004 8515 2.74E+00 4.57E-03 0.177
ttbar3j_50GeV 4000000 8 50000000 339983 1.00E+02 9.82E+00 56262 7.87E+00 1.26E-02 1.13E-003 11006 1.54E+00 2.47E-03 0.196
ttbar4j_30GeV 4000000 9 50000000 208188 2.02E+02 1.03E+01 20263 1.15E+01 2.53E-02 4.05E-004 2760 1.56E+00 3.44E-03 0.136
ttbar4j_40GeV 4000000 9 50000000 155193 7.33E+01 1.13E+01 25736 4.04E+00 8.59E-03 5.15E-004 3854 6.05E-01 1.29E-03 0.150
ttbar4j_50GeV 4000000 9 50000000 180885 3.09E+01 1.14E+01 30121 1.71E+00 3.56E-03 6.02E-004 4854 2.75E-01 5.74E-04 0.161

W + jets

Z + jets

-- ThiagoTomei - 13 May 2009

Topic revision: r5 - 2009-06-05 - ThiagoTomei
 

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