CMS Alpgen sample generation (mostly 2006)

The samples which are listed on this page were supposed to be finished for P-TDR II studies. They have been simulated only partially in ORCA but will be simulated in the new EDM as soon as the production team is ready to take requests.

However, these ntuple files can be used directly as input for fast simulation studies.

Preamble

• An adapted version of CRAB has been provided to perform the generation on the LCG. The version which has been used for the datasets summarized on this page was CRAB_for_Alpgen_8 and was written by Daniele Spiga and Filippo Ambroglini.

• The hard process was generated with ALPGEN v205 CMS .

• The default kinematic cuts in Alpgen are
  • Pt (j,c,b) > 20 GeV
  • |eta (j,c,b)| < 5.0
  • |eta (e,mu,tau)| < 3.0
  • dR(jj) >= 0.7
  • dR(lj) >= 0.0
  • M_top = 175 GeV

• CMS Alpgen default parameter set: AlpPar.txt

• Due to a bug in Alpgen v2.05, the Q-scale choices iqopt=1 and iqopt=3 were swapped for the processes WQQ, ZQQ, Wjet and Zjet.

• CMKIN 6.0.1 was used to process the ME/PS matching within PYTHIA.

• The directory /castor/cern.ch/cms/generation/alpgen205-crab/ contains the crab output as tar balls.

• You can find the corresponding ntuples in /castor/cern.ch/cms/generation/alpgen205-prod06/.

• The generated events are spilt in ntuples of usually 500 events each. But there are also ntuple files with less events (especially for higher jet multiplicities).

Samples

tt + jets (top is allowed to decay inclusively)

[Spiropulu, Chierici, Schmidt]

W + jets (W --> e,mu,tau)

[Segoni, Kasselmann]

Z + jets (Z --> ee/mumu/tautau, 40 GeV < m_ll < 200 GeV)

*These files are named falsely. Don't get confused!

Configuration parameters can be found in /castor/cern.ch/cms/generation/alpgen205-crab/zjets/crab-input/

[Felzmann]

Z + jets Run II

Just some more ntuples generated with exactly the same parameters as the previous run to get more statistics for bins with high jet multiplicity.

[Felzmann]

WW + jets (both Ws decay leptonically into e/mu/tau)

[Karapostoli]

WZ + jets (W --> inclusive, Z --> ee/mumu/tautau)

[Karapostoli]

ZZ + jets (Z --> inclusive, Z --> ee/mumu/tautau)

These ntuples have been generated using the bug fix for ALPGEN version 2.05 provided by MLM correcting the wrong branching ratios in ZZ decays.

ZZbug.txt: Z decay modes in ALPGEN2.05 ZZ+jets

[Felzmann]

Notes

• Cross section is given in pb after matching.

• To calculate the corresponding luminosity in fb-1, divide the number of events by the cross section and multiply the result by 0.001.

• "Exclusive" means exactly n hard jets (according to the ALPGEN jet definition) are generated in the hard process, "inclusive" means n hard jets and more (usually one extra jet is correctly simulated by the parton shower). After the showering evolution the number of jets does not necessarily match with this number anymore!

• To cover a complete multijet sample, you have to run over over all exclusive samples + highest bin inclusive (taking into account their respective cross sections).

-- Main.felzmann - 01 Jan 2007