PH4100 MSci Project - Simulated event samples

General comments

All samples for this project are simulated at a centre-of-mass energy of 13 TeV and correspond to the 2017 configuration for both the ATLAS detector and the LHC.

(Technical details: August 2019 ntuple production, with release 21.2.86; L2 ntuples, i.e. small ntuples, only 308 variables. Ntuple production was done by Dave Thomas in November/December 2019. All the necessary weights are already included in the ntuples. This includes, specifically, weight_normalise, therefore no need to calculate it on the fly.)

The samples are specifically for the ttH (H-bb) dilepton channel analysis, and are pre-selected by number of leptons (2), number of b-tagged jets at 85% working point, etc.

The samples are all available on linappserv from the directory

/scratch2/ptd/ATLAS/MC2017-new/

The specific samples for this project are in the following root files:

  28844653644 Nov 25  2019 ttH_PoPy8_FS_17.root
 113789188425 Nov 25  2019 ttbar_PP8_dil_AFII_17.root
  14294844001 Nov 26  2019 ttbb_AFII_17.root
    579382465 Nov 25  2019 singletop_FS_17.root
   7258968528 Nov 25  2019 ttV_FS_17.root
    322521794 Nov 25  2019 ttWW3t4t_tWZ_FS_17.root
      9473426 Nov 25  2019 Wjets_FS_17.root
   2987049890 Nov 25  2019 Zjets_FS_17.root
    497478705 Nov 25  2019 diboson_FS_17.root

In these filenames:

  • "FS" indicates Full Simulation of the ATLAS detector
  • "AFII" indicates Fast Simulation (ATLFAST II) of the ATLAS detector
  • "17" indicates 2017 configuration

Signal sample: ttH

  28844653644 Nov 25  2019 ttH_PoPy8_FS_17.root

The signal sample was generated with PowHeg + PYTHIA 8, and it includes all Higgs decays.

Specific Higgs decays can be selected using the information given here: selecting a specific Higgs decay mode.

(This sample includes 3 DSIDs: mostly events from 34345 ("2l"), but also some events with two reconstructed leptons from 346343 ("0l") and 346344 ("1l").)

Background samples

ttbar

 113789188425 Nov 25  2019 ttbar_PP8_dil_AFII_17.root

The ttbar background consists of a top + anti-top quark pair, with additional jets. The sample was generated with PowHeg + PYTHIA 8 (5FS = five-flavour scheme). Note that "dil" in the filenames does not mean that only the dilepton final state was generated; it means that these are the ntuples for the dilepton analysis. This sample includes all of tt + light jets, tt + c-jets and tt + b-jets. The channels included in this sample are: "all hadronic", "non-all hadronic" and "dilepton"; the first two are orthogonal samples, but "non-all hadronic" includes "dilepton" events. For the dilepton analysis there are two main options: either use just the "dilepton" DSIDs, or use all three channels; for the latter it is therefore necessary to remove overlapping dilepton phase space - this is done using the truth_top_dilep_filter variable in the ntuples.

tt+bb

  14294844001 Nov 26  2019 ttbb_AFII_17.root

This is a dedicated sample for the production of a top-antitop-quark pair plus a b and anti-b pair (4FS = four-flavour scheme). If this sample is used (which is recommended, as this is the main background) the overlap with the tt+bb events already included in the "ttbar" sample above has to be removed. This is done using the HF_SimpleClassification variable in the ntuples.

single top

    579382465 Nov 25  2019 singletop_FS_17.root

Single top-quark production.

ttV

   7258968528 Nov 25  2019 ttV_FS_17.root

Production of a top + anti-top-quark pair with an associated gauge boson (V = W or Z).

ttWW3t4t

    322521794 Nov 25  2019 ttWW3t4t_tWZ_FS_17.root

This sample includes several rare processes with top-quarks: ttWW, 3t and 4t, as well as tWZ.

W+jets, Z+jets

      9473426 Nov 25  2019 Wjets_FS_17.root
   2987049890 Nov 25  2019 Zjets_FS_17.root

Production of a single W or Z gauge boson, with additional jets.

di-boson

    497478705 Nov 25  2019 diboson_FS_17.root

Production of two heavy gauge bosons: WW, WZ and ZZ.

-- Pedro Teixeira Dias - 01 Dec 2020

Comments

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Topic revision: r1 - 01 Dec 2020 - PedroTeixeiraDias

 
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