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Object ID

Electron Reconstruction

  • Short description and Documentation
    • I'm starting documentation in EventViewElectronDetailed, but this will take some time..
    • As long as the CSC note is not finished, the best EMID documentation can be found in the EgammaATLASRecoPerformance page. Here you can find the link to the most recent performance note.
    • A complete list of the AOD content can be accessed from the Class references in the AOD pages
    • A project to document the AOD content has started (Kevin Black). So far the mosy useful documentation is the EgammaCBNT page and the documentation of the most important Electron Variables produced by the EV calculators in 12.0.x
    • Electron candidates are separated in reconstruction from Photon candidates by applying a loose track match. The default electron ID uses isolation in a hollow 0.45 cone and the IsEM flag which is composed of bits that correspond to various requirements on the shower shape in the calorimeter and the track in the ID. The IsEM flag is described in ElectronGammaIsEM page. Alternative approaches using multivariate techniques (NN, Likelihood, HMatrix, ..) are in advanced stage of development.
    • A good source of information are also various recent talks in the EMID group
  • Overview: Default Electron ID (cut-based)
    • Sliding Window Clusters in 5x5, 3x5 and 3x7
    • Clusters corrected for position and energy modulations
    • Separation of Electron and Photon candidates by SimpleTrack Match: Matching criteria : DEta < 0.025 , DPhi < 0.05; E/p < 4
    • Hadronic activitity < 20%
    • IsEM calculated (no cut applied in AOD), using
      • Hadronic Leakage
      • Lateral shower shape in second sampling of EM Calorimeter
      • Lateral shower shape in strips
      • Track Quality Cuts (# of hits and impact parameter)
      • Track Calorimeter spatial matching
      • E/p
      • Fraction of high threshold TRT hits

Muon Reconstruction

Jet Reconstruction

MC samples

  • Pythia Z-> leplep inclusive
    • Z->ee: 5144 /castor/
    • Z->mumu: 5145 /castor/
    • Z->tautau: 5146 /castor/
  • Higgs group Z+jets Loose samples:
    • generation conditions:
      • Parton CUT Pt>20GeV eta < 6
      • Factorization Q^2=Mz^2+sum_Pt^2_of jet (but due to ALPGEN bug Factorization Q^2=Mz^2+ (Pt^2_of Z))
      • renormalization each PT
      • PT_lep>5GeV eta < 3
      • Mll=40-200GeV
    • Event Filter:
      • ele or mu: N>=2(ee,mumu)>=1(tautau) with Pt>10GeV, |eta|<2.7
      • truth jet(Cone4TruthJets): N>=1 with Pt>20GeV, |eta|<5.0
    • Information: ZplusJetsAlpgen
    • ID 8130 .... 8135 (0 jets .... >=5 jets)
    • atlfast samples: /castor/
  • Alpgen Susy background: Z->nunu
    • Information: ZplusJetsAlpgen
    • ID: 8124 ... 8129
    • atlfast samples (directory contains also other SUSY background ): /castor/


TTbar-> tau

MC samples

  • Top MC samples are defined here. Any sample reconstructed with release 11 can found at panda monitor. Production with release 12 is on going, not much was produced until now (for Top analysis), however some few AODs were reconstructed by Elzbieta, and can be found at:
    • W->e nu: 5104 = /castor/
    • Z->tautau: 5188 = /castor/
    • ttbar: 5200 = /castor/
    • single top: 5501 = /castor/
  • And replicated at pic at:
    • /nfs/atlas-data03/cosuna/official_data/cscpre12/csc11.005200.T1_McAtNlo_Jimmy.digit.RDO.v11004205
  • As the statistics for rel12 is not enough, we reconstructed more events (running on rel11 digit files) and placed them under:
    • /nfs/atlas-data03/cosuna/official_data/cscpre12/csc11.005200.T1_McAtNlo_Jimmy.digit.RDO.v11004205_IFAE
  • Ntuples produced with the leptonic W's daughter-number fix are placed under:
    • /nfs/atlas-data03/fiorini/cspre12/ntuples has been obtained merging the 2 other files.

TopView ntuples

  • Ongoing detailed documentation on ntuple variables.
  • For a full description of ntuple variables: Truth, Reco. Another description (should be the "official") here.
  • release 11. Large TopView athena aware ntuples were produced with release 11.
  • release 12. Few files were produced for release 12 (and TopView-00-12-xx ) for validation. With this release two types of AAN are being generated, depending on the type of tau identification algorithm used (tauRec or tau1p3p):
    • /castor/


B tagging is done by default combining the results of 2 different algorithms: IP3D and SV1.
  • IP3D calculates with tracks informations the 3-D impact parameter (d) of a b vertex candidate and its significance: s = d/sigma(d).
  • SV1 reconstructs secondary vertices in the BJet. SV1 algorithm uses a bottom-up approach: it fits vertices with all pairs of tracks, retaining the fit with the highest probability and fitting the remaining tracks of the jet to this vertex. All tracks below a certain fit probability will be rejected. A likelihood variable is calculated with the secondary vertex parameters (mass, fit probability, multiplicity and distance from the reconstructed primary vertex).
  • The two informations are summed in a bjet weight variable, that is variable used to discriminate bjets from other jets. The standard cut on the weight is at value of 3 (b-tagged jets having a weight greater than 3). The cut can be changed in TopView inside python/ . The default tagging algorithm has an efficiency of 60% and a Rejection factor for light jets of 240 in ttjjenu and ttH events.
  • More details are available at BTagging Homepage and the main BTagging algorithm is in CVS under: PhysicsAnalysis/JetTagging/JetTagAlgs/BTagging
  • ...

EV groupArea at PIC.

The PAT group is continuosly developing and applying patched to official atlas releases, even when the release is out. Therefore they make use the so called groupArea, where they install updates packages that will overload the default packages to be found in the release. In order to use the latest EV, SUSYView, TopView,... we need to install a given EVTag at PIC (exactly in the same way as they do in groupArea at CERN). There are several ways one can do that (consult here), but the easiest and faster is to use pacman.

I installed the latest EV version at:

In order to use this area, prepend this path to your CMTPATH before running athena:
export CMTPATH=/nfs/$CMTPATH
Future updates can be installed in the same EVgroupArea directory using pacman

  • Using Pacman at PIC
Let say you want to install EventView-$Release at PIC. First configure pacman:
      * cd /nfs/$VERSION
      * source
Then go to the EV groupArea directory and create a new directory for the desired version
      * cd /nfs/
      * mkdir EventView-$RELEASE
      * cd EventView-$RELEASE
and execute the pacman command:
      * pacman -v all -get$RELEASE.pacman


Under this section are stored some interesting documents, talks and lectures that you can find helpful to consult during your analysis:
Major updates:
-- UllaBlumenschein - 09 Jan 2007 -- Main.cosuna - 09 Jan 2007

%RESPONSIBLE% Main.unknown

%REVIEW% Never reviewed

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