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Useful links



  • Z+jets plots "blessed" for conferences (new): link
  • WZjetsCSC notes and plots

Object ID

Electron Reconstruction

  • Short description and Documentation
  • More details about the Electron ID
    • AOD electron :
      • Sliding Window Clusters in 5x5, 3x5 and 3x7
      • Clusters corrected for position and energy modulations
      • Separation of Electron and Photon candidates by a simple track match: DEta<0.025 , DPhi<0.05; E/p<4
      • Hadronic activitity < 20%
    • Is EM is calculated (no cut applied in AOD), using information about the Hadronic Leakage, the lateral shower shape in the second sampling of the EM Calorimeter, the lateral shower shape in the strips, the track Quality Cuts (# of hits and impact parameter), the track-calorimeter spatial matching, E/p and the fraction of high threshold TRT hits
    • The electron likelihood parametrizes the distributions of various discriminating variables for signal (S) and background (B) which are then interpreted as PDFs. The signal probability S ( or em Weight) and the background probability B (or pion Weight) are calculated as a product of the individual probabilities. The final discriminant is the likelihood ratio S/(S+B). The ATLAS electron likelihod uses e0/e, e1/e, e2/e, e3/e, Et Cone40/et, E237/E277, E233/E237,et/(et+Etha), e/p, deta1, dphi2, zvertex/errz, Weta1, Weta2, E2tsts1-Emins1, Fracs1, Isol and numtracks (see documentation of vaiables )

Muon Reconstruction

  • Muon Identification
    • STACO (STAtistical COmbination) is Saclay product which attempts to statistically merges the two independent measurements derived from the inner detector track with the spectrometer track at the IP.
    • MuIDCombined (written (in C++) by Alan Poppleton). Unlike STACO which statistically merges the two independently found tracks, this code performs a global refit of all hits associated with these tracks, taking into account the calorimeter mass profile which is approximated by two scattering planes.
  • Documentation

Jet Reconstruction

MC data sets

  • Pythia Z-> leplep inclusive
    • Documentation
    • Z->ee: 5144 trig1_misal1_csc11.005144.PythiaZee.recon.AOD.v12000601
    • Z->mumu: 5145 trig1_misal1_csc11.005145.PythiaZmumu.recon.AOD.v12000601
    • Z->tautau->lep: 5146 trig1_misal1_csc11.005146.PythiaZtautau.recon.AOD.v12000601
  • Higgs group Z+jets Loose samples:
    • Information:
    • ID 8130 .... 8135 (0 jets .... >=5 jets)
    • atlfast samples: /castor/cern.ch/grid/atlas/users/jtanaka/HiggsWG/Z_samples/fast/CBNT/
    • fully reconstructed Zee: trig1_misal1_mc12.008131.AlpgenJimmyZeeNp1LooseCut.recon.AOD.v12000601 etc.
    • fully reconstructed Zmm: trig1_misal1_mc12.008143.AlpgenJimmyZmumuNp1LooseCut.recon.AOD.v12000601 etc
  • Alpgen Susy background: Z->nunu
    • Information: ZplusJetsAlpgen
    • ID: 8124 ... 8129
    • atlfast samples (directory contains also other SUSY background ): /castor/cern.ch/grid/atlas/datafiles/susy/atlfast/2006_b
  • QCD background
    • for Zmm: trig1_misal1_mc12.017506.PythiaB_bbmu6mu4X.recon.AOD.v12000601
    • for Zee: trig1_misal1_mc12.005802.JF17_pythia_jet_filter.recon.AOD.v12000601
  • Pythia SUSY background

Zmumu+jets analysis

TTbar semi-leptonic

MC samples

  • J2 - location - size - cross section - FLIPA tag
  • J3 - ..
  • ...

cuts used

  • in FLIPA:
    • electron:
      • pT > 10 GeV
      • |eta| < 2.5
      • isolation < 6 GeV
      • isMediumEM
    • muon:
      • pT > 20 GeV
      • |eta| < 2.5
    • jets:
      • pT > 10 GeV
      • |eta| < 2.5

  • in the analysis:
    • electron:
      • # of electrons > 0
      • pT > 30 GeV
      • isMediumEM()
      • etcone20 < 6 GeV
      • \Delta R (ele, jets) > 0.3 for jets with pT ratio > 0.5
    • muon:
      • # of muons > 0
      • pT > 30 GeV
      • fit \Chi^2 < 200
      • match \Chi^2 < 100
      • nucone20 < 3
      • etcone20 < 2 GeV (etcone bug?!)
      • \Delta R (muon, jets) > 0.3 for jets with pT ratio > 0.5
    • jets:
      • 1^{st} jet pT > 65, 2^{nd}, 3^{rd}, and 4^{th} jet pT >40 GeV
      • |eta| < 2.5

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/cern.ch/grid/atlas/users/ashibata/cscpre12-5104
    • Z->tautau: 5188 = /castor/cern.ch/grid/atlas/users/ashibata/cscpre12-5200
    • ttbar: 5200 = /castor/cern.ch/grid/atlas/users/ashibata/cscpre12-5200
    • single top: 5501 = /castor/cern.ch/grid/atlas/users/ashibata/cscpre12-5200
  • 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 TopViewAANtuple.new.root has been obtained merging the 2 other files.

TopView ntuples


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/TopViewInserters_module.py . 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


Tau1p3p is the preferred Tau reconstruction method for the ttbar reference sample
The tau1P3P algorithm is dedicated for reconstruction and identification of the hadronic tau's with visible energy from hadronic decays in the range 20 - 70 GeV, it is track-based, with energy-scale given by energy-flow approach.






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/atlas-data02/scratch/AtlasSoftware/EVgroupArea/EventView-$CMTPATH
Future updates can be installed in the same EVgroupArea directory using pacman

  • Using Pacman at PIC
Let say you want to install EventView-$Release at PIC. First configure pacman:
      * cd /nfs/atlas-data02/scratch/AtlasSoftware/pacman/pacman-$VERSION
      * source setup.sh
Then go to the EV groupArea directory and create a new directory for the desired version
      * cd /nfs/atlas-data02/scratch/AtlasSoftware/EVgroupArea/
      * mkdir EventView-$RELEASE
      * cd EventView-$RELEASE
and execute the pacman command:
      * pacman -v all -get http://atlas-computing.web.cern.ch/atlas-computing/links/kitsDirectory/PAT/EventView/:EventView-$RELEASE.pacman

Installing a production patch at PIC*

Setup the athena release and pacman:
   * source $VO_ATLAS_SW_DIR/software/12.0.6/setup.sh
   * source /nfs/atlas-data02/scratch/AtlasSoftware/pacman/pacman-$VERSION/setup.sh

Then do

pacman -get http://cern.ch/atlas-computing/links/kitsDirectory/Production/cache:patch-name
The list of availables patches can be found at: http://atlas-computing.web.cern.ch/atlas-computing/links/kitsDirectory/Production/cache/


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

Topic attachments
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This topic: Main > IFAEAtlasAnalysis
Topic revision: r78 - 2008-12-01 - VolkerVorwerk
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