Two-lepton/four-lepton analysis example of CMS 2011 open data

Rodriguez Marrero, Ana ; Lassila-Perini, Kati ( Helsinki Inst. of Phys. )

Cite as: Rodriguez Marrero, Ana; Lassila-Perini, Kati; (2016). Two-lepton/four-lepton analysis example of CMS 2011 open data. CERN Open Data Portal. DOI:10.7483/OPENDATA.CMS.3E87.48PZ

Data recorded in 2011 and published in 2016

Software Analysis CMS CERN-LHC

Description

Example code for a simple analysis on Z decays to two leptons and ZZ decays to four leptons, of CMS open data.

Running the job over all preprocessed datasets may take several hours.

Use with

Use this with the following datasets:

Muons and electrons in PAT candidate format derived from /DoubleMu/Run2011A-12Oct2013-v1/AOD primary dataset

Muons and electrons in PAT candidate format derived from /DoubleElectron/Run2011A-12Oct2013-v1/AOD primary dataset

Characteristics

1 file.

System details

Use this code with the CMS Open Data VM environment for 2011 open data
Software release: CMSSW_5_3_32

CMS VM Image, for 2011, 2012 and 2015 CMS open data

External links

https://github.com/cms-opendata-analyses/OutreachExercise2011/tree/v.1.1.1

Data selection

The event selection is the same as the one used in 2010 example:

In the Z analysis at least two leptons with opposite charge, with invariant mass ”mll” between 12 GeV and 120 GeV are required. The pair with the invariant mass closest to the Z boson mass is selected as the Z candidate.
In the ZZ analysis two Z candidates are required, and for both candidates, two leptons with opposite charge are required. The first Z candidate is required to have higher lepton momentum: 20 GeV for the first lepton and 10 GeV for the second lepton. The invariant mass is required to be in the range 40 GeV to 120 GeV. The second candidate is required to have an invariant mass higher then 4 GeV. The first candidate is the one with the invariant mass closest to the Z boson mass.

Selection criteria for electron candidates:

pT > 7 GeV and |η| < 2.5;
Distance between the electron z-vertex and the interaction z-vertex < 0.2 cm;
Transverse impact parameter w.r.t. the beam spot < 0.04 cm;
Symmetrised impact parameter w.r.t. the beam sport < 4 cm;
Photon conversion rejection: number of lost hits in the tracker < 1;
Electron identification: eIDLoose;
Electron Isolation depends on the η region, regions with 1.44 < η 0.09; electron.dr03EcalRecHitSumEt()/electron.pt() > 0.07; and electron.dr03HcalTowerSumEt()/electron.pt() > 0.10. If η > 1.57: electron.dr03TkSumPt()/electron.pt() > 0.04; electron.dr03EcalRecHitSumEt()/electron.pt() > 0.05; and electron.dr03HcalTowerSumEt()/electron.pt() > 0.025. Each component is computed from Isodeposits in a cone of 0.3 around the electron direction.

Selection criteria for muon candidates:

pT > 5 GeV and |η| < 2.4;
Distance between the muon z-vertex and the interaction z-vertex < 0.2 cm;
Is a GlobalMuon and TrackerMuon;
Number of valid hits in the inner tracker > 10;
χ2 /ndo f < 10 for the global muon fit;
Transverse impact parameter w.r.t. the beam spot < 0.02 cm;
Symmetrised impact parameter w.r.t. the beam sport < 4 cm;
Relative Muon Isolation (RMI) < 0.15, with RMI = (ChargedHadronIso + NeutralHadronIso + PhotonIso)/pT(µ)

Each component is computed from Isodeposits in a cone of 0.3 around the muon direction.

Validation

The input files contain only the validated runs for primary datasets of 2011. For user validation of the analysis step, compare the result to the expected output file.

CMS list of validated runs Cert_160404-180252_7TeV_ReRecoNov08_Collisions11_JSON.txt