Single diffractive W software page

Complete: 2

Introduction

This page describes the software and steps used in the analysis of "Single-diffractive W production", within the Forward PAG. For the physics description look here.

Versions & Tags

The following tags are currently used for the analysis, on top of CMSSW_2_2_X:
   cvs co -r V03-03-00      DiffractiveForwardAnalysis/CMS.SingleDiffractiveWAnalysis
   cvs co -r V00-00-01      DataFormats/CMS.CastorReco
   cvs co -r V00-01-00      FastSimulation/ForwardDetectors
   cvs co -r V00-01-00      RecoLocalCalo/Castor
   cvs co -r V01-00-01      SimDataFormats/GeneratorProducts
   scramv1 b
   

Analysis chain

The analysis is made as modular as possible. It'll generally consist of two steps: a first sample reduction where most of the processing of new variables and collections will be made, saving only events satisfying a given selection and all the relevant information in EDM format. A second step will consist in analyzing these reduced (skimmed) samples and producing the final histograms and plain n-tuples for further inspection & plotting.

An example configuration file can be found here. The main sequences are defined in DiffractiveForwardAnalysis/SingleDiffractiveWAnalysis/python/analysisSequences_cff.py, which imports and defines the event selection sequence, as well as a simple analyzer to be run before and after the selection. Also imported is a edmDumpSequence, which defines a number of extra collections and variables produced. The paths and sequences defined in analysisSequences_cff are:

wmunuAnalysis = cms.Path(wmunuAnalyzer)
wmunuAfterFilter = cms.Path(wmunuSelFilter*wmunuAnalyzerAfterFilter)

wmunuSelectionSequence = cms.Sequence(wmunuSelFilter)
edmDumpSequence = cms.Sequence(wmunuSelFilter*genParticlesCalo*edmDumpAllNoPileUp)

plus optionally a number of analyzers for different pile-up conditions.

Python fragment: link

Event selection

The events are selected using the WMuNuSelector, which can be obtained from the ElectroWeakAnalysis/WMuNu package.

wmunuSelFilter

Python fragment: link

Description: Defines the filter used the event selection.

Imported/defined at: analysisSequences_cff

Tracks selection

Inside DiffractiveForwardAnalysis/SingleDiffractiveWAnalysis/python/edmDump_cff.py, a few modules are defined to select and write in the event a subset of tracks of interest. The saved products are:

selectGoodTracks

Python fragment: link

Description: Selects tracks according to quality criteria.

Imported/defined at: edmDump_cff

selectTracksAssociatedToPV

Python fragment: link

Description: Select tracks associated to primary vertex (defaults modified in edmDump_cff).

Imported/defined at: edmDump_cff

selectTracksAwayFromPV

Python fragment: link

Description: Select tracks away from (not associated to) primary vertex (defaults modified in edmDump_cff).

Imported/defined at: edmDump_cff

"EDM variables"

A number of extra variables are additionally saved back in the event with the aim of advancing some of the processing associated to the analysis as well allowing to discard some collections in an intermediary step. The saved products are:

castorGen/castorGenNoThreshold

Python fragment: link

Description: Produces generator level information for the energy deposits and multiplicity of Castor sectors above threshold. Only geometrical acceptance is taken into account.

Imported/defined at: edmDump_cff

castorTower

Python fragment: link

Description: Saves multiplicites and energy depositions for Castor towers, taken from Castor reconstruction.

Imported/defined at: edmDump_cff

hfTower

Python fragment: link

Description: Saves multiplicities and energy deposition for HF towers.

Imported/defined at: edmDump_cff

xiTower/xiTowerNoMET

Python fragment: link

Description: Computes $\xi$ using as input calot towers. Different thresholds are allowed as well as the possibility of including muons and MET.

Imported/defined at: edmDump_cff

xiFromJets/xiFromJetsNoMET

Python fragment: link

Description: Computes $\xi$ using jets as input.

Imported/defined at: edmDump_cff

trackMultiplicity/trackMultiplicityAssociatedToPV/trackMultiplicityAwayFromPV

Python fragment: link

Description: Saves the multicplicity of tracks for each input collection.

Imported/defined at: edmDump_cff

Pile-up

pileUpInfo

Python fragment: link

Description: Saves the number of simulated pile-up events per bunch crossing.

Imported/defined at: edmDump_cff

EdmDumpAnalyzer

The final analysis step runs over all the previously produced variables to obtain the final observables which are either plotted or stored in ROOT TTree format.

edmDumpAnalysis

Python fragment: link

Several copies of the same analyzer are run with different filters (see below), which are used to select events according to simulated information, perform some further selection, select control samples, etc. Some simple python tools to create the different sequences are used from DiffractiveForwardAnalysis/SingleDiffractiveWAnalysis/python/analysisTools.py.

The final result is a ROOT file (saved through the TFileService) with directory for each defined analyzer (control histograms from some filters are also present).

Analysis filters

singleInteractionFilter

Python fragment: link

Description: Selects events with zero pile-up added (simulated).

Imported/defined at: analyzeEdmDump_cfg

singleVertexFilter

Python fragment: link

Description: Selects events with a single reconstructed vertex.

Imported/defined at: analyzeEdmDump_cfg

singleInteractionTMVAFilter

Python fragment: link

Description: Selects events according to a multivariate analysis to identify single-interaction events.

Imported/defined at: analyzeEdmDump_cfg

Analysis Modules

Contact

Responsible: Main.Grzegorz.Brona
Last reviewed by: Never reviewed

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Topic revision: r5 - 2012-01-02 - DavidDEnterria
 
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