Search for High-Mass Diphoton Resonances - Analysis Page

THIS PAGE IS OUTDATED. PLEASE GO TO: ExoticaDiphotonResonance

• Conor Henderson, Toyoko Orimoto (CERN)
• Yousi Ma (Caltech)
• Sean Simon (UCSD)

CADI Entry EXO-10-019

http://cms.cern.ch/iCMS/analysisadmin/viewanalysis?id=410&field=id&value=410&name=Search%20for%20Randall-Sundrum%20Gravitons%20in%20the%20Diphoton%20Channel%20in%20pp%20Collisions%20at%20sqrt%28s%29%20=%207%20TeV

Documentation:

Analysis Note AN-10-405 & PAS EXO-10-019

http://cms.cern.ch/iCMS/jsp/db_notes/showNoteDetails.jsp?noteID=CMS%20AN-2010/405

Instructions for checking out note:

• https://twiki.cern.ch/twiki/bin/view/CMS/Exotica2010WinterResonances

To make a tag:

•  svn copy svn+ssh://svn.cern.ch/reps/tdr2/notes/AN-10-405/trunk svn+ssh://svn.cern.ch/reps/tdr2/notes/AN-10-405/tags/toyoko_061210 

Recent Presentations

• Status report, Exotica Resonances, 12 Nov 2010
• Status report, Exotica Resonances, 3 Sept 2010
• First look at diphotons in data, Exotica Photons, 11 June 2010
• 7 TeV Scaling, Exotica, 09 March 2010
• Overview, Resonances Meeting, 06 November 2009

Earlier Results

• "Search for Randall-Sundrum Gravitons in the Diphoton Final State", Summer 2009
• "Search for Randall-Sundrum excitations of gravitons decaying into two photons for CMS at LHC", CMS NOTE-2006/051

Based on the earlier MC approved analysis EXO-09-009, our expected sensitivity after scaling to 7 TeV is shown here:

Previous publications from the Tevatron experiments on this topic:

• CDF publication with 5.4 pb-1
• D0 publication with 5.4 pb-1
• CDF publication with 1 pb-1
• D0 publication with 1 pb-1

Analysis Code

The base directory for our analysis code package is: http://cmssw.cvs.cern.ch/cgi-bin/cmssw.cgi/UserCode/ExoDiPhoton/DiPhotonAnalysis/

A simple filter to preselect events with at least two reco::Photons (with configurable pt cuts) is in: DiPhotonFilter/

The analysis code for running on data is in: ExoDiPhotonAnalyzer/. Likewise, the code for running on signal MC and background MC are in ExoDiPhotonSignalMCAnalyzer and ExoDiPhotonBkgAnalyzer, respectively. Common header classes are defined in CommonClasses.

The idea is that, for our current relatively small datasets, we basically would like to go directly from RECO to histograms. The output of the analyser is just a basic tree, with information on the two highest-pT reconstructed photons which pass our tight photon ID and spike-removal cuts. The final histograms are then filled directly from these trees.

Tags

Event and Photon Selection

Event Selection

For basic event selection, we use the standard 'Good Vertex' and 'No Scraping' filters, as detailed in the Collisions 2010 twiki and links within (Note that we use a data vtx z-range of +-24cm, following a Physics Operations email of 5 August 2010)

More details can be found below at: https://twiki.cern.ch/twiki/bin/view/Main/DiPhotonResonanceAnalysis#Third_Processing

Kinematic Requirements

• Photons pT > 30 GeV
• Photon |eta| < 2.5
• Photon |eta| < 1.4442 && Photon |eta| < 1.566 (excluding EB-EE gap)

Photon ID

For Photon ID, we use the recommended E-Gamma Tight ID selection:

• Had/EM < 0.05
• ecal Iso (cone 0.4) < 4.2 + 0.006*pt
• hcal Iso (cone 0.4) < 2.2 + 0.0025*pt
• track Iso (cone of 0.4) < 2.0 + 0.001*pt
• sigma ieta ieta < 0.013 (EB), < 0.030 (EE)
• require No Pixel Seed

Spike cleaning procedure:

Spikes are automatically cleaned in the 38X series and beyond.

• https://twiki.cern.ch/twiki/bin/viewauth/CMS/SWGuideEgammaSpikeCleaning

Scripts for CRAB jobs

We've written some scripts to ease launching many jobs (for instance, many MC samples) to the GRID. They have been committed to DiPhotonAnalysis/ExoDiPhotonBkgAnalyzer/test/. They are currently set up to run on /*/Spring10-START3X_V26_S09-v1/GEN-SIM-RECO MC, but can easily be adapted to run on other samples.

Click here to see detailed instructions hide

 ./launchDiphoton.sh DiPhotonBox_Pt250toInf 

Code/Scripts for Making Histograms

We've also written some ROOT code and scripts for making plots. They have been committed to DiPhotonAnalysis/ExoDiPhotonBkgAnalyzer/test/plots/. They run on the files stored in /castor/cern.ch/user/t/torimoto/physics/diphoton/ntuples/mc/.

Click here to see detailed instructions hide

 .L fTree.C++; 

 ./plotDiphoton.sh  DiPhotonBox_Pt250toInf 

To-Do List for Next Re-Processing

• Ideas for further improvements:
  • save every RECO photon with pT > 30 GeV ?
  • Utilize wider gap (from Sean's Photon ID optimization studies)
  • use E2/E9 for spike removal

Summary Plots

Data

• http://torimoto.web.cern.ch/torimoto/physics/diphoton/data/Data_38X_V3/data_33.9pb_onlyEB/
  
• http://torimoto.web.cern.ch/torimoto/physics/diphoton/data/Data_38X_V3/DataMC_33.9pb_onlyEB/
  

MC Background

• http://torimoto.web.cern.ch/torimoto/physics/diphoton/mc/MC_36X_V4/allMC_33.9pb_onlyEB/
  

NB: All plots have required the selection described above

Data

Show Outdated Processing hide

Third Processing

updated to 38X to use sept17re-RECO (spike cleaning included) and also to read Run2010B data (RECO's in 38X).

event selection includes:

process.primaryVertexFilter = cms.EDFilter("GoodVertexFilter", vertexCollection = cms.InputTag('offlinePrimaryVertices'), minimumNDOF = cms.uint32(4), maxAbsZ = cms.double(24), maxd0 = cms.double(2) )

process.noScraping = cms.EDFilter("FilterOutScraping", applyfilter = cms.untracked.bool(True), debugOn = cms.untracked.bool(False), numtrack = cms.untracked.uint32(10), thresh = cms.untracked.double(0.25) )

process.diphotonFilter.ptMin_photon1 = 10.0

process.diphotonFilter.ptMin_photon2 = 10.0

Fourth Processing

Includes second vtx dependent calculations from conor (empty branches are not intialized...)

Event displays

Event Displays of high mass diphoton events can be found at: https://twiki.cern.ch/twiki/pub/Main/DiPhotonResonanceAnalysis/Mgg_eventdisplays_ym.ppt

Older Event Displays hide

MC: RS Graviton Signal

RS graviton signal samples have been generated from a range of different points in the k/Mpl vs M plane:

Signal MC Samples hide

MC: Background

Locations of ntuples: /castor/cern.ch/user/t/torimoto/physics/diphoton/ntuples/mc/

Background MC Samples hide

Limit-setting & Sensitivity Studies

We use the CMS Exotica supported package (ExoSt) for producing limits: https://twiki.cern.ch/twiki/bin/view/CMS/ExoSt

We also use the "95 percent Confidence Level Limit Calculator" from the Exotica group.

Other Useful Information

Spring2010 MC Twiki: https://twiki.cern.ch/twiki/bin/viewauth/CMS/ProductionReProcessingSpring10

Fall2010 MC Links:

• Requests: https://twiki.cern.ch/twiki/bin/view/CMS/ProductionFall2010
• Status: http://vdutta.web.cern.ch/vdutta/Fall10ProductionRECOglobal.html
• Status: http://ceballos.web.cern.ch/ceballos/production/Fall10ProductionRECOglobal.html

EventNumberFilter: for selecting individual events, given a run

• EventNumberFilter.cc
• eventNumberFilter_cfi.py
• To check out code:

   cvs co -d CaloOnlineTools/EventNumberFilter/ UserCode/CCEcal/CRUZET2/CaloOnlineTools/EventNumberFilter/ 

EventDisplays: Fireworks & iSpy/Iguana

• More Info Here
• Example iSpy config file

-- ConorHenderson - 03-Jun-2010

• RS_evt1.pdf: event display, EB only

• RS_evt2.pdf: event display #2, EB only

• RS_evt3.pdf: event display #3, EB only