The Example Exotica Analysis with PAT

Introduction

This page describes the example exotica PAT analysis tool which was developed for the bprime analysis. The analysis details (physics part) can be found in the following links:

• Main analysis twiki page
• Documented analysis with 1_8_4 fast simulation:
  • Analysis note: CMS AN-2008/064
  • PAS: PAS EXO-08-009

Release for 2_2_X (new/beta)

This version is under test, please refer to the 1_8_4 release if you only want to find an example code. The updated version for 2_2_X (tested under 2_2_6 + patches currently) can be found at /afs/cern.ch/user/k/kfjack/public/bprimeKit/2_2_X.

For the PAT part, it works with the 2_2_6 release. See the PAT recipes for details SWGuidePATRecipes for 2_2_X.

A copy-and-paste guide

Go to a working directory, and prepare the CMSSW environment:

scramv1 project CMSSW CMSSW_2_2_6
cd CMSSW_2_2_6/src/

Access the full source tar ball at /afs/cern.ch/user/k/kfjack/public/bprimeKit/2_2_X/fullsrc.tar.gz

tar xfvz fullsrc.tar.gz

Then, compile the code (it will take a while, if the PAT tags are included):

scramv1 b

The script MyAna/bprimeKit/test/full.py is the example script for the analyzer. (full.py for Summer08 fullsim, fast.py for 2_2_X fastsim, pattuple.py for 2_2_X PATTuples.)

cd  MyAna/bprimeKit/test/
cmsRun full.py

A root file, results_full.root will be generated.

How to generate a simple physics plot

This is an example for how to access the results_full.root. Two files are needed:

• Tree format definition: /afs/cern.ch/user/k/kfjack/public/bprimeKit/2_2_X/format.h
• Example root code: /afs/cern.ch/user/k/kfjack/public/bprimeKit/2_2_X/proj.cc

root -l proj.cc

And it will generate a simple plot for the p_T of jets. Please read the format.h for the detailed information of the root trees.

Release for 1_8_4

This analysis tool, bprimtKit, is running under CMSSW_1_8_4 together with the single snapshot PAT (See SWGuidePATRecipes for 1_8_X). Since 1_8_4 PAT is not fully supported, some features have to be switched on by the users. Here are a short summary on the modifications:

• Switch on the cut based electron (robust) ID. The muon ID by the global function muonid::isGoodMuon() is directly called by the analysis code instead of PAT interface.
• The jet correction in 1_8_4 PAT is off (and with only the MCJetCorrections). The producer JetCorrFactorsProducer is modified to include the recommended L2+L3 jet corrections. The L5 flavor dependent correction is not used (leaving the space for extension).
• The MET correction is also modified accordingly (replace the MCJet by L2+L3).
• The originalObjectRef() links are not working well in 1_8_4 PAT. In order to retrieve some of the information that are only stored in the original RECO object, some additional codes are added in order to by-pass the problems (a matching with dR and Pt).
• We added jet and primary vertexes association (through the algorithm 1, alpha cut).

Quick start

Here we describe the recipe for a quick start with bprimtKit:

Go to a working directory, and prepare the CMSSW environment:

scramv1 project CMSSW CMSSW_1_8_4
cd CMSSW_1_8_4/src/

Access the full source tar ball at /afs/cern.ch/user/k/kfjack/public/bprimeKit/1_8_4/fullsrc.tar.gz This tar ball includes the original 1_8_4 PAT snapshot, the bprimtKit source code, and the modifications listed above.

tar xfvz fullsrc.tar.gz

Then, compile the code (it will take a long time for PAT tools)

scramv1 b

The script MyAna/bprimeKit/test/test_all_in_one.cfg is the example script for the analyzer.

cd  MyAna/bprimeKit/test/
cmsRun test_all_in_one.cfg

It will produce a root tree stored in the root file, results.root. See the recipe below for how to produce some fastsim MC for testing the code. Also, for how to generate a physics plot from this results.root can be found below as well.

Produce some b'->tW fast simulation MC for a simple test

Initial another CMSSW_1_8_4 working environment (IMPORTANT: The MC production cfg conflicts with the PAT environment.)

scramv1 project CMSSW CMSSW_1_8_4
cd CMSSW_1_8_4/src/

Get my template production cfg file prod_template.cfg, and the cfi for b'->tW pythia setup bprime_tW_m300.cfi. Run the production cfg and it will produce 10 b'->tW signal events.

cmsRun prod_template.cfg

How to generate a simple physics plot

This is an example for how to plot jets' p_T stored in the results.root. Two files are needed:

• Tree format definition: /afs/cern.ch/user/k/kfjack/public/bprimeKit/1_8_4/format.h
• Example root code: /afs/cern.ch/user/k/kfjack/public/bprimeKit/1_8_4/proj.cc

root -l proj.cc

And it will generate a simple plot for the p_T of jets (with energy corrections). Please read the format.h for the detailed information of the root tree produced by bprimeKit.

-- KaiFengChen - 31 Oct 2008