Producing Woutuple from AOD

Producing an Ntuple from an AOD

The Ntuple that is produced from the AOD is a dump of most information contained in the AOD. The package that produces an Ntuple from the AOD contains:

• a clone of UserAnalysis/AnalysisSkeleton and
• a clone of AnalysisExamples/ttbar
• the simpleTTbar class that dumps a (nearly) complete ntuple with all AOD information needed for a ttbar analysis on full simulation Monte Carlo

Get the code

1. Go to the directory where you want to install the package and get the code:

TTBarAnalysis.tgz

Setting up the package

1. Go to the directory where you want to install the package and unpack the code:

tar -xzvf TTBarAnalysis.tgz

The package will appear in a subdirectory named TTBarAnalysis of the chosen directory.

1. Go to the cmt directory: cd TTBarAnalysis/cmt
2. Execute cmt config
3. Execute source setup.csh
4. Build the library: gmake

Running the package (an Ntuple from an AOD)

The athena job requires as input the AOD files (also registered in the poolfilecatalogue), the names of the ParticleContainers in the AOD and the name of the output Ntuple. To process a single file called rome.file1.aod.pool.root in the directory /data/atlas/public/Rome/T1/AOD/AOD_Rome/0000/ follow the following steps:

1) If not already done before, go to the cmt directory and execute source setup.csh

2) Go to the run directory: cd /TTBarAnalysis/run

3) The set of AOD files is rather and rather than copying them to the run directory it is easier to create a link to the directory containing them AODs from the run directory. For us at NIKHEF:

 ln -s /data/atlas/public/Rome/T1/AOD/AOD_Eric/ AOD
  

4) Insert the files into the pool file catalog: pool_insertFileToCatalog AOD/0000/rome.file1.aod.pool.root

5) Edit the joboptions file (simpleTTbar_joboptions.py) to steer the job:

• Set the Type of simulation (SimType, see example in joboptions file for details)
• List your AOD file as the input AOD-file (EventSelector.InputCollections)
• Enter the filename of the Ntuple that will be produced (NtupleSvc.Output)

6) Execute: athena.py simpleTTbar_jobOptions.py

An Ntuple called Ntuple_file1.root is produced that can be analysed using the Analysis Skeleton.

Note: All POOL files processed by Athena should be registered in the PoolFile Catalog. Easiest is to register ALL your AODs into the catalog: pool_insertFileToCatalog AOD/*/*AOD.pool.root