This page describes the efforts to make Region of Interest (ROI) in INavigable4Momentum format. This will enable to use them very conveniently in analysis with ROI information.

Why INavigable4Momentum ROIs

Region of Interest information is available via LVL1_ROI container in AOD. It primarily has information about three types of ROIs - Electromagnetic (EM ROI), Muonic (MUROI) and Jet-like (JETROI). Each type of ROI has it's PT threshold, eta and phi associated with it. Further more two special types of ROIs called JetET and Energy Sum are also available. They do not have eta-phi associated with them and hence are termed special in this web page.

For more information on how to access all the ROI information, please have a look at this code in CVS in CBNT_AOD package.

The information on ROI as available from an AOD is not in IParticle or INavigable4Momentum format. Considering the fact that these objects are not particles, this is not completely necessary but not quite.

Each type of ROI has eta and phi associated with it. For DeltaR matching this is the sufficient information but one cannot use the available standard tools for doing DeltaR matching of ROI with particles like electrons, muons and jets because ROIs are not of type IMomentum or INavigable4Momentum. Hence it becomes cumbersome to do simple things with ROIs.

What is needed

It will be helpful to derive ROI from INavigable4Momentum class and fill them with at least PT, eta and Phi information. There are some nice tools available in FourMom package which can also completely fill the IMomentum information for an object provided one supplies PT,Eta, Phi and mass for this object. So if one specifies mass of ROI to be zero then these tools can be used for ROIs.

As a final result one can have INavigable4Momentum ROI objects which then can be used with ease in one's analysis.


This task has been achieved in the following way.

A class called UserINav4Mom is written that helps derive an object with INavigable4Momentum properties in addition with a functionality to completely specify all IMomentum attributes if PT, Eta, Phi and mass attributes for this object are provided.

This class is used to fill EmROI container, MuROI Container and JetROI Container in three separate codes called EmRoiContainer.cxx, MuRoiContainer.cxx and JetRoiContainer.cxx. These containers are like any other container of objects like electrons for example.

One can retrieve ROIs from these containers and use them in their analysis. A modified AnalysisSkeleton code called AnalysisROISkeleton is also provided. To schedule and use these containers code, athena job options file called is also provided.

To use:

  • copy all the header files in UserAnalysis/UserAnalysis directory.
  • Copy all cxx files in UserAnalysis/src directory
  • Modify src/components/UserAnalysis_entries.cxx correspondingly.
  • Edit cmt/requirement to add the following lines
    • use Navigation Navigation-00-* Control
    • use EventKernel EventKernel-00-* Event
    • use FourMom FourMom-00-* Event
    • use NavFourMom NavFourMom-00-* Event
    • use AnalysisTriggerEvent AnalysisTriggerEvent-00-* PhysicsAnalysis/AnalysisTrigger

FourMom package has been updated. For the above recipe to work, please use a FourMom tag greater or equal to 00-00-27

  • cmt co -r FourMom-00-00-27 Event/!FourMom
  • source setup.csh
  • gmake

To compile do:

  • go to cmt directory of UserAnalysis package
  • cmt config
  • source setup.[c]sh
  • gmake

To run :

  • athena | tee test.log

See results:

Browse AnalysisROISkeleton.aan.root file in ROOT and look at variables with ROI in their name. There are four of them. The example illustrates EMROI but it is exactly the same for MUROI and JETROI.

That's it. Hope it is useful.


For Muons, Pt has threshold number * 1000 instead of threshold value. Threshold value is available in 12.0.X series. I will correct this later in the code. If someone is pariticular about it, please correct it. Thanks to Kevin Black for noticing it.

-- VikasBansal - 19 Jul 2006

Topic attachments
I Attachment History Action Size Date Who Comment
Unknown file formatcxx AnalysisROISkeleton.cxx r1 manage 13.6 K 2006-07-19 - 08:20 VikasBansal Ex. -> using EMROI with Electrons
Header fileh AnalysisROISkeleton.h r1 manage 3.6 K 2006-07-19 - 08:22 VikasBansal Ex. -> using EMROI with Electrons, Header
Unknown file formatcxx EmRoiContainer.cxx r1 manage 4.5 K 2006-07-19 - 08:16 VikasBansal Filling EMROI Container
Header fileh EmRoiContainer.h r1 manage 1.5 K 2006-07-19 - 08:09 VikasBansal Specifying EMROI container
Unknown file formatcxx JetRoiContainer.cxx r1 manage 4.5 K 2006-07-19 - 08:18 VikasBansal Filling JETROI Container
Header fileh JetRoiContainer.h r1 manage 1.5 K 2006-07-19 - 08:10 VikasBansal Specifying JETROI container
Unknown file formatcxx MuRoiContainer.cxx r1 manage 4.5 K 2006-07-19 - 08:19 VikasBansal Filling MUROI Container
Header fileh MuRoiContainer.h r1 manage 1.5 K 2006-07-19 - 08:15 VikasBansal Specifying MUROI container
Compressed Zip archivetar ROIcodes.tar r1 manage 50.0 K 2006-07-19 - 08:34 VikasBansal Tar ball of above files
Texttxt r1 manage 2.7 K 2006-07-19 - 08:24 VikasBansal Athena JobO for using INav4Mom ROI
Header fileh UserINav4Mom.h r1 manage 1.3 K 2006-07-19 - 08:08 VikasBansal Class for deriving INav4Mom
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Topic revision: r4 - 2006-09-22 - VikasBansal
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