Trigger analysis tutorial based on 12.0.6


This tutorial is an update of the tutorials given in 12.0.4 by Olya Igonkina, Attila Krasznahorkay, Valeria Perez-Reale, Monika Wielers and was extended by Ketevi Assamagan for the StructuredAthenaAwareNtuple part. It contains the various examples covered in the previous tutorial. Depending on the way you like to analyse your favourite physics events: directly from AODs, using EventView or using the StructuredAthenaAwareNtuple, various exercises are shown below for each of the catagories. So it's up to you to decide which exercises you want to do. If you're particularly interested in taus, you might follow the Tau trigger tutorial which is tailored to the tau community.

The tutorial is based an analysing AODs. The production of ESD and AOD's will be typically done by the production team. If you want to reconstruct few of your favourite events yourself, you can run the default RecExCommon jobOptions and follow the instruction in the Computing Workbook or here. Note, the trigger is switched on per default, so you don't have to do anything special. If you do it in 12.0.6 the trigger menu which is loaded per default is called CSC-06. To find out which triggers are present in the menu have a look here.

Basic set-up

To use the release you need to do the following. Create your working directory workarea, e.g. testarea/12.0.6 and then do the default set-up as explained in the WorkBook.
source ~/cmthome/setup.sh -tag=12.0.6,opt
Now go to testare/12.0.6 and do the following
mkdir  AtlasOffline-12.0.6
cd  AtlasOffline-12.0.6
To be sure your set-up is ok, check that your working area is included in the CMT path
Now you have the set-up as you are used to do and can check out the UserAnalysis package (unless you're only interested in the EventView examples.
cmt co -r UserAnalysis-00-09-10-01 PhysicsAnalysis/AnalysisCommon/UserAnalysis 
cd PhysicsAnalysis/AnalysisCommon/UserAnalysis/cmt
To include the Trigger you have to add one line to the requirements files in the cmt directory
use TrigSteeringEvent     TrigSteeringEvent-*       Trigger/TrigEvent
Now let's first compile the default
cmt config
source setup.sh
cd ../run
get_files AnalysisSkeleton_topOptions.py
ok, now we have set-up what we need for this tutorial. Note, next time you log in you you should re-issue the command source setup.sh in UserAnalysis/cmt.

Exercises for running directly on AOD's

Exercise 1a : Retrieve Trigger Decision

The TriggerDecision contains the Trigger Menu covering L1, L2 and EF. In this example you will learn how to retrieve the TriggerDecision from an AOD and how to find out if your events have been accepted or rejected by a given trigger menu item.

To go to the Exercise, click here.

Exercise 2a : re-run the hypothesis on AOD's

In this exercise we want to re-run the hypothesis algorithm(s). This very likely you will have to do this in release 12.0.6 to get a more correct trigger response. We'll first need to look at the reconstructed csc produced data ourselves and re-optimise the trigger selection cuts. So to allow you to use our latest optimisations, you might want to do something similar as inthis exercise (detailed recipes what to change will be provided in time).

To go to the Exercise, click here.

Exercise 3a : select events via trigger information in tags

In this exercise, we will use the TAG to select the final states of interest. In your analysis you might be interested in just the events in a given stream, e.g. the electron or jet one. Let's use out top events and select the ones which pass the e25i trigger. In the tags you find for each trigger menu item if the trigger passed or failed.

To go to the Exercise, click here.

Exercise 4a : creation of CBNTAA from AOD

If you wish to create a 'normal' Athena-Aware CBNT from AOD's and then analyse this one, you might want to try the following exercise.

To go to the Exercise, click here.

Exercise 5a : extract tau trigger EDMs

In this example we will have a closer look at the tau's. You will see how to retrieve the relevant tau EDM classes .

To see the excercise, do the set-up and Exercise 4 in Tau Trigger Tutorial

Exercises for running on AOD's using EventView

Preface: A short description about EventView

EventView is best known as an analysis framework in Athena, but it's foremost an analysis object container. (See the publicity picture below.)


There are three separate sub-containers in the object:

  • Final State Objects (FS): This is the place for the preselected truth/reco/trigger objects from the AOD. These form the basis of our view of the event.
  • Inferred Objects (IO): The framework allows you to reconstruct objects from final state particles (like W or top). This part is not covered in this tutorial.
  • User Data (UD): This is the place to put simple objects (numbers, vectors of numbers, etc.) to during the analysis. The main advantage is, that all the variables stored in the UD can be written out to an ntuple by the analysis job.

The EventView object is located in the PhysicsAnalysis/AnalysisCommon/EventView package. The "core" tools for performing an analysis in EventView can be found under PhysicsAnalysis/EventViewBuilder. The package holding tools specifically for manipulating trigger objects is: PhysicsAnalysis/EventViewBuilder/EventViewTrigger.

There is a very good documentation about EventView on the TWiki. Specifically, the tutorial TopViewTutorial covers many topics not mentioned here. You can also find some documentation about the EventViewTrigger package on the TWiki.

Exercise 1b : Retrieve Trigger Decision

This exercise will show you how to retrieve the TriggerDecision using EventView. An example will be shown for the electronand photon triggers.

To see the excercise, click here

Exercise 2b : Creating an ntuple with the dump of all trigger information

This might be the first thing someone would want to look at. The EventView tools support creating an AA ntuple with reconstructed, truth, and now even trigger information.

To see the excercise, go to EventViewTriggerTutorialEx1.

Exercise 3b : Associating trigger objects to truth and reconstructed objects

A very useful thing to do can be to find out if the trigger found a given truth or offline object, and also to have a look at it's properties. This tutorial shows how to associate tau trigger objects from the different levels to the true and reconstruced taus, and how to create a "structured" ntuple with the associated information.

To see the excercise, go to EventViewTriggerTutorialEx2.

Exercise 4b : Analyzing an EventView ntuple

Usually one doesn't do the whole analysis (at least not in the first step) in EventView. This excercise shows how to plot simple quantities from an EV ntuple, and also how to implement more serious macros that loop over the events one-by-one.

To see the excercise, go to EventViewTriggerTutorialEx3.

Exercises for running on the StructuredAthenaAwareNtuple

The StructuredAthenaAwareNtuple stands for Structured Athena-Aware NTuple. The StructuredAthenaAwareNtuple is an AthenaAwareNTuple where some or all the TBranches in the NTuple have structured Objects such such the AOD Electron object. The data structure in the NTuple is compact without any loss of information content. allowing easy browsability. For example, you do not have to search for one variable out of the several hundred as in the ordinary CBNT. StructuredAthenaAwareNtuple replicates the structure of the AOD in ROOT, allowing you to issue nearly the same commands in ROOT as you would do on the AOD in Athena. The StructuredAthenaAwareNtuple also allows to be able to share analysis codes developed in ROOT within or across groups; the StructuredAthenaAwareNtuple further provides the ability to port pieces of codes back into Athena. The StructuredAthenaAwareNtuple is being produced centrally together with the TAG in the central production. For details on getting started with the StructuredAthenaAwareNtuple, follow this link: StructuredAthenaAwareNtuple.

Exercise 1c: Retrieve the TriggerDecision from the StructuredAthenaAwareNtuple

As a first exercise you probably again want to retrieve the TriggerDecision and see how well your events are selected by the various triggers.

To see the exercise go the this section in this StructuredAthenaAwareNtuple section


This page has been set-up for people like you. So please leave here your feedback and help improving this tutorial for future users. Alternatively send an e-mail to one of the authors.

Major updates:
-- RicardoGoncalo - 03 Aug 2007

%RESPONSIBLE% RicardoGoncalo
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