r37 - 21 May 2008 - 17:26:33 - RobertHarringtonYou are here: TWiki >  AtlasSoftware Web > MuonAnalysisSupport


Muon Analysis Support


A great place to start with muon software is Dan Levin's MuonRecoPedia . There is quite a large amount of information there to digest. The performance wiki can be found at Combined Muon Performance group which was developed to consolidate and evaluate the muon software.

Muon Spectrometer Overview

A detailed description of the Muon Spectrometer can be found in the Muon Spectrometer TDR Homepage. Here we give only a breif overview of the spectrometers most salient features. The spectrometer has been designed to optimize the physics potential in both Standard Model benchmark process (W and Z production and subsequent decays, beauty physics and CP Violation) and searches for both the Stadard Model and supersymmetric Higgs as well as new heavy vector bosons. A subset of the important parameters considered were:

* Resolution: Mass and Momentum resolution at the level of 1% for intermediate Higgs masses (140-200 GeV) and 10% resolution of the transverse momentum resolution of 1 TeV muons * Second-Coordinate Measurement: A position measurement in the non-bending projection with a resolution of 5-10 mm: * Rapidity Coverage: Eta coverage up to 2.7 * Trigger Selectivity: The capability of triggering on 'high Pt' muons with Pt > 20 GeV and lower thresholds, 5 GeV, required for b-physics * Bunch-Crossing Identification: The ability to resolve the proper bunch-crossing given the LHC bunch-crossing interval of 25 ns * Background Conditions: Coping with the high level of particle fluxes from the intense radiation environment at the LHC.

In order to achive these goals a sophisticated spectrometer has been designed comprised of three torioid magnets (one barrel and two endcap toroids) with several planes of detectors to identify and measure the momenta of the incident muons.

Annotated figures

An annotated description of the detector can be found in the file, MuonSpectrometer_Nomenclature.ppt . V2 is the latest effort.

The file MuonSpectrometer_NumHits.ppt has a tabulation of the number of hits expected for the precision and phi coordinates.

Muon Reconstruction

The starting point for all ATLAS muon software is the Muon Software Wiki. Here you will find information regarding the various reconstruction programs. To learn how to run these programs you can visit the Muon Reconstruction Wiki. Which has a series of how to hands on approaches. To take a look at the muon reconstruction performance visit the interactive performance wiki.

Muon Trigger

A good place to start is the ATLAS trigger wiki which can be found at: ATLAS DAQ and Trigger Wiki

From there you will also find the Muon PESA webpage which will give you (unfortunately not always up to date) recipe on how to run the trigger simulation.

Muon AOD Analysis

There are currently two muon containers: Staco and Muid. AodKeys will show you the names of the containers and what type of objects there are. There are several tutorials which can help you understand how to access the data from the AOD with Athena. Probably the most complete is Ketevi's tutorial which will step through from login to producing plots.

Monte Carlo Samples

There are several useful data samples stored at the Tier 1 at BNL. There are two tools to find these data samples:

Finding Datasets with Panda Tools

A very powerful and user friendly tool is the panda data browser. For example the muon data at bnl can be accessed quite easily. In principle one should be able to get access to any of the datasets registered as a part of the ATLAS grid project. Unfortunately, we have a finite amount of money and hence a finite amount of resources so its best not to copy huge datasets to your own area (imagine if everyone in atlas had there own personal copy of all atlas data). For running over large data samples it is best to get acquainted with panda tools. You can find a good example of Data Analysis with Panda which is kept up to date by Tadashi. The pathena tool is remarkably user friendly for all the complexity it is hiding. As you will see there is not too much more to doing analysis with this tool other than the one extra character stroke - which is considerably less work than the batch job submission.

For example you can find the location of single muon events

Single Muons

Finding Datasets with AMI Dataset Selection

You can also find data using AMI Datasets Selection. You can search on the dataset name. Single muons have dataset names with singlepart_mu followed by the Pt cut. If you want single muon events with 10 GeV, you can search for datasets with "singlepart_mu10.".

Smaller data samples

Of course for development of your code its useful to have a small data sample that you can run over very quickly to iterate with. Here are a few simple events for fast access and development.

pre-12.0.4 Zmumu from Stephane /usatlas/u/willocq/scratch0/12.0.4n/batch_Zmumu/rel_6/aodfiles
12.0.4 Zmumu from Stephane /usatlas/u/willocq/scratch0/12.0.4/Zmumu/aodfiles_allalgs
12.0.3 dijet samples /pnfs/usatlas.bnl.gov/u04/paige/jXsamp where X=1,2,...,8

the general area at cern where this data is kept is on castor at:

Samples with cavern background and pileup:
For Nominal geometry ATLAS-CSC-01-00-00 and Released used 12.0.4


for fixed pt= 5, 10, 50, 100, 300 GeV -2.7 < η < 2.7 and -π < φ < π (each file contains 100 events) (for the moment pt at 5,100 GeV are available)

The location of the cavern(for all safety factors) and minbias files recently produced for both geometries is under:


similar for other sf's

For the minbias:

Cosmic Ray Data

For information on the sector 13 cosmic data see the Sector 13 Data Taking

Ed Diehl has copied over some sector 13 cosmic ray data. You can find it at bnl at:

To analyze follow the instructions shown: Cosmic Ray Data Reconstruction. This will walk you through the various steps needed to get running.

Test Stand Data

There is also some test stand data that is available for special analysis. This is really only intended to be digested by experts
This data is not in the standard form readable by Athena. It is also not the standard raw data that would come from the daq system since it has been readout with a standalone system. There are also known problems with the data format. If you really want to look at this data it will require some work on your own to understand how to interpret the files. Please contact kblack_AT_fas.harvard.edu for more information.

Data taken from the pit with the test stand setup can be found on the tier 2 at BU at:

Data taken at building 180 can be found at

Ongoing US ATLAS Muon Activities

This is a partial list only. If you are missing, please contact us or add yourself to the list!


  MDT alignment     Brandeis University    James Bensinger 
  MDT commissioning    University of Michigan    Dan Levin 
  MDT calibration     University of Michigan    Edward Diehl 
  MDT alignment with tracks     Boston University    Robert Harrington 

Muon Reconstruction and Identification:

  muon reconstruction validation studies     Brookhaven National Laboratory    David Adams 
  detector effects on muon measurements     University of Michigan    Steven Goldfarb 
  calibrating and validating muon isolation strategies     UC Irvine    Daniel Whiteson 
  muon real and fake identification     University of South Carolina    Milind Purohit 

Preparations for Early Physics:

  top quark physics with muon + jets     Oklahoma State University    Muhammad Saleem 



Major updates:
-- TWikiAdminGroup - 11 Jul 2020

About This Site

Please note that this site is a content mirror of the BNL US ATLAS TWiki. To edit the content of this page, click the Edit this page button at the top of the page and log in with your US ATLAS computing account name and password.


ppt MuonSpectrometer_nomenclature.ppt (1147.0K) | KevinBlack, 16 Jan 2007 - 11:29 |
ppt MuonSpectrometer_NumHits.ppt (346.5K) | KevinBlack, 16 Jan 2007 - 11:28 |
ppt MuonSpectrometer_nomenclature_Version2.ppt (1193.0K) | KevinBlack, 16 Jan 2007 - 11:29 |
jpg Atlas_Medal_t.jpg (18.3K) | KevinBlack, 09 Jan 2007 - 14:54 |
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