CMS Heavy Ion Software

NEW Dedicated twiki for 2018 heavy-ion reco developments: HiRecoTaskForce2018

This page is intended as the primary source of heavy ion specific software development and end user information. Development status and plans are discussed on the SoftwareTaskForce page. It is a supplement to the following resources:

Some hints on getting started with CMSSW and finding information are included at the end of this page.

CMSSW Release Plans

Table of heavy ion plans for future releases (beginning from CMSSW 33X)

CVS Subsystems and Packages reserved for Heavy Ions in CMSSW

CMSSW/SimDataFormats/HiGenData ( CVS, LXR ): Generated Data

  • This is the CVS area for data formats related to generated & simulated events (so far, this package contains: generated vertex & sub-event information)

CMSSW/DataFormats/HeavyIonEvent ( CVS, LXR ): For Reconstructed Data

  • This package is for all kinds of data formats that are common for both generated and reconstructed data. This includes:
    • Centrality : Various detector deposits and assigned centrality bin
    • Event Plane : Various event plane angle values corresponding to different measures

CMSSW/RecoHI ( CVS, LXR ) : Reconstruction Modules

CMSSW/CondFormats/HIObjects ( CVS, LXR ) : For Conditions Database Objects

  • Package to hold conditions objects that are related to Heavy Ions.

CMSSW/CondCore/HIPlugins ( CVS, LXR ) : To register conditions objects

CMSSW/HeavyIonsAnalysis/Configuration ( CVS, LXR ): For Physics Analysis

  • For high level heavy ion analysis code, EDAnalyzers and configurations
  • Currently keeping analysis code in UserCode e.g. UserCode/CmsHi/JetAnalysis



  • The PYQUEN event generator is integrated into CMSSW. Main contacts: Yetkin Yilmaz / Camelia Mironov / Igor Lokhtin.
  • Interface info available here


  • The HYDJET event generator is integrated into CMSSW. Main contacts: Yetkin Yilmaz / Camelia Mironov / Igor Lokhtin.
  • Interface info available here


  • Interface info available here


  • Interface info available here

J/Ψ, ϒ and Z generation

  • Generation can follow a flat particle gun or a distribution file of our choice (like Ramona Vogt's distribution for example). Details can be found here

Generator Common Tools

  • Tools for heavy ion event generation which are not specific to an individual Monte Carlo generator, e.g. HiCentralityBiasFilter, GenEvtSelectors. Details can be found here


Full Simulation

HI Event Mixing

HI Data Mixer

HI Event Tuning (under development)


  • The fast simulation could be an useful tool as it runs ~1000 faster than full simulation, but so far has not been used for heavy ions.



Reconstruction Software

Listed below are the various heavy ion reconstruction projects with the names of the main contact persons and links to the relevant web pages:

  • HI Muon Reconstruction -- Olga Kodolova, Camelia Mironov -- (main page)

  • HI Photon Reconstruction -- Yenjie Lee, Yongsun Kim -- (main page)

  • Pixel Tracklet Reconstruction -- Yenjie Lee -- (main page External site)

  • HI Event Plane Determination -- Sergey Petrushanko -- (main page)

  • HI Flattened Event Plane -- Victoria Zhukova -- (main page)

IDEA! An example of a full reconstruction configuration can be found in /UserCode/CmsHi/Utilities/test/ External site. Such configurations can be generated with cmsDriver with a script like

Zero Suppression

Trigger Software

  • Instructions for setting up the Heavy Ions HLT Menu can be found at this page
  • Instructions for setting up the Heavy Ions L1 Menu can be found at this page

Analysis Software

Some Heavy Ion analysis projects are listed below with contact people and relevant web pages:

A whole host of useful analysis tools can be found on the SWGuidePhysicsTools page.

Code for some individual analyses has also been documented and can be found at the following pages

  • DiMuon Trigger Analysis -- Ji Hyun Kim and Dong Ho Moon -- (main page)
  • Upsilon->Dileptons in Ultraperipheral collisions -- Vineet Kumar and David d'Enterria -- (main page)

Getting started with CMSSW

A reminder or maybe new information for people that are just getting started with CMSSW on sources of information to find (back) documentation:

1) The CMS Offline WorkBook

A very complete introduction to CMSSW and computing in CMS. Explains how many things work in the generation, simulation, digitisation and reconstruction. Also contains many pointers.

2) The CMS Offline Guide

Not quite as complete in all areas, but explains a lot about the EDM (Event Data Model) and the Framework that form the basis of CMSSW.

3) The LXR Cross Referencer

The fastest (only) way to quickly find your away around the CMSSW source code and config files. It allows the lookup of identifiers and random text for any version of CMSSW. It is also great to just browse and read.

4) Google

A very efficient way to find info about CMS/CMSSW add "" to find things in the CMS twiki. For example, search for


returns a top three of highly relevant pages documenting mixing/pileup in CMSSW (try for yourself!)

5) Example and Standard configuration samples

The CMSSW repository contains default and example configuration files you can use and derive from. In particular see:

Remote Computing Info

Assorted Tips and Links



Review Status

Editor/Reviewer and date Comments
EdWenger - 26 Oct 2009 Removed obsolete information
PhilipAllfrey - 17 Aug 2009 Copied content from CmsHiSoftware as part of documentation review
DavidDEnterria - 04 Jun 2007 Page Author

Responsible: EdWenger

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Topic revision: r38 - 2023-03-03 - SayanChatterjee

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