hepmcvisual is hosted by Hepforge, IPPP Durham


This project consists of two subprojects, that are partially interlinked:

  • HepMCVisual: a library for interactive inspection of HepMC records
  • HepMCBrowser: an Athena algorithm with a GUI to view events from ATLAS pool files

Although this project has been around for a while, not all of this has been widely tested yet — please contact the author if you run in any trouble.


  • Fortunately, this project will be continued by Moritz Bunse.
  • HepMCBrowser has been presented at CHEP09 - there is a poster and a paper.
  • Since release 15.0.0 HepMCBrowser is part of Athena.
  • There is now a demonstration video available for HepMCBrowser here.
The latest version can be obtained from the download section. Installation instructions can be found in the INSTALL files in the top directory of the respective package.


HepMCVisual is a library providing visual and interactive counterparts to the three base classes provided by HepMC:
  • HepMC::VisualParticle : a particle represented by a line, can be clicked on to get name, momentum, etc...
  • HepMC::VisualVertex : a vertex represented by a dot, with in- and outgoing particles. Vertices can be moved around in order to make a clear image.
  • HepMC::VisualEvent : a collection of vertices which own a list of particles. The event itself has no graphical representation.
All of these classes are directly inherited from their HepMC::Gen[Particle|Vertex|Event] counterparts and use ROOT graphic libraries, i.e. can be drawn on any ROOT Canvas using Draw(). Simple functions are provided to convert the HepMC::Gen* classes into their visual representations.
  • HepMC::Visualize(Gen[Particle|Vertex|Event]*) : convert the HepMC objects to their visual counterpart
The conversion can be started in any element of the event graph, and will be automatically continued while the user explores the event.
The Event-Tab of the HepMCBrowser
    GUI window


The Event-Tab of the HepMCBrowser
    GUI window HepMCBrowser is a python algorithm that can be run in an interactive Athena (the ATLAS analysis framework) season. It provides a GUI interface, that lets you search for a specific event in the EventCollection, search for specific vertex in that event and then displays it using the HepMCVisual libraries.

Currently linking to the particle data tables is not supported - I am working on this. Meanwhile, all the particles are identified by their PDG Id's.

The current version of HepMCBrowser is shipped with any release after Athena 15.0.0. Older version are also working with a release for Athena 13.0.40, but am not planning to support 12.0.6 at the moment.

If all of this sounds gibberish to you, you might want have a look at the ATLAS Computing Workbook.