Using JAS3 to analyze LCIO files

There instructions explain how to use JAS3 to analyze LCIO files. LCIO files are a common file format for international linear collider physics studies. For more information about LCIO files visit the LCIO home page.

Installing JAS3 and the LCIO plugin

These instructions assume you have already installed JAS3 (version 0.7.3 or later) and the LCIOPlugin (version 0.8 or later).

Opening LCIO files

To open LCIO files use the File, Open File menu item. The files must have an extension of .slcio. The files must have been written using LCIO version 0.8 or later. One a file is open in will appear in the JAS tree under the "DataSets" node.

Any number of LCIO files may be opened simultaneously, but only one at a time can be the "Current Record Source". This is the file which is controlled via the run control toolbar.

The buttons on the toolbar can be used to switch the current record source, step through one event at a time, analyze all events, or rewind to the first event. You can also perform the same operations using the Run menu.

Using the Event Browser

To turn on the LCIO event browser use the LCIO, Event Browser menu item. The event browser shows the current event as selected by the run control toolbar.

Click on the different components of the event (in the Event tree) to view different tabulations of the data.

Using the MC Particle Tree

The MC Particle tree works similarly to the event browser, except that it shows the MC Particle hierarchy within the event. You can turn it on (or off) using the LCIO, MC Particle Tree menu item.

Analyzing Data

The easiest way to start writing an event analyzer is to use the LCIO, New Event Analyzer menu item. This will bring up a simple dialog:

Choosing the default options will create a complete sample analysis routine. To run it use the following steps:

  1. Save the file using File, Save. The filename must correspond to the name of the class (e.g.
  2. Compile the file, by right clicking on the editor window and choosing Compile from the popup menu.
  3. Load the program, by right clicking on the editor window and choosing Load.
  4. Run some data through the analyzer, by opening an LCIO file, and choosing Go from the Run menu.
  5. View your histograms or n-tuples by selecting them from JAS Tree.


Many more features coming soon...

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