The basic concept of the ReactionFilter Plugin is to use a defined physics reaction, usually described in a configuration file, to analyze the reconstructed data (REST files) event by event testing the hypothesis of the proposed reaction. It creates an output root file referred to as Physics Analysis Root Tree (PART) which in turn will be analyzed by other code like the DSelector.
The plugin applies basic PID selection criteria (time, mass, and dEdx) and by default a Kinematic Fitter to the reconstructed charged track and/or neutral showers of each event and applies the Kinematic Fitter based on the chosen reaction requirements.
While the analyzers will usually not need to run this plugin by themselves, since this is generally done by the responsible operator running an analysis launch with all requested reactions from all analyzers at once, it is useful for any analyzer to understand the concept of the ReactionFilter plugin and its functionality, also in view of the fact that the analyzer is responsible to provide the definition of the reaction to the operator of the analysis launch.
- An introduction to the ReactionFilter plugin can be found in this DocDB document (at presentation) and some information on the wiki in Analysis DReaction. Note that most of this documentation is 5 years old and no updates have been made since then.
- Examples of how such a configuration files may look like, examine the online submission form: Create a Reaction Config File
- The particle selection criteria can be changed in the configuration file.
- Selection criteria can be applied to the reaction considered in the configuration file.
- The Kinematic fit constraints can be changed in the configuration file or the kinematic fit can also not be used at all.
- Important: Generally an analysis reaction is submitted to the global analysis system administrator, by the above link, who will run the reaction over the specified data set for all submitted reactions in one go. So the user will be provided with the resulting PART files. These files will have the specified reaction in their file name.
- This step by the administrator is called an Analysis Launch and details can be found here: Analysis Launch and Monitoring
- The output data (PART) will be located on the cache disk system of the jlab computing system. An example of such a location is /cache/halld/RunPeriod-2018-01/analysis/ver19/. The data is discriminated by Run-Period and version the latter referring to the software version begin used.