Physics Reconstruction Documentation

Overview

The physics reconstruction is implemented in the HPS Java project, which uses org.lcsim extensively for basic utilities like event processing, detector description and conditions interfaces.

A set of lcsim Drivers is used to process the raw data and produce collections of Tracks, Clusters, and ReconstructedParticles. The driver list is defined in an lcsim xml steering file read in by the lcsim job manager. The drivers created by the manager are processed using the LCSimLoop, which is a sequential recording processing loop.

The job manager can read in lists of LCIO files as defined in the XML steering format or from command line options. Post-processing or analysis of the recon can be done by reading in the LCIO files and supplying a steering file which implements the user's algorithm.

Quick Steps

EVIO data files are converted to LCIO events using the EvioToLcio command line utility.
The HPS Java reconstruction is run to produce physics object collections.
The recon LCIO is converted to ROOT DST Data Format so that the events can be easily analyzed in ROOT.
DQM files containing plots in ROOT or AIDA format may also be produced from analyzing the reconstruction output.

Package Documentation

The HPS Java Documentation can be used to browse the packages and classes used for physics reconstruction.

The following packages are related to physics reconstruction in HPS Java.

HPS Java Reconstruction Packages

Java Package	Description	Notes	Module
org.hps.evio	converts EVIO raw data to LCIO	evio readers for converting EVIO raw data to LCIO events	evio
org.hps.recon.ecal	ECal reconstruction utilities	primarily for converting from raw data to CalorimeterHits	ecal-recon
org.hps.recon.ecal.cluster	ECal hit clustering framework	includes recon clustering and GTP/CTP hardware emulation clusterers	ecal-recon
org.hps.recon.tracking	track reconstruction from SVT hits	based on Seed Tracker from lcsim	tracking
org.hps.recon.tracking.gbl	GBLtrack refit	ported from C++ to Java	tracking
org.hps.recon.particle	builds ReconstructedParticles from tracks and clusters	builds reconstructed particles from input event collections	recon
org.hps.recon.vertexing	vertex reconstruction	based on Billoir vertexing algorithm	recon
org.hps.recon.filtering	event skimming utilities		recon
org.hps.record.*	various data utils (DAQ config, SVT, trigger bank, etc.)		record-util
org.hps.analysis.dataquality	Data Quality Monitoring plots	runs on reconstruction output to produce DQM plots	analysis

LCSim Packages

These lcsim packages are used extensively in the HPS Java reconstruction code.

Java Package	Description	Notes
org.lcsim.event	physics event interfaces (implemented by LCIO)	interfaces used extensively in HPS Java Drivers
org.lcsim.util.loop	event processing facilities	extends Freehep loop classes for lcsim usage
org.lcsim.job	lcsim job manager which reads lcsim xml steering files
org.lcsim.lcio	Java implementation of LCIO file format	implements event interfaces
org.lcsim.recon.tracking.seedtracker	Seed Tracker track reconstruction algorithm	basis for HPS Java tracking
org.lcsim.util	Driver class for event data processing

External Packages

EVIO Data Conversion

The EvioToLcio utility converts EVIO to LCIO using an LCSimEventBuilder implementation such as LCSimEngRunEventBuilder. The generated LCIO events can then be optionally written to disk using an LCIODriver. The physics reconstruction may also be run in the same process.

SVT data banks are handled by an SvtEvioReader and converted into RawTrackerHit collections.

Various modes of EVIO TDC data from the ECal are converted using the EcalEvioReader.

The following collections are added to the event by the ECal reader.

EcalReadoutHits
FADCGenericHits
EcalReadoutExtraDataRelations
EcalReadoutExtraData

This builder will also convert and write DAQ config information, EPICS control data, and scalar bank data into the output LCSim events, if these banks are present in the EVIO data.

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