Reconstruction and Analysis Tools for LC physics

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Reconstruction and Analysis Tools for LC physics

• Tony Johnson
• SLAC
• Victoria Linear Collider Workshop
• July 2004

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Contents

• Existing Code
• Review capabilities of existing hep.lcd package
• LCIO Overview and Status
• LCIO Reconstruction Output
• LCIO Analysis package for Java/JAS3
• WIRED Event Display
• Recent developments (work-in-progress)
• Port of entire reconstruction/analysis framework
  to LCIO/Java 1.4(5)/JAS3
• Issues
• Timescale
• Future Plans
• International Reconstruction/Analysis Framework

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hep.lcd Reconstruction and Analysis Package
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hep.lcd Overview

• Java based analysis reconstruction and analysis
  package
• Runs standalone or inside JAS
• Full Reconstruction (trackingcalorimetry)
• Analysis Tools (including WIRED event display)
• Fast MC
• Smeared tracks and calorimetry clusters
• Physics Tools (Vertex Finding, Jet Finding)
• Beam Background Overlays
• Contributed Area
• Analysis Utilities and sample analyses provided
  by users

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hep.lcd Physics Utilities

• Physics Utilities
• 4-vector, 3-vector classes
• Event shape/Thrust finder
• Jet Finders
• Many kT algorithms implemented (e.g. Jade and
  Durham )
• Extensible to allow implementation of other
  algorithms
• Event Display
• Topological Vertexing
• Implementation of SLDs ZVTOP
• Event Generators
• Can be run directly in FastMC
• Can be run standalone, e.g. for writing stdhep
  files
• Diagnostic Generator
• User-defined particle mix, momenta and vertices.
• Generator framework extensible for other
  generators
• PYTHIA, HERWIG, ISAJET,

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Full Reconstruction

• Reconstruction of fully simulated MC data.
• Designed to allow easy implementation of
  different algorithms.
• Reconstructs low-level objects tracks and
  calorimeter clusters.
• Further reconstruction (jets, flavor-tagging,)
  deferred to analysis stage.

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Full Reconstruction

• Tracking
• Hit Smearing/Efficiency (detector simulation puts
  out perfect hits)
• Random Background overlay
• Track Finding
• Full pattern recognition in the Central Barrel
  region
• Tuned for Large and Silicon Detectors
• Track Fitters
• SLD Weight Matrix Fitter
• Can do Single Detector or Combined fit (e.g.
  VTXTPC)
• Calorimetry
• Cluster Finding
• Several Clustering Algorithms Currently
  Implemented
• Cluster QA package developed
• Cluster Refinements
• Combine HAD EM clusters
• Endcap Barrel overlap region
• Identify cluster as originating from
  charged/neutral hadron, EM

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Beam Background Overlays

• Take output from full beam simulation (from
  IR/backgrounds group)
• Feed into full detector simulation
• Build library of simulated background bunches
• Overlay backgrounds on signal events at start of
  reconstruction
• Adjust timing of hits (for TPC e.g.)
• Add energy in calorimeter cells
• Allows to change bunches/train, bunch timing

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Recent improvements to hep.lcd

• Ported to work with JAS3
• Old packages running in JAS3/AIDA framework
• No major changes to reconstruction framework
• New digitization routines being added (N.Sinev)
• Cluster identification code (G. Bower)
• Cluster diagnostic package (R. Cassell)
• Improved Stepper (C. Milstene)
• Forward Tracking (N. Graf)
• Flavour Tagging (D. Jackson)
• Particle ID (B. Wilson, S. Rolnick)
• Support for Non-Projective geometries (G. Lima)

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hep.lcd analysis tools

• Tutorial http//jas.freehep.org/jas3/Tutorial/ind
  ex.html

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hep.lcd package pros-and-cons

• Features
• Can run standalone or inside JAS
• Runs on almost any platform
• No dependencies on pre-installed software or
  network connections. Can install and run in
  minutes from Snowmass 2001 CD
• Problems
• Few changes/improvements since Snowmass 2001
• IO based on old LCD SIO format
• No way to write output from reconstruction

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LCIO
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Introduction to LCIO

• International Standard for linear collider data
  storage

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Motivation for LCIO
Java, C, Fortran
Java, C, Fortran Geant3, Geant4
Java, C, Fortran
geometry
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Data Model I
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Data Model II
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Data Model III
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Data Model IV
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LCIO Status

• LCIO 1.0 release (simulation/rawdata) stable
  since November 2003
• LCIO 1.1 (beta reconstruction) may 2004
• LCIO 1.2 (stable reconstruction) august 2004
• micro workshop at SLAC mid-august to finalize
  design

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LCIO plugin for JAS3

• Works with any LCIO file
• Diagnostic tools allow to step through and view
  events

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LCIO plugin for JAS3

• Event Analysis

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Using WIRED with LCIOPlugin

• LCIO files do contain positions of all hits, but
  no detector geometry info except detector name
• LCIOPluginWIRED can view hits for any file, but
  these are hard to visualize without detector
• LCIOPlugin can read external HepRep2 file
  describing detector geometry
• Location currently needs to be specified by hand
• HepRep file (xml) can be generated
• by hand (quite easy for simple geometry)
• by Geant4 using HepRep2 writer (perhaps with some
  filtering to remove excess details)
• By program using Java or C HepRep API
• Easy to add analysis specific code to create
  visualizations for special items (jets, vertices
  etc.)

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WIRED3 with LCIO Plugin
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LCIOPlugin with WIRED4
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LCIO Plugins pros-and-cons

• Features
• Not dependent on any detector specific
  assumptions
• Simple environment for debugging problems with
  LCIO and writing simple analysis routines
• Detector independent event display
• Problems
• No connection to hep.lcd reconstruction or
  analysis tools
• Detector geometry must be specified by hand
• Existing LCIO API does not emphasize
  user-friendliness
• Detector geometry must be specified by hand

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Current Work org.lcsim package
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org.lcsim Goals

• Retain core functionality from hep.lcd package
• Full suite of reconstruction and analysis tools
  available to all LCIO users
• Update to use LCIO for IO and as basis for
  simulation, raw data and reconstruction event
  formats.
• Update/simplify framework using experience from
  hep.lcd
• Internationalization
• Try to make package independent of detector,
  geometry assumptions so can work with any
  detector
• Read properties of detectors at runtime
• Update to Java 1.4 (or 1.5)
• Many improvements since hep.lcd framework was
  created.
• Ability to run standalone or in JAS3
• Revitalize work on reconstruction algorithms

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org.lcsim Status

• Physics Utilities - done
• stdhep reader
• 3, 4-vector utilities
• diagnostic generator
• Jet finder, event shape utilities
• Org.lcsim package Phase I
• Conditions framework done
• Ability to read detector constants from zip
  file
• To define new detector just create new zip file
  and place on web
• File is read and cached locally
• Driver framework done
• Fast MC done
• IO Framework working, needs final LCIO 1.2
• Event Display interface in progress

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org.lcsim Status

• org.lcsim Phase 2 - Reconstruction
• Help needed!
• Geometry - J. McCormick, W. Langeveld
• Tracking M. Ronan, E. von Toerne (et al)
• Calorimetry R. Cassell,
• Particle ID B. Wilson, S. Rolnick
• Digitization N. Sinev,
• Vertex Finding - ?

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Future

• Distributed catalog for finding LCIO files
• Work towards International Reconstruction-Analysis
  Framework
• Taking best features of existing tools
• Support for mixed-language (Java, C, Fortran)
  modules
• Perhaps Java backplane driving modules in any
  language, using LCIO as transient event store,
  and with common geometry/constants access??

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Conclusions

• hep.lcd package is old but still works and is
  being used for current analysis
• LCIO 1.2 format very nearly complete
• New org.lcsim package in development
• Base package will be released soon after LCIO 1.2
• Then need to start work on porting/developing
  reconstruction code
• More volunteers needed
• Goal Generate sample of fully simulatedreconstru
  cted events for SiD, Large detectors by end of
  2004

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Links

• LCIO http//lcio.desy.de
• hep.lcd http//www-sldnt.slac.stanford.edu/jas/Do
  cumentation/lcd/
• Tutorials
• http//jas.freehep.org/jas3/Tutorial/index.html
• http//www-sldnt.slac.stanford.edu/snowmass/Welcom
  e.html
• JAS3 http//jas.freehep.org/jas3
• WIRED http//wired.freehep.org/
• HepRep http//heprep.freehep.org/
• Discussion Forums
• http//forum.linearcollider.org