LCD Analysis with JAS and ROOT

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Outline

• News from Simulation Workshop III_at_ ANL
• Detector Simulation
• Hit Digitization
• Event Reconstruction
• Event Analysis
• LCIO
• JAS3 Visualization
• org.lcsim reconstruction code
• Necessary RD and next steps.

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Simulation Workshop III _at_ ANL

• Four days (June 2-5) of talks, meetings and
  tutorials.
• two dozen participants.
• Several projects/ideas spawned then were reported
  on at this workshop.
• http//www.hep.anl.gov/lcsw/
• Another fruitful meeting, group is slowly
  achieving critical mass.
• Will be discussing when and where to hold SimIV
  soon.

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Greetings from Simulation Workshop III !
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Detector Simulation

• Geant4 now default production engine.
• Strong support from SLAC Geant4 team.
• xml file format used for Geant4 input. For
  flexibility and ease of construction, using
  simplified geometries, e.g. cylindrical barrels
  and disks.
• Maintain some standard geometries, others
  easily generated by users or upon request.
• lcdg4 (NICADD) writes sio files.
• lcs (SLAC) writes lcio files.

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Updated Geometries

• Can define n-sided detectors.
• user-defined slicing of stave modules
• Developing new xml schema for geometries.

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Slicing

• Arbitrary slicing of subdetector staves.
• e.g. SiD Si/W EMcal.
• Could also use for hybrid Si/Sci.

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Hit Digitization

• Calorimeter information quantized at Geant4
  stage. Digitization package being designed.
• Tracker information requires post-processing.
• Enables studies of detector strip, pixel sizes,
  charge sharing, electronic noise, etc.
• Provides more realistic simulation of effects of
  backgrounds and noise
• Nearby hits merged
• Hit-specific measurement uncertainties.
• Ghosts.

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CCD Digitization (N. Sinev)

• VXD hits from simulated events, finds charge
  deposited in each pixel, adds electronics noise
  and digitizes signal.
• Finds CCD clusters, splitting if necessary.
• Coordinates of found centers are used to replace
  tracker hits in the simulated events. Further
  event processing (track finding, fitting, and so
  on) proceeds the same way as it was before.
• Can set CCD parameters (like thickness, depleted
  layer depth, epitaxial layer thickness and so
  on), electronics parameters (noise, ADC
  conversion scale, pixel and cluster thresholds),
  processing parameters (like cluster center
  calculation method).
• hep.lcd.mc.CcdSim

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TPC Digitization D. Peterson
Create hits, with time and pulse height,
centered on the average position in the cell
Wave Form to simulate time ( Z) response
Gaussian charge spreading on the pads
Threshold crossings found in this procedure
replace the original pad signals.
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Si ?strip

• Digitization package reported on at ALCPG04 in
  January.
• Several efforts devoted to tiling studies of
  subdetectors (see tracking session summary).
• Allows occupancies to be studied as functions of
  strip lengths, orientation, charge sharing, and
  ghosting due to stereo strip associations.

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Tiling Forward Disks
Wedges
Hexagons
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Event Reconstruction Tracking

• Quite a bit of effort being devoted to developing
  and improving track finding
• Forward Tracking code implemented.
• VXD standalone tracking developed (N. Sinev)
• works even in presence of full backgrounds!
• Barrel track finding for SiD being developed
• inside-out (S. Wagner)
• outside-in (E. von Toerne, D. Onoprienko)
• TPC tracking being worked on (D. Peterson)

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Event Analysis

• Aim is to demonstrate full Particle Flow
  reconstruction.
• ReconstructedParticle concept and example
  implementation introduced at Cornell.
• Several groups now working on various aspects
• Quite a few talks at this workshop.
• Finishing up ?-finding high priority.
• Refine track-cluster association.
• Forward tracking code released.
• Muon-finding software being actively worked on.

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Calorimeter Tracking Clustering

• Muons (including MIP tracking in cal)
• C. Milstene
• EM MIP stubs
• W. Mader
• Photons
• G. Wilson, U. Nauenberg et al.
• K0S Finder
• E. von Toerne, D. Onoprienko
• digital vs hadronic HCal clustering analyses
• NICADD, UTA, ANL

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Calorimeter Assisted Tracking K0S
(GeV)
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Shower reconstruction by track extrapolation
ECAL
HCAL
Mip reconstruction Extrapolate track through
CAL layer-by-layer Search for Interaction
Layer - Clean region for photons
(ECAL) Shower reconstruction Define tubes
for shower in ECAL, HCAL after IL Optimize,
iterating tubes in E,HCAL separately (E/p test)
IL
track
shower
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Total Energy Sum Tracks Photons Neutrals
G4v6.1

• 2 Gaussian fit
• mean 83 GeV
• ? 7.8 GeV
• Poor hadron shower reconstruction with tubes
  more sophisticated approach
• mean 87 GeV
• 4.7 GeV
• Good hadron shower reconstruction

After tuning, very similar results
Z?hadrons _at_91GeV cms
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Particle Flow

• Development has been quite rapid in last 6
  months.
• Many of the pieces are close to being released.
• Plugin architecture of reconstruction has allowed
  groups to island hop around missing
  functionality.
• use MC info until missing package is supplied.

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LCIO
Java, C, Fortran
Java, C, Fortran Geant3, Geant4
Java, C, Fortran
geometry
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LCIO Producers Clients

• LCIO simulated detector response
• European Mokka package.
• American lcs package.
• Interest expressed by Asian simulation group.
• lelaps
• TPC hardware groups actively using.
• Cal TB groups using/planning to use.
• JAS3 and org.lcsim analysis packages.
• European Brahms reconstruction.

G4
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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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WIRED3 with LCIO Plugin
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LCIOPlugin with WIRED4
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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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International Cooperation I

• ACFA simulation group intends to add lcio output
  to Jupiter.
• Have nice description of BDS elements.
• Obvious benefits in working together on this!

Looking forward to ACFA workshop in Taipei. Hope
to be able to actively participate, perhaps
arrange simulation mini-workshop.
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International Cooperation II

• Active collaboration with European colleagues in
  development of LCIO and new event data model.
• Brahms continues to be main reconstruction
  package and framework for reconstruction.
• LCIO compliant, but strong desire to move away
  from FORTRAN to newer OO environment.
• Variety of Particle Flow algorithms being
  developed by several groups, but no coherent
  program to date.

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Necessary RD

• Many of the tools necessary for characterizing
  detector designs exist
• fast and flexible detector response simulation
• signal background samples and merging code
• detector digitization, hit merging close
• track and calorimeter cluster reconstruction
• various parts of Particle Flow reconstruction
  exist
• Need more people to use and develop!

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Summary

• Significant progress during the last 7 months.
• GEANT4 established as default
• LCIO reco event model done being adopted by
  more groups.
• Much progress in tracker detector digitization.
• Track finding strategies being actively
  developed.
• The developer/user community is growing there
  is progress in developing reconstruction
  algorithms, especially Particle Flow.

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Summary -

• Most of the reconstruction progress uses older
  hep.lcd software sio input.
• Need to transition to org.lcsim and lcio!
• Moving to lcio and org.lcsim promises payoff in
  terms of more functionality international
  collaboration, but requires upfront investment in
  transitioning code.
• Still need more people to USE the code to
  undertake physics and detector studies.
• We have not yet begun to analyze!

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Feedback

• Need feedback from physics and detector groups on
  their requirements.
• What detector capabilities do we need to
  benchmark?
• What changes are needed for the canonical
  detector(s)?
• What do we need to deliver (and when) for you to
  accomplish your goals for LCWS?

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to Reality
From Hits
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Whats the reality here?
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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