Linear Collider Simulation Tools Norman Graf ECFA LC Workshop Durham, Sep. 4, 2004

Detector Requirements Detectors designed to exploit the physics discovery potential of e+e- collisions at s ~ 1TeV. Will perform precision measurements of complex final states. Require: Exceptional momentum resolution Excellent vertexing capabilities “Energy Flow” calorimetry Hermeticity 11/28/2018 Norman Graf

Detector Requirements Yes, but still need to quantify! Exceptional momentum resolution is dp/p ~ few 10-5 really necessary! How important is material? Excellent vertexing capabilities What are the effects of inner radius, thickness, number of layers “Energy Flow” calorimetry Is 30%/E needed? Can we do better? 11/28/2018 Norman Graf

Particle Flow Motivation Measure momenta of charged tracks in the tracker with superb resolution. Measure photons in highly segmented EM calorimeter with reasonable resolution. Remaining neutral hadrons measured in hadron calorimeter. 11/28/2018 Norman Graf

No tool is too simple… 11/28/2018 Norman Graf

Tracker Resolution Tool lcdtrk Bruce Schumm has developed a nice tool which allows rapid investigation of tracker designs. Input is simplified geometry, materials and point resolution. Output is resolution plots plus covariance matrices which can immediately be used to smear tracks in the fast Monte Carlo. http://www.slac.stanford.edu/~schumm/lcdtrk.tar.gz 11/28/2018 Norman Graf

Fast MC Covariantly smears charged tracks. Smears neutral calorimeter showers by expected resolutions. Can be used as input for further analyses. Jet Finding ZVTop vertexing Can vary resolutions at analysis time and produce plots of x vs resolution, eff., etc. 11/28/2018 Norman Graf

LC Detector Full Simulation MC Event G4Application Raw Event Geometry Geometry Database GEANT4 Reconstruction, Visualization, … 11/28/2018 Norman Graf

LCD Full Simulation Geometry defined in XML. Flexible, but simplified volumes. Projective readout of sensitive volumes. Dynamic topology, not just parameters. Have defined generic hit classes for sensitive tracker and calorimeter hits. LCIO bindings for I/O. 11/28/2018 Norman Graf

LC Detector Simulations Use simplified volumes to investigate larger number of designs, allowing dynamic topologies using single executable. Describe “optimal” detector in detail. TPC Tracker, Si Disks, CCD VTX 11/28/2018 Norman Graf All Si Tracker, CCD VTX

Reconstruction/Analysis Overview Java based reconstruction and analysis package Runs standalone or inside Java Analysis Studio (JAS) Fast MC Smeared tracks and calorimetry clusters Full Reconstruction track finding and fitting calorimeter clustering Individual Particle reconstruction (cluster-track association) Analysis Tools (including WIRED event display) Physics Tools (Vertex Finding, Jet Finding, Flavor Tagging) Beam Background Overlays 11/28/2018 Norman Graf

hep.lcd 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 SLD’s 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, … 11/28/2018 Norman Graf

hep.lcd analysis tools Tutorial: http://jas.freehep.org/jas3/Tutorial/index.html 11/28/2018 Norman Graf

WIRED3 Event Display Tree controls visibility. (HepRep2 support in WIRED3 is preliminary) Picking supports viewing physics attributes 11/28/2018 Norman Graf

Reconstruction Status Full Reconstruction package which incorporates all aspects of the Particle Flow paradigm, works for any detector, and works out-of-the box is not currently available. However, many of the pieces are in place, can be used today, & active work is underway to incorporate into a finished product. See talks in simulation session. 11/28/2018 Norman Graf

Testing Samples Testing reconstruction on simple events. Study finding efficiency, fake rates and measurement resolutions (E, p, mass) using: Single Fundamental Particles e+/-, , +/-, +/- Simple Composite Single Particles 0, , , ,  Complex Composite Single particles Z, W Physics Events 11/28/2018 Norman Graf

Conclusions A fairly complete suite of simulation tools exists for LC physics and detector studies. Contributions to the full reconstruction welcomed and invited, but much can be done within the existing framework with released software. 11/28/2018 Norman Graf

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Most important tool of all! 11/28/2018 Norman Graf

Links LC Simulations: http://lcsim.org JAS3: http://jas.freehep.org/jas3 WIRED: http://wired.freehep.org/ Discussion Forums: http://forum.linearcollider.org 11/28/2018 Norman Graf