Документ взят из кэша поисковой машины. Адрес оригинального документа : http://zebu.uoregon.edu/~uochep/talks/talks01/Root2001.pdf Дата изменения: Wed Sep 5 02:41:41 2001 Дата индексирования: Tue Oct 2 10:50:13 2012 Кодировка: Поисковые слова: ultraviolet

Root at the LCD
6/13/2001 M. Iwasaki Univ. of Oregon


North American Linear Collider Detector Group (LCD) has constructed a simulation facility based on Root Ю LCD Root

So far we only support Linux and SunOS (developing Windows)


Event generation at LCD Root
· PANDORA-PYTHIA (C++) by M.Peskin Ю our main generator include beam polarization, beamstrahlung CINT implementation directly use in C++ interpreter · PYTHIA (TPYTHIA: supported by ROOT) Output : ROOT or stdHEP (HEPEVT common) ROOT can go through FastMC stdHEP can go through FullMC (GISMO) & FastMC Or can be directly linked to FastMC


Detector Simulation at LCD Root
We use 2 kinds of detector simulations · Fast simulation For physics studies · Full simulation For detector studies Fast simulation Smear particle position/energy and IP position Output Root or is directly linked to Event Analysis Full simulation (GISMO) make digitized detector outputs (SIO binary) Full recon make tracks and clusters Output Root or is directly linked to Event Analysis


Detector Simulation at LCD Root
LCD Group considering 3 kinds of Detector designs Silicon, Large, and Precise Ю Different Detector sizes, materials, and Calorimeter Configurations.... Coil HAD HAD OR Coil EM EM ... We prepare 3 kinds of Detector geometry files Detector resolution files (for smearing) Some/all of these parameters can also be changed at user analysis level


Event Analysis at LCD Root
We have several useful analysis tools for Linear Collider experiments ·Jet Finder ... 3 kinds of algorithms ·Thrust Finder ·Particle extrapolator ·Topological Vertexing ... translated from SLD ZVTOP


Jet Finder
3 kinds of algorithms .. Jade, Jade E, and Durham Comparison of original Fortran Jet Finder and ours Fortran LCD Root (C++)
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(tt 6jets event) # of Jets

# of Jets

Works well!


Thrust Finder
tt events events

Works well!


Topological vertex finder Translated from SLD ZVTOP Reconstruct secondary vertices in a jet .. Find points of high overlap tracks
cЮD D primary
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bЮBЮD D B primary

uds

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#Ver tices reconstructed


Using the reconstructed vertices, we can do 1) Heavy-flavor tagging
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2) Charge separation
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bottom charm uds

BB+ B0

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PT corrected Ver tex Mass (GeV)

Vertex Mass

Vertex Charge

For example..


Analysis example with b-tag:
Reconstruction of t-quark mass in tt 6jets event Without b-tag
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With b-tag

Signal BG
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Mass (GeV/c2)

Mass (GeV/c2)

(FastMC)


LCD Root Event Display

FastMC (e+e- Ю ZH)


LCD Root Event Display

FullMC (e+e- Ю tt)


Event structure at LCD Root
Event Event Header event number ... McParticles Beam parameters polarization, IP position ... Generator level particle information Raw data (Full) Reconstructed Data Tracks Clusters Based on TClonesArray VXDHits TrackerHits CalHits


Summary
LCD group has constructed simulation/analysis tools for the future Linear Collider experiments ·The simulation/analysis tools based on ROOT ·LCD Root handles several I/O ... Some of them require STL (can be worked ROOT V3.00 or later) Ю work well!

·There is a LCD Root tutorial page! (Under construction) URL: http://www-sldnt.slac.stanford.edu/nld/New/Docs /LCD_Root/root.htm


Future Plan
· GEANT4 · GUI · Support Windows We are happy to collaborate with other exp. groups to develop analysis tools!! ( Currently LCD Root is maintained by 2 people ... )