Transcript Document

Atlantis and the Inner Detector
Gary Taylor (UCSC) 7/3/2003
Outline
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Tracking in the inner detector at design luminosity
Reconstruction of secondary vertices
Association of ID tracks to the calorimeters
Association of ID tracks to muon tracks
Future plans
Check track reconstruction in difficult design luminosity event
• Selected event has two high pt (>560GeV) jets ( DC1dataset 2045)
• Luminosity
• Silicon space points
• TRT hits
• Reconstructed tracks
• Reconstructed in
1034
27,000
240,000
1,200
20 minutes
2D projections of Inner Detector data not very useful at design luminosity
(TRT -ve barrel only)
Explanation of the fh and V-Plot projections
f
r = rMax
V-Plot
Draw each space point
twice at
F,h+k*(r-rMax)
and
F,h-k*(r-rMax)
r = 2 cm
h
low p, -ve
Distorted V’s
track not from IP
high p, +ve
 3D information
For tracks can judge
•f
•h
• pt (slope of V arms)
• charge ( L -ve
V +ve)
V-Plot silicon space points
Fh calorimeters
Filtering of space points available inside Atlantis
Filter space points
with a histogram
based technique
which selects hits
consistent with
tracks originating
from the primary
vertex.
Time = 1 sec/event
ATLAS note in
preparation
Filtered hits
xKalman tracks
22 tracks
225 GeV
20 tracks
165 GeV
True tracks
34 tracks
410 GeV
28 tracks
270 GeV
Unreconstructed
true tracks
Tracks lost in core of central jet
Unused filtered hits
… and true tracks
True tracks not
reconstructed
Lost tracks in forward jet
Good unused filtered
All unused filtered
hits on true tracks
hits
Zoom next track feature – allows easy checking of tracking
True tracks – association not yet available for reconstructed
Clusters from Silicon Strips (work in progress)
f
f
stereo clusters
track
space point
rf clusters
Need … cluster-to-track association
z
r
Clusters from a single module
Ghost hits
Identifying secondary vertices
Look for a group of nearby kinked V’s in the VPlot
True tracks
Reconstructed tracks
D
B
Reconstructed and simulated secondary vertices in XY plane (t-bln)
B
D
3s error
ellipse
Reconstructed tracks
Primary
True tracks
Secondary vertex region best displayed in abstract 3D Box
Plane
containing
primary
vertex
Plane
containing
secondary
vertex
secondary
vertex
primary
vertex
Ellipses
represent
track
error (1s)
Single electron – 30 GeV pT (DC1)
LAr Presampler
Pt=29.3 GeV
E =31.2 GeV
Cell geometry
LAr Layer 1
LAr Layer 2
LAr Layer 3
Track
(enters LAr here)
Area a E
Island (guides eye)
Muon tracking with Moore – work in progress
Need to follow muon tracks in magnetic field
MDT
RPC
Comparison of muon and inner detector track fits
f
p = 28 GeV
Dp = 5 GeV
Df = 1.5 deg
Dh = 0.02
muon
tracks
Inner detector
tracks
p = 25 GeV
Dp = 4 GeV
Df = 1 deg
Dh = 0.01
V-Plot allows comparison
of f, h and pt
h
Future plans in Inner detector (near term)
• add tracks from iPatRec
• add reconstructed track-to-hit association
• improve presentation of silicon strip data
• add histogram to search for high pt tracks in TRT
Conclusions
• many aspects of the reconstruction may be checked using Atlantis
• much more available soon
• followed by new public release
• users and their feedback/requests are very welcome
• tutorial foreseen during May software workshop
• happy to help produce event displays for user presentations
Special thanks to
• Jon Couchman (Access to data from Athena –JiveXML)
• Hans Drevermann (Ideas and advice)