Latest results frompp collisions at D

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Latest results from?pp collisions at DØ

• Last updated October 9, 2001
• John Womersley
• womersley_at_fnal.gov

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Commissioning timeline
Action
Dates
Continue 36 x 36 running With detector as
described before.
July 26
Done

• Increase L3 rate from 4 Hz to 100Hz
• Complete L1 Cal
• Start bringing up L2 trigger partially

By August 15
In Progress
NOW
Done
Take data commission Offline software with real
data Calibration Alignment
Run until Oct 8
Install AFE8 boards other completion
Oct 8 - Nov 16
In Preparation
36x36 stores Commission CFT L1 track trigger
November
36x36 fine tune stabilize ? stable operation
December January 2002
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Dimuon Z candidate

• Two muons recoiling against a jet
• Dimuon mass 55 GeV

Onne Peters NIKHEF
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J/? ???- candidates
Dimuons reconstructed in the forward region
On peak
Off peak ?bb?
??
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Muons in jets
Onne Peters, NIKHEF
Back to back calorimeter jets
Muon in jet (b candidate) Hits in A,B,C layers
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Jets
?
jet
? candidate

• This type of event is used to derive the jet
  energy calibration

jet
DØ
DØ
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Level 3 calorimeter trigger
EM clusters, pT gt 10 GeV Isolated, EM fraction gt
0.9 ? lt 1.1
Jets, pT gt 15 GeV R 0.7 cone ? lt 1.1
fail (prescaled)
fail (prescaled)
pass
pass
Volker Buescher Mainz
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Z ? ee candidates
2 EM objects, ET gt 20 GeV, isolation and shower
shape cuts
mZ
(uncalibrated energy scale)
Leo Chan, Rochester
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W? e? candidates
EM cluster with track
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Just for fun . . .
DØ W 2 jet (Higgs!) candidate, October 2001
Jet 1 ETraw 17 GeV
Electron
Electron
Jet 1
Jet 2 ETraw 13 GeV
Jet 2
Jet ET corrections will be large
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Silicon Detector
H1
B1
H4
B4
B6
North
F1
South
F12
F11
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DØ silicon performance
DØ silicon performance
Primary vertex
J/? signal from silicon tracking
Single Run
First reconstructed tracks April 2001
K0 signal from silicon tracking
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Fiber tracker readout
Readout under detector
Photoelectron peaks in final electronics in DØ
1 pe 7 fC
Clear Fiber Waveguides carry the signals to
VLPCs Solid state photon counters Operate at
LHe temperature
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The work of many people...
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(No Transcript)
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Detector in Collision Hall January 2001
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Detector in Collision Hall January 2001
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DØ data in the news
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?pp ? WH ??bb ? e?
Missing ET
EM cluster
Electron Track
p ?
??p
Hits in Silicon Tracker (for b-tagging)
Two b-jets from Higgs decay
Calorimeter Towers