Latest PRELIMINARY Results from Run 2 at D

1
Latest PRELIMINARY Results from Run 2 at DØ

• Last updated Jan. 11, 2002
• Boaz Klima
• (klima_at_fnal.gov)

2
Z ? ee- Candidates
2 EM objects, ET gt 20 GeV, isolation and shower
shape cuts
L1.2pb-1
e
e
(uncalibrated energy scale)
Leo Chan, Rochester
3
W? e? Candidates
Vishnu Zutshi, NIU Leo Chan, Rochester
ET
e
EM cluster with track
mT(e,n) L0.7pb-1 (uncalibrated energy scale)
EM cluster with track
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Higgs Candidate (just kidding)
DØ W 2 jet candidate
Jet 1 ETraw 17 GeV
ET
Electron
Electron
Jet 1
Jet 2
Jet 2 ETraw 13 GeV
Jet ET corrections will be relatively large
5
Z ? mm- Candidate

• Two muons recoiling against a jet
• Dimuon invariant mass 55 GeV (with large
  uncertainty)

Onne Peters NIKHEF
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J/? ???-
Di-muons reconstructed in the forward region
Roger Moore and Adam Yurkewicz, MSU
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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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bb (b ? m) Candidate

• Two jets tagged with muons
• Jet 1 ET 18 GeV, pTm 7.4 GeV, pTrel .30
  GeV
• Jet 2 ET 13 GeV, pTm 5.4 GeV, pTrel .24
  GeV
• and in case you wonder, Mmm 12 GeV and Mjj
  29 GeV

R-Z view
X-Y view
3-D view
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Muons and Jets
Onne Peters, NIKHEF
Muon Jet cross section (partially
corrected)
PTRel Distribution (using Run 1 templates)
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Jetty Events
Using R0.7 Cone Algorithm with Run 1 corrections
Alexander Kupco, Prague

• 3-jet event
• ETjet1310GeV
• ETjet2240GeV
• ETjet3110GeV
• ET8GeV

• 2-jet event
• ETjet1230GeV
• ETjet2190GeV

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Jet Distributions
Using R0.7 Cone Algorithm (energies partially
corrected)
Alexander Kupco, Prague
Dijet Invariant Mass
Single Jet PT
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Jet Energy Calibration
Ia Iashvili, Riverside
Calorimeter Response in CCEC
?
jet
Pre-shutdown Data
Post-shutdown Data
E' ETg x cosh(hjet)
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J/? ?ee-
Di-electrons reconstructed in CFT and SMT
Sergey Burdin, LAL
(uncalibrated EM energy scale)
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EM Energy Calibration
Marie-Claude Cousinou, Marseille
Data - before Correction
Data - after Correction
Monte Carlo P30.959 corresponds to a mass
of 87.5 GeV
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Ks ?pp-
Tracks reconstructed in the SMT detector
Brad Abbott, Oklahoma
Black histogram opposite-sign tracks Red
histogram same-sign tracks Dotted curve fit
to background Full curve fit to signal
background
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Ks (?pp-) Lifetime
Tracks reconstructed in the SMT detector
Ariel Schwartzman, Buenos Aires
l ( )
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Hits in SMT and CFT
Avto Kharchilava, Notre Dame
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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