DØ's Top Quark Physics Results

Conveners:  Frédéric Déliot (CEA-Saclay) and
Christian Schwanenberger (University of Manchester)

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  Channel   Method Measurement Uncertainty Integrated
Luminosity
[fb–1]		 Documentation
DZero's posterior density distribution
• March 2009            		 DZero's discriminant output (all channels combined)
• March 2009        
  
Single Top Quark
Production

 DZero's significance plot
           • March 2009		 DZeros cross section measurements
     • March 2009
Lepton+jets Analyses with
boosted decsion trees,
Bayesian neural networks,
matrix elements,
and their combination		 σ(tb+tqb) = 3.94 ± 0.88 pb
5.0 standard deviation significance
(mtop = 170 GeV)

|Vtb| > 0.78   at 95% C.L.    (prior: 0 ≤ |Vtb|2 ≤ 1)
|VtbfL1| = 1.07 ± 0.12    (prior: |Vtb|2 ≥ 0)		 ± 22% 2.3
"Observation of
single top quark
production"

Submitted to PRL
3/4/09
Figures
Lepton+jets Wtb couplings
(single top and
tt W helicity)		 Limits set on
left-handed and right-handed
vector and tensor couplings		 95% C.L. 0.9 PRL 102, 092002 (2009)
3/4/09
Figures
H+→tb search Type I 2HDM model excluded for
M(H+ = 180–185 GeV
and tan(β) = 20–70 approx
and limits on Types II and III set		 95% C.L. Submitted to PRL
7/8/08
Figures
Wtb couplings Limits set on
left-handed and righthanded
vector and tensor couplings		 95% C.L. PRL 101, 221801 (2008)
11/25/08
Figures
W'→tb search M(W'(left)→ln,qq) > 731 GeV
M(W'(right)→ln,qq) > 739 GeV
M(W'(right)→qq) > 768 GeV		 95% C.L. PRL 100, 211803 (2008)
5/30/08
Figures
Combination of
DT, new-ME,
and new-BNN		 sigma(tb+X,tqb+X) = 4.7 ± 1.3 pb
(3.6 std. dev. significance) 		± 28% PRD 78, 012005 (2008)
7/14/08
Figures
Matrix elements  
sigma(tb+X,tqb+X) = 4.8 +1.6 –1.4 pb
 		 +33% –29%
Bayesian neural networks  
sigma(tb+X,tqb+X) = 4.4 +1.6 –1.4 pb
 		 +36% –32%
Boosted decision trees sigma(tb+X,tqb+X) = 4.9 ± 1.4 pb
(3.4 std. dev. significance)

s-channel:  σ(tb+X) = 1.0 ± 0.9 pb
t-channel:  σ(tqb+X) = 4.2 +1.8 –1.4 pb		 ± 29%


±90%
+43% –33%		 "Evidence for production
of single top quarks"

PRL 98, 181802 (2007)
5/1/07
Figures
Plain-english summary
Analysis details
Matrix elements  
sigma(tb+X,tqb+X) = 4.6 +1.8 –1.5 pb
 		 +39% –33%
Bayesian neural networks  
sigma(tb+X,tqb+X) = 5.0 ± 1.9 pb
 		 ± 38%
Lepton+jets FCNC search κgc/Λ < 0.15 TeV-1
κgu/Λ < 0.037 TeV-1		 95% C.L. 0.23 PRL 99, 191802 (2007)
11/6/07
Figures
W' search M(W'(right)→ln,qq) > 630 GeV
M(W'(right)→qq) > 670 GeV		 95% C.L. PLB 641, 423 (2006)
9/28/06
Figures
Plain-english summary
Analysis details
Cuts s-channel:  sigma(tb) < 10.6 pb
t-channel:  sigma(tqb) < 11.3 pb		 95% C.L. PRD 75, 092007 (2007)
5/29/07
Figures
(Includes NN result below)
Neural networks s-channel:  sigma(tb) < 6.4 pb
t-channel:  sigma(tqb) < 5.0 pb		 95% C.L. PLB 622, 265 (2005)
7/21/05
Figures
Plain-english summary
Analysis details
DZero's top mass combination plot  
• DØ's top quark mass  
combination  
July 2008  
 World average top mass plot  
• World average top  
mass combination  
August 2008  
 Top Quark Mass
    Higgs boson mass allowed range
• LEP EW Working Group
• July 2008  
 Constraints on Higgs boson mass from top and W masses
• Predictions in the MSSM
• W mass in the MSSM
  March 2008
Lepton+jets,
dilepton,
and alljets		 Many methods World average measurement
173.1 ±0.6 (stat) ±1.1 (syst) GeV		 ±0.75% ≤ 3.6 3/13/09
arXiv:0903.2503
Lepton+jets
and dileptons		 Many methods DØ's measurements combined
174.2 ± 0.9 (stat) ± 1.5 (syst) GeV		 ±0.98% ≤3.6 3/13/09
Conference note
Figures
Lepton+jets Matrix elements with
in-situ JES calibration
(NN b-tagging)		 171.5 ± 1.8 (stat+JES) ± 1.1 (syst) GeV ± 1.2% 1.0 PRL 101, 182001 (2008)
10/29/08
Figures
Lepton+jets Ideogram
(lifetime b-tagging and
topological selection)		 173.7 ± 4.4 (stat+JES) +2.1 –2.0 (syst) GeV ± 2.8% 0.42 PRD 75, 092001 (2007)
5/11/07
Figures
Lepton+jets Matrix element
with in-situ JES calibration
(lifetime b-tagging)		 170.3 +4.1 –4.5 (stat+JES) +1.2 –1.8 (syst) GeV +2.5% –2.8% 0.37 PRD 74, 092005 (2006)
11/27/06
Figures
Matrix element
with in-situ JES calibration
(topological selection)		 169.2 +5.0 –7.4 (stat+JES) +1.5 –1.4 (syst) GeV +3.1% –4.5%
Dileptons Neutrino weighting
(NN b-tagging and
topological selection)		 176.0 ± 5.3 (stat) ± 2.0 (syst) GeV ±3.2% 1.0 7/25/08
Conference note
Figures
Matrix weighting
(topological)		 175.2 ± 6.1 (stat) ± 3.4 (syst) GeV ± 4.0% 1.0 8/9/07
Conference note
Figures
Dileptons Matrix weighting
(lifetime b-tagging
and untagged)		 176.2 ± 9.2 (stat) ± 3.9 (syst) GeV ± 5.7% 0.37 PLB 655, 7 (2007)
9/6/07
Figures
Plain-english summary
Neutrino weighting
(topological selection
and lepton+track)		 179.5 ± 7.4 (stat) ± 5.6 (syst) GeV ± 5.2%
Combination of the
above two results
(various)		 178.1 ± 6.7 (stat) ± 4.8 (syst) GeV ± 4.6%
Dileptons
and tau+lepton		 From the ttbar
cross section		 171.5 +9.9 –8.8 (stat+syst) GeV +5.8% –5.1% 1.0 Submitted to PLB
1/24/09
Figures
Lepton+jets Determined from
ttbar cross section		 170 ± 7 GeV ± 4.1% 0.9 PRL 100, 192004 (2008)
5/15/08
Figures
DZero's top pair cross section plot  
• August 2008        
 DZero and CDF's ttbar cross sections summary plot
• April 2008        
 Top Pair Production Cross Section

Results quoted for mtop = 175 GeV		    DZero 's cross section versus mass plot
       • March 2008
Lepton+jets,
dileptons, and
tau+lepton		 NN b-tagging
and topological		 7.83  +0.46 –0.45 (stat) +0.64 –0.53 (syst) ± 0.48 (lumi) pb +12% –11% 1.0 7/25/08
Conference note
Figures
Tau+lepton NN b-tagging 7.3  +1.3 –1.2 (stat) +1.2 –1.1 (syst) ± 0.5 (lumi) pb +25% –23% 2.2 7/9/08
Conference note
Figures
Lepton+track
and dileptons		 NN b-tagging
and topological		 6.2  ± 0.9 (stat) +0.8 –0.7 (syst) ± 0.4 (lumi) pb +20% –19% 1.0 8/9/07
Conference note
Figures
Lepton+jets Muon b-tagging 7.3  +2.0 –1.8 (stat+syst) ± 0.4 (lumi) pb +28% –25% 0.42 10/27/06
Conference note
Figures
Tau+jets Lifetime tagging 5.1  +4.3 –3.5 (stat) ± 0.7 (syst) ± 0.3 (lumi) pb +86% –70% 0.35 9/13/06
Conference note
Figures
Dileptons and
tau+lepton		 NN b-tagging
and topological		 7.09  +0.98 –0.92 (stat) +0.78 –0.57 (syst) +0.62 –0.49 (lumi) pb +20% –17% 1.0 Submitted to PLB
1/24/09
Figures
Lepton+jets NN b-tagging
and topological		 World's most precise measurement
7.62  ± 0.85 pb for mtop = 172.6 GeV
7.42  ± 0.53 (stat) ± 0.46 (syst) ± 0.45 (lumi) pb
for mtop = 175 GeV		 ± 11% 0.9 PRL 100, 192004 (2008)
5/15/08
Figures
Lepton+jets NN b-tagging
and topological
 (simultaneous with B(t→Wb)/B(t→Wq),
see below)		 8.18  +0.90 –0.84 (stat + syst) ± 0.50 (lumi) pb +13% –12% 0.9 PRL 100, 192003 (2008)
5/14/08
Figures
Dileptons Topological 7.4  ± 1.4 (stat) ± 0.9 (syst) ± 0.5 (lumi) pb ± 23% 0.42 PRD 76, 052006 (2007)
9/28/07
Figures
Lepton+jets Topological 6.4  +1.3 –1.2 (stat) ± 0.7 (syst) ± 0.4 (lumi) pb +24% –23% 0.42 PRD 76, 092007 (2007)
11/27/07
Figures
Alljets Lifetime tagging 4.5  +2.0 –1.9 (stat) +1.4 –1.1 (syst) ± 0.3 (lumi) pb +55% –49% 0.41 PRD 76, 072007 (2007)
10/19/07
Figures
Lepton+jets Lifetime tagging 6.6  ± 0.9 (stat+syst) ± 0.4 (lumi) pb ± 15% 0.42 PRD 74, 112004 (2006)
12/26/06
Figures
Lepton+jets Lifetime tagging 8.6  +1.6 –1.5 (stat+syst) ± 0.6 (lumi) pb +20% –19% 0.23 PLB 626, 35 (2005)
9/15/05
Figures
Plain-english summary
Lepton+jets Topological 6.7  +1.4 –1.3 (stat) +1.6 –1.1 (syst) ± 0.4 (lumi) pb +32% –26% 0.23 PLB 626, 45 (2005)
9/15/05
Figures
Plain-english summary
Dileptons Topological 8.6  +3.2 –2.7 (stat) ± 1.1 (syst) ± 0.6 (lumi) pb +40% –35% 0.23 PLB 626, 55 (2005)
9/15/05
Figures
Plain-english summary
 
Other Top Quark Properties
 
Lepton+jets SM Higgs
produced with tt
with H0→bb		 σ(ttH) < 64 × SM value
for MHiggs> = 115 GeV
 2.1 7/28/08
Conference note
Figures
Lepton+jets,
dileptons,
and tau+lepton		 Decay to charged
Higgs boson		 B(t→H+b) < 0.20 (95% CL) (leptophobic H+)
B(t→H+b) < 0.12 to 0.20 (95% CL) (tauonic H+)		 1.0 7/25/08
Conference note
Figures
Lepton+jets
and dileptons		 Right-handed W's f0 = 0.490 ±0.106 (stat) ±0.085 (syst)
f+ = 0.110 ±0.059 (stat) ±0.052 (syst)		 2.7 7/25/08
Conference note
Figures
Lepton+jets Search for
tt resonances from
leptophobic Z' bosons		 MZ' < 760 GeV
excluded at 95% CL for ΓZ' = 1.2% MZ'		 2.1 3/7/08
Conference note
Figures
Lepton+jets
and dileptons		 Cross section ratio σ(pp→tt)l+jets/σ(pp→tt)ll = 1.21 +0.27 −0.26 (stat + syst) 1.0 8/9/07
Conference note
Figures
Lepton+jets Scalar top
pair production		 Limits on scalar top masses between 130 to 190 GeV
and chargino masses of 90 to 150 GeV		 0.9 Accepted in PLB
2/17/09
Figures
Plain-english summary
Lepton+jets Wtb couplings
(single top and
tt W helicity)		 Limits set on
left-handed and right-handed
vector and tensor couplings		 0.9 PRL 102, 092002 (2009)
3/4/09
Figures
Lepton+jets Search for
tt resonances from
leptophobic Z' bosons		 MZ' < 700 GeV
excluded at 95% CL for ΓZ' = 1.2% MZ'		 0.9 PLB 668, 98 (2008)
8/22/08
Figures
Lepton+jets Measurement of R =
B(t→Wb)/B(t→Wq)
 (simultaneous with
tt cross section,
see above)		 R = 0.97 +0.09 –0.08 (stat+syst) ,  R > 0.79  (95% CL)
|Vtb| > 0.89  (95% CL)  (if 3x3 CKM is unitary)		 0.9 PRL 100, 192003 (2008)
5/14/08
Figures
Lepton+jets Forward-backward
charge asymmetry in
tt production
and Z' resonance limit		 (12  ± 8 (stat) ± 1 (syst) )% 0.9 PRL 100, 142002 (2008)
4/9/08
Figures
Lepton+jets
and dileptons		 Right-handed W's f0 = 0.425 ±0.166 (stat) ±0.102 (syst)
f+ = 0.119 ±0.090 (stat) ±0.053 (syst)		 1.0 PRL 100, 062004 (2008)
2/14/08
Figures
Plain-english summary
Lepton+jets
and dileptons		 Right-handed W's f+ = 0.056 ±0.080 (stat) ±0.057 (syst)
f+ < 0.23  (95% CL)		 0.37 PRD 75, 031102(R) (2007)
2/5/07
Figures
Lepton+jets Top quark charge
 4e/3 excluded at 92% CL
Fraction of exotic quark pairs < 0.80  (90% CL)		 0.37 PRL 98, 041801 (2007)
1/22/07
Figures
Clarification
Lepton+jets Measurement of R =
B(t→Wb)/B(t→Wq)		 R = 1.03 +0.19 –0.17 (stat+syst)
R > 0.61 and |Vtb| > 0.78  (95% CL)		 0.23 PLB 639, 616 (2006)
7/24/06
Figures
Lepton+jets Right-handed W's
(topological and lifetime)		 Fraction of right-handed W's in top decays = f+
f+= 0.00 ± 0.13 (stat) ± 0.07 (syst)
f+ < 0.25  (95% CL)		 0.23 PRD 72, 011104 (2005)
7/29/05
Figures
Plain-english summary

This page created by Ann Heinson
Last update: March 16, 2009