Transcript XXXVI International Meeting on Fundamental Physics Physics at the Tevatron From IMFP2006 → IMFP2008 Rick Field University of Florida (for the CDF & D0 Collaborations) 2nd Lecture Bosons,

XXXVI International Meeting on
Fundamental Physics
Physics at the Tevatron
From IMFP2006 → IMFP2008
Rick Field
University of Florida
(for the CDF & D0 Collaborations)
2nd Lecture
Bosons, Top, and Higgs
Palacio de Jabalquinto, Baeza, Spain
CDF Run 2
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 1
Tevatron Performance
The data collected since IMFP 2006 more than doubled
the total data collected in Run 2!
IMFP 2006
~1.5 fb-1 delivered
~1.2 fb-1 recorded
IMFP 2008
~3.3 fb-1 delivered
~2.8 fb-1 recorded
~1.6 fb-1
Integrated Luminosity per Year
23 tt-pairs/month!
 Luminosity Records (IMFP 2006):
 Highest Initial Inst. Lum: ~1.8×1032 cm-2s-1
 Integrated luminosity/week: 25 pb-1
 Integrated luminosity/month: 92 pb-1
IMFP2008 - Day 2
February 5, 2008
 Luminosity records (IMFP 2008):
 Highest Initial Inst. Lum: ~2.92×1032 cm-2s-1
 Integrated luminosity/week: 45 pb-1
 Integrated luminosity/month: 165 pb-1
Rick Field – Florida/CDF/CMS
Page 2
Many New Tevatron Results!
Some of the CDF Results since IMFP2006













IMFP2008 - Day 2
February 5, 2008
Observation of Bs-mixing: Δms = 17.77 ± 0.10 (stat) ± 0.07(sys).
Observation of new baryon states: Sb and Xb.
Observation of new charmless: B→hh states.
Evidence for Do-Dobar mixing .
Precision W mass measurement: Mw = 80.413 GeV (±48 MeV).
cannot
cover
the(±2.2) GeV.
PrecisionI Top
mass possibility
measurement:
Mtop =all
170.5
great physics
results
from
W-width measurement:
2.032
(±0.071)
GeV.the
Tevatron
since
IMFP
WZ discovery
(6-sigma):
s = 5.0
(±1.7)2006!
pb.
I will
show a few of the results!
ZZ evidence
(3-sigma).
Single Top evidence (3-sigma) with 1.5 fb-1: s = 3.0 (±1.2) pb.
|Vtb|= 1.02 ± 0.18 (exp) ± 0.07 (th).
Significant exclusions/reach on many BSM models.
Constant improvement in Higgs Sensitivity.
Rick Field – Florida/CDF/CMS
Page 3
Z-boson Cross Section (CDF)
IMFP2006
QCD
Drell-Yan
 Impressive agreement between experiment
and NNLO theory (Stirling, van Neerven)!
s(Z→e+e-)
IMFP2008 - Day 2
February 5, 2008
CDF (pb)
NNLO (pb)
254.93.3(stat)4.6(sys)15.2(lum)
252.35.0
Rick Field – Florida/CDF/CMS
Page 4
Z-boson Cross Section (CDF)
IMFP2006
 Impressive agreement between experiment and NNLO theory
(Stirling, van Neerven)!
s(Z→m+m-)
IMFP2008 - Day 2
February 5, 2008
CDF (pb)
NNLO (pb)
261.22.7(stat)6.9(sys)15.1(lum)
252.35.0
Rick Field – Florida/CDF/CMS
Page 5
Z-Boson Rapidity Distribution
 Measure ds/dy for



since IMFP2006
Z→e+e-.
Use electrons
in the central (C) and plug (P) calorimeter.
Parton momentum fractions x1 and x2 determine the Z boson
rapidity, yZ.
Production measurement in high yZ region probes high x
region of PDF’s.
Plug-plug electrons, ZPP, are used to probe the high x region!
1.1fb-1 91,362 events 66 < MZ < 116 GeV
CDF
Events
Zcc
IMFP2008 - Day 2
February 5, 2008
ZCC
ZCP
ZPP
28,097
46,676
16,589
Zcp
Rick Field – Florida/CDF/CMS
Plug-Plug
electrons!
Zpp
Page 6
Z-Boson Rapidity Distribution
since IMFP2006
 CDF measured ds/dy for Z/g*


compared with an NL0 calculation
using CTEQ6.1M PDF.
The NLO theory is scaled to the
measured s(Z)!
No PDF or luminosity uncertainties
included.
NLO+ +NNL0
CTEQ6.1
PDF
NLL0
MRST
PDF
s(Z→e+e-)
IMFP2008 - Day 2
February 5, 2008
CDF (pb)
263.3±0.9(stat)±3.8(sys)
Rick Field – Florida/CDF/CMS
NLO + MRST PDF
NNLO (pb)
252.35.0
Page 7
The Z→tt Cross Section (CDF)
 Taus are difficult to reconstruct at hadron colliders
• Exploit event topology to suppress backgrounds (QCD & W+jet).
• Measurement of cross section important for Higgs and SUSY analyses.
Signal
cone
 CDF strategy of hadronic τ reconstruction:
• Study charged tracks define signal and isolation cone (isolation = require no
tracks in isolation cone).
• Use hadronic calorimeter clusters (to suppress electron background).
• π0 detected by the CES detector and required to be in the signal cone.
 CES: resolution 2-3mm, proportional strip/wire drift chamber at 6X0 of
EM calorimeter.
Isolation
cone
 Channel for Z→ττ: electron + isolated track
• One t decays to an electron: τ→e+X (ET(e) > 10 GeV) .
• One t decays to hadrons: τ → h+X (pT > 15GeV/c).
 Remove Drell-Yan e+e- and apply event topology cuts for non-Z
background.
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 8
The Z→tt Cross Section (CDF)
 CDF Z→ττ (350 pb-1): 316 Z→ττ candidates.
 Novel method for background estimation: main contribution QCD.
 τ identification efficiency ~60% with uncertainty about 3%!
1 and 3 tracks,
opposite sign
same sign,
opposite sign
s(Z→t+t-)
IMFP2008 - Day 2
February 5, 2008
IMFP2006
CDF (pb)
NNLO (pb)
264
± 23 (stat) ± 14 (sys) ± 15 (lum)
26520(stat)21(sys)15(lum)
252.35.0
Rick Field – Florida/CDF/CMS
Page 9
Higgs → tt Search (CDF)
140 GeV
Higgs Signal!
IMFP2006
 Data mass distribution agrees with SM expectation:
• MH > 120 GeV: 8.4±0.9 expected, 11 observed.
 Fit mass distribution for Higgs Signal (MSSM scenario):
• Exclude 140 GeV Higgs at 95% C.L.
• Upper limit on cross section times branching ratio.
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 10
Higgs → tt Search (CDF)
since IMFP2006
No Significant Excess of events above SM background is observed!
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 11
W-boson Cross Section (CDF)
 Extend electron coverage to the forward
region (1.2 < |h| < 2.8)!
IMFP2006
48,144 W candidates ~4.5% background
overall efficiency of signal ~7%
s(W)/s(Z)
s(W)
CDF
NNLO
10.920.15(stat)0.14(sys)
10.690.08
L
CDF (pb)
NNLO(pb)
Central
electrons
72 pb-1
277510(stat)53(sys)167(lum)
268754
Forward
electrons
223 pb-1
281513(stat)94(sys)169(lum)
268754
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 12
W-Boson Mass Measurement
since IMFP2006
 The Challenge:
 Do not know neutrino pz.
 No full mass reconstruction possible.
 Extract from a template fit to PT, MT, and
Missing ET.
 Transverse mass:
MW = 80413 ± 48 MeV/c2
Single most precise measurement to date!
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 13
W-Boson Width Measurement
since IMFP2006
 Model transverse mass distribution
over range 50-200 GeV.
 Normalize 50-90 GeV and fit for the width in the high
MT region 90-200 GeV.
 The tail region is sensitive to the width of the Breit
Wigner line-shape.
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 14
 There are more u-quarks than d-quarks at high x in

the proton and hence the W+ (W-) is boosted in the
direction of the incoming proton (antiproton).
Measuring the W± asymmetry constrains the PDF’s!
u
p d
u
e+
W+
d
u
u
xG(x,Q2)
W Production Charge Asymmetry
Q2 = 100 GeV2
MRST2004NLO
u
d
p
10-3
e
W-
10-2
10-1
1
W+
ds  / dyW  ds  / dyW
A( yW ) 
ds  / dyW  ds  / dyW
antiproton proton
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
y
Page 15
x
W Production Charge Asymmetry
 Since the longitudinal momentum of the neutrino,


pL(), is not known the W rapidity cannot be
reconstructed.
So previously one looked at the the electron
charge asymmetry.
The V-A structure of the W+ (W-) decay favors a
backward e+ (forward e-) which “dilutes” the W
charge asymmetry!
since IMFP2006
 New CDF measurement performed in W→e


channel.
pL() is determined by constraining MW = 80.4
GeV leaving two possible yW solutions. Each
solution receives a probability weight according
to the V-A decay structure and the W crosssection, s(yW).
The process is iterated since s(yW) depends on the
asymmetry.
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 16
W + g Cross Sections (CDF)
IMFP2006
ET(g) > 7 GeV
R(lg) > 0.7
s(W+g)*BR(W->l)
IMFP2008 - Day 2
February 5, 2008
CDF (pb)
NLO (pb)
19.71.7(stat)2.0(sys)1.1(lum)
19.31.4
Rick Field – Florida/CDF/CMS
Page 17
W + g Cross Sections (CDF)
since IMFP2006
ET(g) > 7 GeV
R(lg) > 0.7
s(W+g)*BR(W->l)
IMFP2008 - Day 2
February 5, 2008
CDF (pb)
NLO (pb)
18.03±0.65(stat)±2.55(sys)
±1.05(lum)
19.71.7(stat)2.0(sys)1.1(lum)
19.31.4
Rick Field – Florida/CDF/CMS
Page 18
Z + g Cross Sections (CDF)
IMFP2006
Note: s(Wg)/s(Zg) ≈ 4
while s(W)/s(Z) ≈ 11
ET(g) > 7 GeV
R(lg) > 0.7
s(Z+g)*BR(Z->ll)
IMFP2008 - Day 2
February 5, 2008
CDF (pb)
NLO (pb)
5.30.6(stat)0.3(sys)0.3(lum)
5.40.3
Rick Field – Florida/CDF/CMS
Page 19
Z + g Cross Sections (CDF)
since IMFP2006
390 events
ET(g) > 7 GeV
R(lg) > 0.7
Meeg > 40 GeV/c2
s(Z+g)*BR(Z->ee)
IMFP2008 - Day 2
February 5, 2008
CDF (pb)
NLO (pb)
4.90.3(stat)0.3(sys)0.3(lum)
4.70.4
Rick Field – Florida/CDF/CMS
Page 20
The W+W Cross-Section
IMFP2006
Campbell & Ellis 1999
pb-1
CDF (pb)
NLO (pb)
s(WW) CDF
184
14.6+5.8(stat)-5.1(stat)1.8(sys)0.9(lum)
12.40.8
s(WW) DØ
240
13.8+4.3(stat)-3.8(stat)1.2(sys)0.9(lum)
12.40.8
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 21
The W+W Cross-Section (CDF)
IMFP2006





WW→dileptons + MET
Two leptons pT > 20 GeV/c.
Z veto.
MET > 20 GeV.
Zero jets with ET>15 GeV
and |h|<2.5.
We are beginning to study the details
of 95 events with
Observe
37.2 background!
Di-Boson production at the Tevatron!
s(WW)
L
CDF (pb)
NLO (pb)
825 pb-1
13.72.3(stat)1.6(sys)1.2(lum)
12.40.8
Missing ET!
IMFP2008 - Day 2
February 5, 2008
Lepton-Pair Mass!
Rick Field – Florida/CDF/CMS
ET Sum!
Page 22
WW+WZ Cross-Section
since IMFP2006
NLO Theory
σWW × Br(W→l, W→jj) = 12.4 pb × 0.146 = 1.81 pb
σWZ × Br(W→l, Z→jj) = 3.96 pb × 0.07 = 0.28 pb
s(WW+WZ)×BR(lvjj)
IMFP2008 - Day 2
February 5, 2008
CDF (pb)
NLO (pb)
1.47 ± 0.77(stat) ± 0.38(sys)
2.1 ± 0.2 pb
Rick Field – Florida/CDF/CMS
Page 23
The Z+W, Z+Z Cross Sections
IMFP2006
W+Z → trileptons + MET
Observe 2 events with a
background of 0.9±0.2!
Upper Limits
W+Z, Z+Z
Limit (pb)
NLO (pb)
CDF (194 pb-1) sum
< 15.2 (95% CL)
5.00.4
DØ (300 pb-1) W+Z
< 13.3 (95% CL)
3.70.1
CDF (825 pb-1) W+Z
< 6.34 (95% CL)
3.70.1
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 24
The W+Z Cross Section
since IMFP2006
Strategy
 Search for events with 3 leptons and missing
energy.
 Small cross-section but very clean signal.
 Anomalous cross-section sensitive to non SM
contributions.
3.0 σ significance!
s(W+Z)
IMFP2008 - Day 2
February 5, 2008
L
CDF (pb)
NLO (pb)
1.9 fb-1
4.3±1.3(stat) ±0.2(sys) ±0.3(lum)
3.70.3
Rick Field – Florida/CDF/CMS
Page 25
The Z+Z Cross Section
since IMFP2006
Strategy:
 Search for events with either 4 leptons
2 leptons and significant missing ET.
 Calculate a Prob(WW) or Prob(ZZ) based on event
kinematics and LO cross section.
 Construct a likelihood ratio.
 Fit to extract the ll signal.
or
ZZ
ZZdecaying
decayinginto
into2 4
leptons
leptons+ MET
3.0 σ significance!
s(Z+Z)
IMFP2008 - Day 2
February 5, 2008
L
CDF (pb)
NLO (pb)
1.9 fb-1
0.75+0.71-0.54
1.4±0.1
Rick Field – Florida/CDF/CMS
Page 26
Higgs → W+W
 We are within a factor of two of
the standard model
Higgs (160 GeV) → WW!
IMFP2008 - Day 2
February 5, 2008
since IMFP2006
Rick Field – Florida/CDF/CMS
Page 27
Heavy Quark Production at the Tevatron
with 1 fb-1  Total inelastic stot ~ 100 mb which is
103-104 larger than the cross section for
~1.4 x 1014
~1 x 1011
~6 x 106
~6 x 105
~14,000
~5,000
D-meson or a B-meson.
 However there are lots of heavy quark
events in 1 fb-1!
 Want to study the production of
charmed mesons and baryons: D+, D0,
Ds , lc , cc , Xc, etc.
 Want to studey the production of
B-mesons and baryons: Bu , Bd , Bs , Bc ,
lb , Xb, etc.
 Two Heavy Quark Triggers at CDF:
• For semileptonic decays we trigger on
m and e.
• For hadronic decays we trigger on one
or more displaced tracks (i.e. large
impact parameter).
CDF-SVT
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 28
B-Baryon Observations (CDF)
since IMFP2006
The Tevatron is excellent at
producing particles containing
and c quarks
(Bu, Bd, Bs, Bc, Sb, Xb,b)
b
Xb
Sb
bc
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 29
Top Decay Channels




mt>mW+mb so dominant decay tWb.
The top decays before it hadronizes.
B(W  qq) ~ 67%.
B(W  l) ~ 11% l = e, m, t.
dilepton
lepton + jets
all hadronic
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
BR
~5%
~30%
~65%
background
low
moderate
high
Page 30
Dilepton Channel (CDF)
Selection:
•
•
•
•
•
2 leptons ET > 20 GeV with opposite sign. Backgrounds:
• Physics: Drell-Yan, WW/WZ/ZZ, Z
>=2 jets ET > 15 GeV.
 tt
Missing ET > 25 GeV (and away from any jet).
• Instrumental: fake lepton
HT=pTlep+ETjet+MET > 200 GeV.
Z rejection.
since IMFP2006
IMFP2006
84 events
65 events
20 events
background
s(tt)== 6.16
8.3 ±±1.5
(stat)
±±
1.00.72
(syst)
+ 0.5
(lumi)
pb pb
s(tt)
1.05
(stat)
(syst)
+ 0.37
(lumi)
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 31
Lepton+Jets Channel (CDF)
 Require b-jet to be tagged for
discrimination.
b-Tagging
1 b tag
IMFP2006
~70 events
HT>200GeV
Tagging efficiency for b jets~50%
for c jets~10%
for light q jets < 0.1%
2 b tags
~180 events
~150 events ~45 events
Small
background!
2.0
s(tt)
s(tt)== 8.2
8.8±±0.6
0.5
0.8(stat)
(stat)±±1.1
0.8
1.2(syst)
(sys)
(sys)±±
pb
0.5
0.5(lum)
(lum)
pb
s (tt ) pb
8.81.2
(stat)
1.1
1.3 (syst)pb
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 32
Tevatron Top-Pair Cross Section
since IMFP2006
CDF Run 2 Preliminary
Theory
0.7
s (tt )  6.70.9
pb
Bonciani et al., Nucl. Phys. B529, 424 (1998)
Kidonakis and Vogt, Phys. Rev. D68, 114014 (2003)
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 33
Top Quark Mass
since IMFP2006
Leptons+Jets
Dilepton Channel
Channel
Mt=170.4 ± 3.1(stat) ± 3.0(sys)GeV/c2
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 34
Top Cross-Section vs Mass
Tevatron Summer 2005
CDF Winter 2006
CDF combined
Cacciari, Mangano, et al., hep-ph/0303085
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 35
Constraining the Higgs Mass
 Top quark mass is a fundamental
parameter of SM.
 Radiative corrections to SM
predictions dominated by top
mass.
 Top mass together with W mass
places a constraint on Higgs
mass!
Tevatron Run I + LEP2
Summer 05
114 GeV Higgs very interesting for
the Tevatron!
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 36
Other Sources of Top Quarks
Strongly Produced tt Pairs
 Dominant production mode
sNLO+NLL = 6.7  1.2 pb
 Relatively clean signature
 Discovery in 1995
g
~15%
g
ElectroWeak Production: Single Top
 Larger background
 Smaller cross section s ≈ 2 pb
 Not yet observed!
IMFP2008 - Day 2
February 5, 2008


Rick Field – Florida/CDF/CMS
q
~85%
t
t
q


Page 38
Single Top Production
s-channel
qq  W*  tb
tW associated production
t-channel
bg  tW
qb  q' t
(mtop=175 GeV/c2)
s-channel
t-channel
Associated tW
Tevatron sNLO
0.88  0.11 pb
1.98  0.25 pb
~ 0.1 pb
LHC sNLO
10.6  1.1 pb
247  25 pb
62+17 -4 pb
CDF
< 18 pb
< 13 pb
D0
< 17 pb
< 22 pb
Run I
95% C.L.
< 14 pb
B.W. Harris et al.:Phys.Rev.D66,054024
Z.Sullivan Phys.Rev.D70:114012
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Combine
(s+t)
T.Tait: hep-ph/9909352
Belyaev,Boos: hep-ph/0003260
Page 39
Single Top at the Tevatron
IMFP2006
95% C.L. limits on single top cross-section
Channel
CDF (696 pb-1)
DØ (370 pb-1)
Combined
3.4 pb (2.9 pb)
s-channel
3.2 pb (0.9 pb)
5.0 pb
t-channel
3.1 pb (2 pb)
4.4 pb
 The current CDF and DØ analyses not only provide drastically improved
limits on the single top cross-section, but set all necessary tools and
methods toward a possible discovery with a larger data sample!
 Both collaborations are aggressively working on improving the results!
Theory!
Single Top Discovery is Possible in Run 2 !!!!
- R. Field (IMFP2006)
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 40
Single Top Production
since IMFP2006
Single Top
Signal!
DØ Combination
3.6s!
3.4s!
Expected sensitivity: 2.1s
ss+t= 4.9 ±1.4 pb
ss= 1.0, st =4.0 pb
PRL 98 18102 (2007)
IMFP2008 - Day 2
February 5, 2008
First direct measurement of Vtb
0.68 <|Vtb|< 1 @ 95%CL or
|Vtb| = 1.3 ± 0.2
Rick Field – Florida/CDF/CMS
Page 41
Single Top Production
since IMFP2006
3.1s!
ss+t= 2.7 ± 1.2 pb
ss= 1.1, st =1.3 pb
Expected sensitivity: 2.9s
Observed significance: 2.7s
IMFP2008 - Day 2
February 5, 2008
ss+t= 3.0 ± 1.2 pb
ss= 1.1, st =1.9 pb
Expected sensitivity: 3.0s
Rick Field – Florida/CDF/CMS
Page 42
Measurement of |Vtb| (CDF)
 Using the Matrix Element cross section
measurement, CDF determines |Vtb|
assuming |Vtb| >> |Vts|, |Vtd|!
CDF Run II Preliminary L=1.5 fb-1
s-channel
t-channel
|Vtb|= 1.02 ± 0.18 (exp) ± 0.07(thy)
DØ |Vtb|>0.68, |Vtb| = 1.3 ±0.2
IMFP2008 - Day 2
February 5, 2008
Z. Sullivan, Phys.Rev. D70 (2004) 114012
Rick Field – Florida/CDF/CMS
Page 43
Single Top Candidate Event
 t-channel single top production has a
kinematic peculiarity.
 Distinct asymmetry in lepton charge Q
times the pseudo-rapidity of the untagged
jet! Central Electron Candidate
Charge:
u -1, Eta=-0.72d MET=41.6 GeV
t-channel
single top!
EPD > 0.9
Jet1: Et=46.7 GeV Eta=-0.6 b-tag=1
Jet2: Et=16.6 GeV Eta=-2.9 b-tag=0
Q×h = 2.9 (t-channel signature)
EPD=0.95
CDF Run: 211883, Event: 1911511
Jet1
Lepton
Jet2
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 44
Single Top at the Tevatron
since IMFP2006
Single top cross-section measurements!
Channel
Theory
CDF (1.5 fb-1)
DØ (0.9 fb-1)
Combined
2.9 pb
3.0 ± 1.2 pb
4.9 ± 1.4 pb
s-channel
0.9 pb
≈ 1.1 pb
≈ 1.0 pb
t-channel
2.0 pb
≈ 1.9 pb
≈ 4.0 pb
 Single top has (almost) been seen at the Tevatron at the
expected rate!
If you think 3.5s is enough to claim discovery?
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 45
Top-AntiTop Resonances
CDF Run 1
Excess is
reduced!
Phys.Rev.Lett. 85, 2062 (2000)
 CDF observed an intriguing excess of events with top-antitop invariant mass
around 500 GeV!
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 46
Top-AntiTop Resonances
 The excess has disappeared!
since IMFP2006
Excess is
gone!
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 47
Tevatron Measurements
Jets
b-quarks
We are getting very close to
the Higgs and/or new physics!
W
Z
W+g
Single top
Z+g
W+W
tt
W+Z
Z+Z
IMFP2008 - Day 2
February 5, 2008
Rick Field – Florida/CDF/CMS
Page 48