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IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 1
What a Difference the Last 2 YearsWhat a Difference the Last 2 YearsHave Made!Have Made!
Rick FieldUniversity of Florida
(for the CDF & D0 Collaborations)
CDF Run 2
Palacio de Jabalquinto, Baeza, Spain
From IMFP2006 → IMFP2008
Physics at the Tevatron
Jet Physics, Heavy Quarks (b, t)Vector Bosons (, W, Z)
Happy Leap Year Day!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 2
Tevatron PerformanceTevatron Performance
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
IMFP 2008~3.3 fb-1 delivered~2.8 fb-1 recorded
IMFP 2006~1.5 fb-1 delivered~1.2 fb-1 recorded
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
~1.6 fb-
1
Integrated Luminosity per Year
The data collected since IMFP 2006 more than doubled the total data collected in Run 2!
23 tt-pairs/month!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 3
Many New Tevatron Results!Many New Tevatron Results!
Observation of Bs-mixing: Δms = 17.77 ± 0.10 (stat) ± 0.07(sys).
Observation of new baryon states: b and b.
Observation of new charmless: B→hh states. Evidence for Do-Dobar mixing . Precision W mass measurement: Mw = 80.413 GeV (±48 MeV).
Precision Top mass measurement: Mtop = 170.5 (±2.2) GeV.
W-width measurement: 2.032 (±0.071) GeV. WZ discovery (6-sigma): = 5.0 (±1.7) pb. ZZ evidence (3-sigma). Single Top evidence (3-sigma) with 1.5 fb-1: = 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.
Some of the CDF Results since IMFP2006
I cannot possibility cover all the great physics results from theTevatron since IMFP 2006!I will show a few of the results!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 4
In Search of Rare ProcessesIn Search of Rare Processes
~9 orders of magnitude Higgs ED
PR
OD
UC
TIO
N C
RO
SS
SE
CT
ION
(fb
)
1 pb
We are beginning to measure cross-sections ≤ 1 pb!
W’, Z’, T’
We might get lucky!
(pT(jet) > 525 GeV) ≈ 15 fb!
15 fb
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 5
Jets at TevatronJets at Tevatron
Experimental Jets: The study of “real” jets requires a “jet algorithm” and the different algorithms correspond to different observables and give different results!
“Theory Jets”
Next-to-leading order parton level calculation
0, 1, 2, or 3 partons!
“Tevatron Jets”
Experimental Jets: The study of “real” jets requires a good understanding of the calorimeter response!
Experimental Jets: To compare with NLO parton level (and measure structure functions) requires a good understanding of the “underlying event”!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 6
Jet CorrectionsJet CorrectionsCalorimeter Jets:
We measure “jets” at the “hadron level” in the calorimeter. We certainly want to correct the “jets” for the detector resolution and
effieciency. Also, we must correct the “jets” for “pile-up”. Must correct what we measure back to the true “particle level” jets!
Proton AntiProton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
Particle Level Jets: Do we want to make further model dependent corrections? Do we want to try and subtract the “underlying event” from the
“particle level” jets. This cannot really be done, but if you trust the Monte-Carlo
models modeling of the “underlying event” you can try and do it by using the Monte-Carlo models (use PYTHIA Tune A).
Parton Level Jets: Do we want to use our data to try and extrapolate back to the parton
level? This also cannot really be done, but again if you trust the Monte-
Carlo models you can try and do it by using the Monte-Carlo models.
The “underlying event” consists of hard initial & final-state radiation
plus the “beam-beam remnants” and possible multiple parton interactions.
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 7
Inclusive Jet Cross Section (CDF)Inclusive Jet Cross Section (CDF)
Run I CDF Inclusive Jet Data(Statistical Errors Only)JetClu RCONE=0.7 0.1<||<0.7R=F=ET /2 RSEP=1.3
CTEQ4M PDFsCTEQ4HJ PDFs
Run 1 showed a possible excess at large jet ET (see below).
This resulted in new PDF’s with more gluons at large x.
The Run 2 data are consistent with the new structure functions (CTEQ6.1M).
CTEQ4M
CTEQ4HJ
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 8
Inclusive Jet Cross Section (CDF)Inclusive Jet Cross Section (CDF)
IMFP2006
MidPoint Cone Algorithm (R = 0.7, fmerge = 0.75)
Data corrected to the hadron level L = 1.04 fb-1
0.1 < |yjet| < 0.7
Compared with NLO QCD
Sensitive to UE + hadronization effects for PT < 200 GeV/c!
today 1.13 fb-1
(pT > 525 GeV) ≈ 15 fb!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 9
KKTT Algorithm Algorithm
Proton AntiProton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
kT Algorithm: Cluster together calorimeter towers by their kT proximity. Infrared and collinear safe at all orders of pQCD. No splitting and merging. No ad hoc Rsep parameter necessary to compare with parton level. Every parton, particle, or tower is assigned to a “jet”. No biases from seed towers. Favored algorithm in e+e- annihilations!
For each precluster, calculate 2
,iTi pd
For each pair of preculsters, calculate
2
222
,2
,
)()(),min(
D
yyppd jiji
jTiTij
Find the minimum of all di and dij.
Move i to list of jets
no
yes
Begin
End
Minumum is dij?
Any Preclusters
left?
no
Merge i and j
yes
KT Algorithm
Only towers with ET > 0.5 GeV are shown
Raw Jet ET = 533 GeVRaw Jet ET = 618 GeV
Will the KT algorithm be effective in the collider
environment where there is an “underlying event”?
CDF Run 2
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 10
KKTT Inclusive Jet Cross Section (CDF) Inclusive Jet Cross Section (CDF)
KT Algorithm (D = 0.7)
Data corrected to the hadron level L = 385 pb-1
0.1 < |yjet| < 0.7
Compared with NLO QCD.
IMFP2006today 1.0 fb-1
Sensitive to UE + hadronization effects for PT < 200 GeV/c!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 11
from Run I
High x Gluon PDFHigh x Gluon PDF Forward jets measurements put
constraints on the high x gluon distribution!
Uncertainty on gluon PDF (from CTEQ6)
x
Big uncertainty for high-x gluon PDF!
high x low x
Forward Jets
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 12
KKTT Forward Jet Cross Section (CDF) Forward Jet Cross Section (CDF)KT Algorithm (D = 0.7).Data corrected to the hadron
level.L = 385 pb-1.
Five rapidity regions: |yjet| < 0.1 0.1 < |yjet| < 0.7 0.7 < |yjet| < 1.1 1.1 < |yjet| < 1.6 1.6 < |yjet| < 2.1
Compared with NLO QCD
IMFP2006
today 1.0 fb-1
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 13
Forward Jet Cross Section (CDF)Forward Jet Cross Section (CDF)MidPoint Cone Algorithm
(R = 0.7, fmerge = 0.75)Data corrected to the
hadron levelL = 1.13 pb-1.
Five rapidity regions: |yjet| < 0.1 0.1 < |yjet| < 0.7 0.7 < |yjet| < 1.1 1.1 < |yjet| < 1.6 1.6 < |yjet| < 2.1
Compared with NLO QCD
1.0 fb-1
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 14
DiJet Cross Section (CDF)DiJet Cross Section (CDF) MidPoint Cone Algorithm (R
= 0.7, fmerge = 0.75)
Data corrected to the hadron level L = 1.13 fb-1
|yjet1,2| < 1.0
Compared with NLO QCD
since IMFP2006
Sensitive to UE + hadronization effects!
CDF Run II Preliminary
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 15
Inclusive Jet versus DiJet (CDF)Inclusive Jet versus DiJet (CDF)
MidPoint Cone Algorithm (R = 0.7, fmerge = 0.75)
CTEQ6.1M = PT/2
MidPoint Cone Algorithm (R = 0.7, fmerge = 0.75)
CTEQ6.1M = mean(PT1,PT2)
Inclusive Jet (CDF) DiJet (CDF)
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 16
CDF DiJet Event: M(jj) CDF DiJet Event: M(jj) ≈ 1.4 TeV≈ 1.4 TeV
ETjet1 = 666 GeV ET
jet2 = 633 GeV Esum = 1,299 GeV M(jj) = 1,364 GeV
M(jj)/Ecm ≈ 70%!!
Exclusive p+p → p+p+e++e- (16 events) = 1.6 ± 0.3 pb
CDF Run II
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 17
-1 +1
2
0
Leading Jet
Toward Region
Transverse Region
Transverse Region
Away Region
Away Region
Jet #1 Direction
“Transverse” “Transverse”
“Toward”
“Away”
“Toward-Side” Jet
“Away-Side” Jet
““Towards”, “Away”, “Transverse”Towards”, “Away”, “Transverse”
Look at correlations in the azimuthal angle relative to the leading charged particle jet (|| < 1) or the leading calorimeter jet (|| < 2).
Define || < 60o as “Toward”, 60o < | < 120o as “Transverse ”, and || > 120o as “Away”. Each of the three regions have area = 2×120o = 4/3.
Jet #1 Direction
“Toward”
“Transverse” “Transverse”
“Away”
Correlations relative to the leading jetCharged particles pT > 0.5 GeV/c || < 1Calorimeter towers ET > 0.1 GeV || < 1“Transverse” region is
very sensitive to the “underlying event”!
Look at the charged particle density, the
charged PTsum density and the ETsum density in
all 3 regions!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 18
Jet #1 Direction
“Overall”
“Leading Jet”
Overall Totals (|Overall Totals (|| < 1)| < 1)
Data at 1.96 TeV on the overall number of charged particles (pT > 0.5 GeV/c, || < 1) and the overall scalar pT sum of charged particles (pT > 0.5 GeV/c, || < 1) and the overall scalar ET sum of all particles (|| < 1) for “leading jet” events as a function of the leading jet pT. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A at the particle level (i.e. generator level)..
Overall Totals versus PT(jet#1)
1
10
100
1000
0 50 100 150 200 250 300 350 400
PT(jet#1) (GeV/c)
Av
era
ge
CDF Run 2 Preliminarydata corrected
pyA generator level
"Leading Jet"MidPoint R=0.7 |(jet#1)|<2
Charged Particles (||<1.0, PT>0.5 GeV/c)
Stable Particles (||<1.0, all PT)
ETsum (GeV)
PTsum (GeV/c)
Nchg
Nchg = 30
PTsum = 190 GeV/c
ETsum = 330 GeV
ETsum = 775 GeV!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 19
Jet #1 Direction
“Toward”
“Transverse” “Transverse”
“Away”
“Leading Jet”
““Towards”, “Away”, “Transverse”Towards”, “Away”, “Transverse”
Data at 1.96 TeV on the density of charged particles, dN/dd, with pT > 0.5 GeV/c and || < 1 for “leading jet” events as a function of the leading jet pT for the “toward”, “away”, and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A at the particle level (i.e. generator level).
Charged Particle Density: dN/dd
0
1
2
3
4
5
0 50 100 150 200 250 300 350 400
PT(jet#1) (GeV/c)
Ave
rag
e C
har
ged
Den
sity
CDF Run 2 Preliminarydata corrected
pyA generator level
"Leading Jet"MidPoint R=0.7 |(jet#1)|<2
Charged Particles (||<1.0, PT>0.5 GeV/c)
"Away"
"Toward"
"Transverse"
Data at 1.96 TeV on the charged particle scalar pT sum density, dPT/dd, with pT > 0.5 GeV/c and || < 1 for “leading jet” events as a function of the leading jet pT for the “toward”, “away”, and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A at the particle level (i.e. generator level).
Data at 1.96 TeV on the particle scalar ET sum density, dET/dd, for || < 1 for “leading jet” events as a function of the leading jet pT for the “toward”, “away”, and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A at the particle level (i.e. generator level).
Factor of ~4.5
Charged PTsum Density: dPT/dd
0.1
1.0
10.0
100.0
0 50 100 150 200 250 300 350 400
PT(jet#1) (GeV/c)
Ch
arg
ed P
Tsu
m D
ensi
ty (
GeV
/c)
CDF Run 2 Preliminarydata corrected
pyA generator level
"Leading Jet"MidPoint R=0.7 |(jet#1)|<2
Charged Particles (||<1.0, PT>0.5 GeV/c)
"Toward""Away"
"Transverse"
Factor of ~16
ETsum Density: dET/dd
0.1
1.0
10.0
100.0
0 50 100 150 200 250 300 350 400
PT(jet#1) (GeV/c)
ET
sum
Den
sity
(G
eV)
CDF Run 2 Preliminarydata corrected
pyA generator level
"Leading Jet"MidPoint R=0.7 |(jet#1)|<2
Stable Particles (||<1.0, all PT)
"Toward"
"Away"
"Transverse"
Factor of ~13
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 20
“Leading Jet”
The Leading Jet MassThe Leading Jet Mass
Data at 1.96 TeV on the leading jet invariant mass for “leading jet” events as a function of the leading jet pT. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level).
Shows the Data - Theory for the leading jet invariant mass for “leading jet” events as a function of the leading jet pT for PYTHIA Tune A and HERWIG (without MPI).
Leading Jet Invariant Mass
0
10
20
30
40
50
60
70
0 50 100 150 200 250 300 350 400
PT(jet#1) (GeV/c)
Jet
Mas
s (G
eV)
"Leading Jet"MidPoint R=0.7 |(jet#1)|<2
CDF Run 2 Preliminarydata corrected
generator level theory
PY Tune A
HW
Leading Jet Invariant Mass
-4.0
0.0
4.0
8.0
12.0
0 50 100 150 200 250 300 350 400
PT(jet#1 uncorrected) (GeV/c)
Dat
a -
Th
eory
(G
eV)
CDF Run 2 Preliminarydata corrected
generator level theory
"Leading Jet"MidPoint R=0.7 |(jet#1)|<2
HW PY Tune A
Off by ~2 GeV
Jet #1 Direction
“Toward”
“Transverse” “Transverse”
“Away”
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 21
bb DiJet Cross Section (CDF)bb DiJet Cross Section (CDF)
b-quark tag based on displaced vertices. Secondary vertex mass discriminates flavor.
Require two secondary vertex tagged b-jets within |y|< 1.2 and study the two b-jets (Mjj, jj, etc.).
Collision point
≈ 85% purity!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 22
The Sources of Heavy QuarksThe Sources of Heavy Quarks
We do not observe c or b quarks directly. We measure D-mesons (which contain a c-quark) or we measure B-mesons (which contain a b-quark) or we measure c-jets (jets containing a D-meson) or we measure b-jets (jets containing a B-meson).
Proton AntiProton
“Flavor Creation” Q-quark
Q-quark
Underlying Event Underlying Event
Initial-State Radiation
Leading Order Matrix ElementsLeading-Log Order
QCD Monte-Carlo Model (LLMC)
Dbjpip FbkijdGGBd )()(
(structure functions) × (matrix elements) × (Fragmentation)
+ (initial and final-state radiation: LLA)
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 23
Other Sources of Heavy QuarksOther Sources of Heavy Quarks
In the leading-log order Monte-Carlo models (LLMC) the separation into “flavor creation”, “flavor excitation”, and “gluon splitting” is unambiguous, however at next to leading order the same amplitudes contribute to all three processes!
Next to Leading Order Matrix Elements
Proton AntiProton
“Flavor Excitation” Q-quark
gluon, quark, or antiquark
Underlying Event Underlying Event
Initial-State Radiation
Q-quark
“Flavor Excitation” (LLMC) corresponds to the scattering of a b-quark (or bbar-quark) out of the initial-state into the final-state by a gluon or by a light quark or antiquark.
Proton AntiProton
“Gluon Splitting”
Q-quark
Underlying Event Underlying Event
Initial-State Radiation
Q-quark
“Gluon-Splitting” (LLMC) is where a b-bbar pair is created within a parton shower or during the the fragmentation process of a gluon or a light quark or antiquark. Here the QCD hard 2-to-2 subprocess involves only gluons and light quarks and antiquarks.
g
g
g
Q
Q Amp (FC)
g
g
g
Q
Q
Amp (FE)
g
g
g
Q
Q
Amp (GS)
Amp(gg→QQg) = + +(gg→QQg) =
2and there are interference terms!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 24
bb DiJet Cross Section (CDF)bb DiJet Cross Section (CDF) ET(b-jet#1) > 35 GeV, ET(b-jet#2) > 32
GeV, |(b-jets)| < 1.2.
Preliminary CDF Results:
bb = 34.5 1.8 10.5 nb
QCD Monte-Carlo Predictions:
PYTHIA Tune A CTEQ5L
38.7 ± 0.6 nb
HERWIG CTEQ5L 21.5 ± 0.7 nb
MC@NLO 28.5 ± 0.6 nb
MC@NLO + Jimmy 35.7 ± 2.0 nb
Differential Cross Section as a function of the b-bbar DiJet invariant mass!
Proton AntiProton
“Flavor Creation”
b-quark
b-quark
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
Adding multiple parton interactions (i.e. JIMMY) to enhance the “underlying event” increases the b-bbar jet cross section!
JIMMY: MPIJ. M. Butterworth
J. R. ForshawM. H. Seymour
JIMMYRuns with HERWIG and adds multiple parton interactions!
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 25
bb DiJet Cross Section (CDF)bb DiJet Cross Section (CDF)
ET(b-jet#1) > 35 GeV, ET(b-jet#2) > 32 GeV, |(b-jets)| < 1.2.
Sensitive to the “underlying event”!
Preliminary CDF Results:
bb = 5664 168 1270 pb
QCD Monte-Carlo Predictions:
PYTHIA Tune A CTEQ5L
5136 ± 52 pb
HERWIG CTEQ5L+Jimmy
5296 ± 98 pb
MC@NLO+Jimmy 5421 ± 105 nb
Proton AntiProton
“Flavor Creation” b-quark
b-quark
Underlying Event Underlying Event
Initial-State Radiation
SystematicUncertainty
Predominately Flavor creation!
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 26
bb DiJet bb DiJet Distribution (CDF) Distribution (CDF)
It takes NLO + “underlying event” to get it right!
Proton AntiProton
“Flavor Creation” b-quark
b-quark
Underlying Event Underlying Event
Initial-State Radiation
b-jet direction
“Toward”
“Away”
bbar-jet
Large (i.e. b-jets are “back-to-back”) is predominately “flavor creation”.
Small (i.e. b-jets are near each other) is predominately “flavor excitation” and “gluon splitting”.
Proton AntiProton
“Gluon Splitting”
Q-quark
Underlying Event Underlying Event
Initial-State Radiation
Q-quark
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 27
Z + b-Jet Production (CDFZ + b-Jet Production (CDF)) Important background for new physics!
)(0033.0)(0078.00237.0][
][
14.032.096.0)(
syststatjetZ
bjetZR
pbbjetZ
Extract fraction of b-tagged jets from secondary vertex mass distribution: NO assumption on the charm content.
L = 335 pb-1
Leptonic decays for the Z. Z associated with jets. CDF: JETCLU, D0: R = 0.7, |jet| < 1.5, ET >20 GeV
Look for tagged jets in Z events.
IMFP2006
Observable CDF Data PYTHIA Tune A MCFM NLO (+UE)
(Z+b-jet) 0.94±0.15±0.15 pb -- 0.51 (0.56) pb
(Z+b-jet)/(Z) 0.369±0.057±0.055 % 0.35% 0.21 (0.23) %
(Z+b-jet)/(Z+jet) 2.35±0.36±0.45 % 2.18% 1.88 (1.77) %
today 1.5 fb-1
Sensitive to the “underlying event”!
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 28
Z-boson Cross Section (CDF)Z-boson Cross Section (CDF)
Impressive agreement between experiment and NNLO theory (Stirling, van Neerven)!
CDF (pb) NNLO (pb)
(Z→e+e-) 254.93.3(stat)4.6(sys)15.2(lum) 252.35.0
L = 72 pb-1
QCDDrell-Yan
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 29
Z-boson Cross Section (CDF)Z-boson Cross Section (CDF)
Impressive agreement between experiment and NNLO theory (Stirling, van Neerven)!
CDF (pb) NNLO (pb)
(Z→+-) 261.22.7(stat)6.9(sys)15.1(lum) 252.35.0
L = 337 pb-1IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 30
Z-Boson Rapidity DistributionZ-Boson Rapidity Distribution Measure d/dy for 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!
Zcc Zcp Zpp
CDF ZCC ZCP ZPP
Events 28,097 46,676 16,589
1.1fb-1 91,362 events 66 < MZ < 116 GeV
since IMFP2006
Plug-Plug electrons!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 31
Z-Boson Rapidity DistributionZ-Boson Rapidity Distribution CDF measured d/dy for Z/*
compared with an NL0 calculation using CTEQ6.1M PDF.
The NLO theory is scaled to the measured (Z)!
No PDF or luminosity uncertainties included.
since IMFP2006
CDF (pb) NNLO (pb)
(Z→e+e-) 263.3±0.9(stat)±3.8(sys) 252.35.0
NLO + CTEQ6.1 PDF NLO + MRST PDFNLL0 + NNL0 MRST PDF
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 32
The ZThe Z→→ Cross Section (CDF) Cross Section (CDF)Signalcone
Isolationcone
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.
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.
Channel for Z→ττ: electron + isolated track• One decays to an electron: τ→e+X (ET(e) > 10 GeV) .
• One decays to hadrons: τ → h+X (pT > 15GeV/c).
Remove Drell-Yan e+e- and apply event topology cuts for non-Z background.
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 33
The ZThe Z→→ Cross Section (CDF) 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 signsame sign,
opposite sign
CDF (pb) NNLO (pb)
(Z→+-) 26520(stat)21(sys)15(lum) 252.35.0264 ± 23 (stat) ± 14 (sys) ± 15 (lum)
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 34
Higgs Higgs → → Search (CDF) Search (CDF)
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.
140 GeV Higgs Signal!
events
1 event
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 35
Higgs Higgs → → Search (CDF) Search (CDF)events events
No Significant Excess of events above SM background is observed!
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 36
W-bosonW-boson Cross Section (CDF) Cross Section (CDF)
(W) L CDF (pb) NNLO(pb)
Central
electrons72 pb-1 277510(stat)53(sys)167(lum) 268754
Forward
electrons223 pb-1 281513(stat)94(sys)169(lum) 268754
CDF NNLO
(W)/(Z) 10.920.15(stat)0.14(sys)
10.690.08
Extend electron coverage to the forward region (1.2 < || < 2.8)!
48,144 W candidates ~4.5% background48,144 W candidates ~4.5% background overall efficiency of signal ~7% overall efficiency of signal ~7%
W Acceptance
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 37
W-Boson Mass MeasurementW-Boson Mass MeasurementThe 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
since IMFP2006
Single most precise measurement to date!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 38
W-Boson Width MeasurementW-Boson Width MeasurementModel 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.
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 39
W Production Charge AsymmetryW Production Charge Asymmetry
WW
WWW dyddyd
dyddydyA
//
//)(
d
uu p
u
udp
W+
e+
e
xG
(x,Q
2)
x
u
d
W- W+
yprotonantiproton
10-3 10-2 10-1 1
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!
Q2 = 100 GeV2
MRST2004NLO
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 40
W Production Charge AsymmetryW 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!
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 cross-section, (yW).
The process is iterated since (yW) depends on the asymmetry.
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 41
W + W + Cross Sections (CDF) Cross Sections (CDF)
CDF (pb) NLO (pb)
(W+)*BR(W->l) 19.71.7(stat)2.0(sys)1.1(lum) 19.31.4
ET() > 7 GeVR(l) > 0.7
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 42
W + W + Cross Sections (CDF) Cross Sections (CDF)
CDF (pb) NLO (pb)
(W+)*BR(W->l) 19.71.7(stat)2.0(sys)1.1(lum) 19.31.4
ET() > 7 GeVR(l) > 0.7
18.03±0.65(stat)±2.55(sys) ±1.05(lum)
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 43
Z + Z + Cross Sections (CDF) Cross Sections (CDF)
CDF (pb) NLO (pb)
(Z+)*BR(Z->ll) 5.30.6(stat)0.3(sys)0.3(lum) 5.40.3
ET() > 7 GeVR(l) > 0.7
Note: (W)/(Z) ≈ 4
while (W)/(Z) ≈ 11
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 44
Z + Z + Cross Sections (CDF) Cross Sections (CDF)
CDF (pb) NLO (pb)
(Z+)*BR(Z->ee) 4.90.3(stat)0.3(sys)0.3(lum) 4.70.4
ET() > 7 GeVR(l) > 0.7
Mee > 40 GeV/c2
390 events
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 45
The W+W Cross-SectionThe W+W Cross-Section
pb-1 CDF (pb) NLO (pb)
(WW) CDF 184 14.6+5.8(stat)-5.1(stat)1.8(sys)0.9(lum) 12.40.8
(WW) DØ 240 13.8+4.3(stat)-3.8(stat)1.2(sys)0.9(lum) 12.40.8
Campbell & Ellis 1999
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 46
The W+W Cross-Section (CDF)The W+W Cross-Section (CDF)
L CDF (pb) NLO (pb)
(WW) 825 pb-1 13.72.3(stat)1.6(sys)1.2(lum) 12.40.8
WW→dileptons + MET Two leptons pT > 20 GeV/c.
Z veto. MET > 20 GeV. Zero jets with ET>15 GeV
and ||<2.5.Observe 95 events with
37.2 background!
L = 825 pb-1 IMFP2006
Missing ET! Lepton-Pair Mass! ET Sum!
We are beginning to study the details ofDi-Boson production at the Tevatron!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 47
WW+WZ Cross-SectionWW+WZ Cross-Section
CDF (pb) NLO (pb)
(WW+WZ)×BR(lvjj) 1.47 ± 0.77(stat) ± 0.38(sys) 2.1 ± 0.2 pb
NLO TheoryσWW × Br(W→l, W→jj) = 12.4 pb × 0.146 = 1.81 pbσWZ × Br(W→l, Z→jj) = 3.96 pb × 0.07 = 0.28 pb
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 48
The Z+W, Z+Z Cross Sections The Z+W, Z+Z Cross Sections
W+Z, Z+Z Limit (pb) NLO (pb)
CDF (194 pb-1) sum < 15.2 (95% CL) 5.00.4
DØ (300 pb-1) W+Z < 13.3 (95% CL) 3.70.1
Upper Limits
CDF (825 pb-1) W+Z < 6.34 (95% CL) 3.70.1
W+Z → trileptons + METObserve 2 events with a background of 0.9±0.2!
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 49
The W+Z Cross SectionThe W+Z Cross SectionStrategy Search for events with 3 leptons and missing
energy. Small cross-section but very clean signal. Anomalous cross-section sensitive to non SM
contributions.
L CDF (pb) NLO (pb)
(W+Z) 1.9 fb-1 4.3±1.3(stat) ±0.2(sys) ±0.3(lum) 3.70.3
3.0 σ significance!
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 50
The Z+Z Cross SectionThe Z+Z Cross SectionStrategy: Search for events with either 4 leptons or
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.
L CDF (pb) NLO (pb)
(Z+Z) 1.9 fb-1 0.75+0.71-0.54 1.4±0.1
3.0 σ significance!
ZZ decaying into 4 leptons
since IMFP2006
ZZ decaying into 2 leptons + MET
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 51
Higgs Higgs → W+W→ W+W We are within a factor of two of
the standard model Higgs (160 GeV) → WW!
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 52
Heavy Quark Production at the TevatronHeavy Quark Production at the Tevatron
Total inelastic tot ~ 100 mb which is 103-104 larger than the cross section for 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 , c , c , c, etc.
Want to studey the production of B-mesons and baryons: Bu , Bd , Bs , Bc , b , b, etc.
Two Heavy Quark Triggers at CDF:
• For semileptonic decays we trigger on and e.
• For hadronic decays we trigger on one or more displaced tracks (i.e. large impact parameter).
with 1 fb-1
~1.4 x 1014
~1 x 1011
~6 x 106
~6 x 105
~14,000 ~5,000
CDF-SVT
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 53
B-Baryon Observations (CDF)B-Baryon Observations (CDF)
b
bc
b
The Tevatron is excellent at producing particles containing
b and c quarks(Bu, Bd, Bs, Bc, b, b,b)
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 54
Top Decay ChannelsTop Decay Channels mt>mW+mb so dominant decay tWb.
The top decays before it hadronizes. B(W qq) ~ 67%. B(W l) ~ 11% l = e,
BR backgrounddilepton ~5% lowlepton + jets ~30% moderateall hadronic ~65% high
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 55
Dilepton Channel (CDF)Dilepton Channel (CDF)Backgrounds:
• Physics: Drell-Yan, WW/WZ/ZZ, Z
• Instrumental: fake lepton
Selection:• 2 leptons ET > 20 GeV with opposite sign.• >=2 jets ET > 15 GeV.• Missing ET > 25 GeV (and away from any jet).• HT=pTlep+ETjet+MET > 200 GeV.• Z rejection.
(tt) = 8.3 ± 1.5 (stat) ± 1.0 (syst) + 0.5 (lumi) pb
65 events
20 eventsbackground
IMFP2006
84 events
since IMFP2006
(tt) = 6.16 ± 1.05 (stat) ± 0.72 (syst) + 0.37 (lumi) pb
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 56
Lepton+Jets Channel (CDF)Lepton+Jets Channel (CDF)
HT>200GeV
(tt ) 8.8 1.11.2 (stat) 1.3
2.0 (syst)pb
b-Taggingb-TaggingRequire b-jet to be tagged for
discrimination.
Tagging efficiency for b jets~50% for c jets~10%
for light q jets < 0.1%
~150 events
(tt) = 8.2 ± 0.6 (stat) ± 1.1 (syst) pb
~45 events
IMFP2006
~180 events
1 b tag
Small background!
~70 events2 b tags
(tt) = 8.2 ± 0.5 (stat) ± 0.8 (sys) ± 0.5 (lum) pb(tt) = 8.8 ± 0.8 (stat) ± 1.2 (sys) ± 0.5 (lum) pb
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 57
Tevatron Top-Pair Cross SectionTevatron Top-Pair Cross Section
Bonciani et al., Nucl. Phys. B529, 424 (1998)Kidonakis and Vogt, Phys. Rev. D68, 114014 (2003)
CDF Run 2 Preliminary
(tt ) 6.7 0.90.7 pb
Theory
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 58
Top Quark MassTop Quark Mass
Dilepton Channel
since IMFP2006
Mt=170.4 ± 3.1(stat) ± 3.0(sys)GeV/c2
Leptons+Jets Channel
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 59
Top Cross-Section vs MassTop Cross-Section vs Mass
Tevatron Summer 2005 CDF Winter 2006
Cacciari, Mangano, et al., hep-ph/0303085
CDF combined
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 60
Constraining the Higgs MassConstraining 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!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 62
Other Sources of Top QuarksOther Sources of Top Quarks
q
q
t
t
~85%
g
g
Strongly Produced tt PairsStrongly Produced tt PairsDominant production mode
NLO+NLL = 6.7 1.2 pb
Relatively clean signatureDiscovery in 1995
ElectroWeak Production: ElectroWeak Production: Single TopSingle Top
Larger backgroundSmaller cross section ≈ 2 pbNot yet observed!
~15%
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 63
Single Top ProductionSingle Top ProductionbtWqq * tqqb ' tWbg
s-channel t-channel Associated tW
Combine
(s+t)
Tevatron NLO 0.88 0.11 pb 1.98 0.25 pb ~ 0.1 pb
LHC NLO 10.6 1.1 pb 247 25 pb 62+17 -4 pb
CDF < 18 pb < 13 pb < 14 pb
D0 < 17 pb < 22 pb
B.W. Harris et al.:Phys.Rev.D66,054024 T.Tait: hep-ph/9909352
Z.Sullivan Phys.Rev.D70:114012 Belyaev,Boos: hep-ph/0003260
Run I
95% C.L.
(mtop=175 GeV/c2)
s-channel t-channel tW associated production
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 64
Single Top at the TevatronSingle Top at the Tevatron
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!
95% C.L. limits on single top cross-section
Single Top Discovery is Possible in Run 2 !!!!Single Top Discovery is Possible in Run 2 !!!!- R. Field (IMFP2006)- R. Field (IMFP2006)
ChannelChannel CDF (696 pbCDF (696 pb-1-1)) DØ (370 pbDØ (370 pb-1-1))
Combined 3.4 pb
s-channel 3.2 pb 5.0 pb
t-channel 3.1 pb 4.4 pb(2 pb)(2 pb)
(0.9 pb)(0.9 pb)
(2.9 pb)(2.9 pb)
Theory!
IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 65
Single Top ProductionSingle Top Production
First direct measurement of Vtb
0.68 <|Vtb|< 1 @ 95%CL or
|Vtb| = 1.3 ± 0.2
First direct measurement of Vtb
0.68 <|Vtb|< 1 @ 95%CL or
|Vtb| = 1.3 ± 0.2
s+t= 4.9 ±1.4 pb
s= 1.0, t =4.0 pb
s+t= 4.9 ±1.4 pb
s= 1.0, t =4.0 pb
Expected sensitivity: 2.1
PRL 98 18102 (2007)
Single Top Signal!
since IMFP2006
3.4!
DØ Combination3.6!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 66
Single Top ProductionSingle Top Production
s+t= 3.0 ± 1.2 pb
s= 1.1, t =1.9 pb
s+t= 3.0 ± 1.2 pb
s= 1.1, t =1.9 pb
Expected sensitivity: 2.9Observed significance: 2.7
Expected sensitivity: 3.0
s+t= 2.7 ± 1.2 pb
s= 1.1, t =1.3 pb
s+t= 2.7 ± 1.2 pb
s= 1.1, t =1.3 pb
3.1!
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 67
Measurement of |VMeasurement of |Vtbtb| (CDF)| (CDF)CDF Run II Preliminary
L=1.5 fb-1
|Vtb|= 1.02 ± 0.18 (exp) ± 0.07(thy)|Vtb|= 1.02 ± 0.18 (exp) ± 0.07(thy)
t-channel
s-channel
Z. Sullivan, Phys.Rev. D70 (2004) 114012DØ |Vtb|>0.68, |Vtb| = 1.3 ±0.2
Using the Matrix Element cross section measurement, CDF determines |Vtb| assuming |Vtb| >> |Vts|, |Vtd|!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 68
u d
Single Top Candidate EventSingle Top Candidate Event
EPD > 0.9EPD > 0.9
t-channel single top production has a kinematic peculiarity.
Distinct asymmetry in lepton charge Q times the pseudo-rapidity of the untagged jet!
Jet1
Jet2
Lepton
CDF Run: 211883, Event: 1911511
Central Electron CandidateCharge: -1, Eta=-0.72 MET=41.6 GeVJet1: Et=46.7 GeV Eta=-0.6 b-tag=1 Jet2: Et=16.6 GeV Eta=-2.9 b-tag=0Q× = 2.9 (t-channel signature)EPD=0.95
t-channelsingle top!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 69
Single Top at the TevatronSingle Top at the Tevatron
Single top has (almost) been seen at the Tevatron at the expected rate!
Single top cross-section measurements!
ChannelChannel TheoryTheory CDF (1.5 fbCDF (1.5 fb-1-1)) DØ (0.9 fbDØ (0.9 fb-1-1))
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
since IMFP2006
If you think 3.5 is enough to claim discovery?
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 70
Top-AntiTop ResonancesTop-AntiTop Resonances
CDF observed an intriguing excess of events with top-antitop invariant mass around 500 GeV!
Phys.Rev.Lett. 85, 2062 (2000)
CDF Run 1
Excess is reduced!
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 71
Top-AntiTop ResonancesTop-AntiTop Resonances The excess has disappeared!
Excess is gone!
since IMFP2006
IFT - University of Florida February 29, 2008
Rick Field – Florida/CDF/CMS Page 72
Tevatron MeasurementsTevatron MeasurementsJets
b-quarks
W
Z
W+
Z+
W+W
tt
W+Z
Z+Z
Single top
We are getting very close to the Higgs and/or new physics!