IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 1
XXXIV International Meeting on XXXIV International Meeting on Fundamental PhysicsFundamental Physics
Rick FieldUniversity of Florida
(for the CDF & D0 Collaborations)
CDF Run 2
Real Colegio Maria Cristina, El Escorial, Spain
From HERA and the TEVATRON
to the LHC
Physics at the Tevatron
2nd LectureHeavy Quark Physics at the Tevatron
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 2
Heavy Quark Physics at the TevatronHeavy Quark Physics at the Tevatron
Charm Production at the Tevatron.
J/ and Bottom Production at the Tevatron.
Top Production at the Tevatron.
uud
Antiproton
uud
proton
Beam-Beam Remnants Beam-Beam Remnants
1.96 TeV
Charm
c-quark
c-quark
J/
J/
b-hadron
b-quark
b-quark
b-jet
b-jet
b-jet
Top Pair
t-quark
t-quark
Single Top
t-quark
b-quark
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 3
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
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Rick Field – Florida/CDF/CMS Page 4
Selecting Heavy Flavor DecaysSelecting Heavy Flavor Decays To select charm and beauty in an hadronic
environment requires:• High resolution tracking
• A way to trigger on the hadronic decays (i.e. a way to trigger on tracks)
CDF
Primary Vertex
Secondary Vertex
Impact Parameter ( ~100m)
Lxy ~ 1 mm
B/D decay
D0 K
The CDF Secondary Vertex Trigger (SVT)•Online (L2) selection of displaced tracks based on Silicon detector hits.
At CDF we have a “Secondary Vertex Trigger” (the SVT).
Collision Point
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 5
Selecting Prompt Charm ProductionSelecting Prompt Charm Production
Separate prompt (i.e. direct) and secondary charm based on their transverse impact parameter distribution.
Direct Charm Meson Fractions:Direct Charm Meson Fractions:
DD00: f: fDD=86.4±0.4±3.5=86.4±0.4±3.5%%
D*D*++: : ffDD=88.1±1.1±3.9%=88.1±1.1±3.9%
DD++: f: fDD=89.1±0.4±2.8%=89.1±0.4±2.8%
DD++ss: f: fDD=77.3±3.8±2.1%=77.3±3.8±2.1%
BD tail
Prompt D Secondary D from B
Promptpeak
D impact parameter
Prompt D-meson decays point back to primary vertex (i.e. the collision point).
Secondary D-meson decays do not point back to the primary vertex.
Most of reconstructed D mesons are prompt!
Collision Point
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 6
Prompt Charm Meson ProductionPrompt Charm Meson Production
Theory calculation from M. Cacciari and P. Nason: Resummed perturbative QCD (FONLL), JHEP 0309,006 (2003). Fragmentation: ALEPH measurement, CTEQ6M PDF.
Charm Meson PT Distributions
bpD
bpD
bpD
bpD
Ts
T
T
T
22.005.075.0)1|Y|GeV,8,(
7.01.03.4)1|Y|GeV,6,(
8.01.02.5)1|Y|GeV,6,*(
5.12.03.13)1|Y|5.5GeV,,( 0
CDF prompt charm cross section result published in PRL (hep-ex/0307080)
Data collected by SVT trigger from 2/2002-3/2002
L = 5.8±0.3 pb-1.
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 7
Comparisons with TheoryComparisons with Theory
NLO calculations compatible within errors? The pT shapes are consistent with the theory for the D mesons,
but the measured cross section are a factor of about ~1.5 higher!
Ratio of Data to Theory
Next step is to study charm-anticharm correlations to learn about the contributions from different
production mechanisms:“flavor creation”
“flavor Excitation”“gluon splitting”
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 8
Bottom Quark Production at the TevatronBottom Quark Production at the Tevatron
Important to have good leading (or leading-log) order QCD Monte-Carlo model predictions of collider observables.
The leading-log QCD Monte-Carlo model estimates are the “base line” from which all other calculations can be compared.
If the leading-log order estimates are within a factor of two of the data, higher order calculations might be expected to improve the agreement.
If a leading-log order estimate is off by more than a factor of two, it usually means that one has overlooked something.
I see no reason why the QCD Monte-Carlo models should not qualitatively describe heavy quark production (in the same way they qualitatively describe light quark and gluon production).
Integrated b-quark Cross Section for PT > PTmin
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
5 10 15 20 25 30 35 40
PTmin (GeV/c)
Cro
ss
Se
cti
on
(b
)
Pythia Creation
Isajet Creation
Herwig Creation
D0 Data
CDF Data
1.8 TeV|y| < 1
CTEQ3L
QCD Monte-Carlo leading order “Flavor Creation” is a factor of four below the data!
“Something is goofy” (Rick Field, CDF B Group Talk, December 3, 1999).
Tevatron Run 1 b-Quark Cross Section
Extrapolation of what is measured (i.e. B-
mesons) to the parton level (i.e. b-quark)!
CDF Run 1 1999
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Rick Field – Florida/CDF/CMS Page 9
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)
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Rick Field – Florida/CDF/CMS Page 10
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!
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Rick Field – Florida/CDF/CMS Page 11
Integrated b-quark Cross Section for PT > PTmin
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E+02
0 5 10 15 20 25 30 35 40
PTmin (GeV/c)
Cro
ss
Se
cti
on
( b
)
PY 6.158 (67=4) Total
Flavor Creation
Flavor Excitation
Shower/Fragmentation
D0 Data
CDF Data
1.8 TeV|y| < 1
PYTHIA 6.158CTEQ3L PARP(67)=4
Inclusive b-quark Cross SectionInclusive b-quark Cross Section
Data on the integrated b-quark total cross section (PT > PTmin, |y| < 1) for proton-antiproton collisions at 1.8 TeV compared with the QCD Monte-Carlo model predictions of PYTHIA 6.158 (CTEQ3L, PARP(67)=4). The four curves correspond to the contribution from “flavor creation”, “flavor excitation”, “gluon splitting”, and the resulting total.
Total
“Flavor Creation”
“Flavor Excitation”
“Gluon Splitting”
Tevatron Run 1 b-Quark Cross Section
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Rick Field – Florida/CDF/CMS Page 12
All three sources are important at the Tevatron!
Conclusions from Run 1Conclusions from Run 1
All three sources are important at the Tevatron and the QCD leading-log Monte-Carlo models do a fairly good job in describing the majority of the b-quark data at the Tevatron.
We should be able experimentally to isolate the individual contributions to b-quark production by studying b-bbar correlations find out in much greater detail how well the QCD Monte-Carlo models actually describe the data.
One has to be very careful when the experimenters extrapolate to the parton level and publish parton level results. The parton level is not an observable! Experiments measure hadrons! To extrapolate to the parton level requires making additional assumptions that may or may not be correct (and often the assumptions are not clearly stated or are very complicated). It is important that the experimenters always publish the corresponding hadron level result along with their parton level extrapolation.
One also has to be very careful when theorists attempt to compare parton level calculations with experimental data. Hadronization and initial/final-state radiation effects are almost always important and theorists should embed their parton level results within a parton-shower/hadronization framework (e.g. HERWIG or PYTHIA).
Proton AntiProton
“Flavor Excitation” b-quark
gluon, quark, or antiquark
Underlying Event Underlying Event
Initial-State Radiation
b-quark
Proton AntiProton
“Flavor Creation” b-quark
b-quark
Underlying Event Underlying Event
Initial-State Radiation
MC@NLO!
“Nothing is goofy” Rick Field, Cambridge Workshop,
July 18, 2002
Proton AntiProton
“Gluon Splitting”
Q-quark
Underlying Event Underlying Event
Initial-State Radiation
Q-quark
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 13
PT AsymmetryPT Asymmetry
Predictions of PYTHIA 6.158 (CTEQ4L, PARP(67)=1) for the asymmetry A = (PT1-PT2)/(PT1+PT2) for events with a b-quark with PT1 > 0 GeV/c and |y1| < 1.0 and a bbar quark with PT2 > 5 GeV/c and |y2| < 1.0 in proton-antiproton collisions at 1.8 TeV. The curves correspond to d/dA (b) for flavor creation, flavor excitation, shower/fragmentation, and the resulting total.
PT1 (b-quark)
“Toward”
“Away”
PT2 (b-quark)
A=(PT1-PT2)/(PT1+PT2) b-quark Correlations: PT Asymmetry
0
1
2
3
4
5
6
7
8
-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0
A=(PT1-PT2)/(PT1+PT2)
d /
dA
( b
)
Pythia Total Flavor Creation Flavor Excitation Shower/Fragmentation
1.8 TeVPT1 > 0 GeV/cPT2 > 5 GeV/c
|y1| < 1 |y2| < 1
Pythia CTEQ4L
PT1 (b-quark)
“Toward”
“Away”
PT2 (b-quark)
A=(PT1-PT2)/(PT1+PT2)
“Flavor Creation”
“Flavor Excitation”
“Gluon Splitting”
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 15
Distance R in Distance R in -- Space Space
Predictions of PYTHIA 6.158 (CTEQ4L, PARP(67)=1) for the distance, R, in - space between the b and bbar-quark with |y1|<1 and |y2|<1 in proton-antiproton collisions at 1.8 TeV. The curves correspond to d/dR (b) for flavor creation, flavor excitation, shower/fragmentation, and the resulting total.
b-quark Correlations: Distance R
0.1
1.0
10.0
0 1 2 3 4 5
Distance R
d /
dR
( b
)
Pythia Total
Flavor Creation
Flavor Excitation
Shower/Fragmentation
1.8 TeVPT1 > 5 GeV/cPT2 > 0 GeV/c|y1| < 1 |y2| < 1
Pythia CTEQ4L
b-quark Correlations: Distance R
0.001
0.010
0.100
1.000
0 1 2 3 4 5
Distance R
d /
dR
( b
)
Pythia Total
Flavor Creation
Flavor Excitation
Shower/Fragmentation
1.8 TeVPT1 > 12 GeV/cPT2 > 6 GeV/c|y1| < 1 |y2| < 1
Pythia CTEQ4L
-1
+1
2 0
R
- Space
b-quark
b-quark
“Gluon Splitting”
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Rick Field – Florida/CDF/CMS Page 17
Azimuthal CorrelationsAzimuthal Correlations
Predictions of PYTHIA 6.206 (CTEQ5L) with PARP(67)=1 (new default) and PARP(67)=4 (old default) for the azimuthal angle, , between a b-quark with PT1 > 15 GeV/c, |y1| < 1 and bbar-quark with PT2 > 10 GeV/c, |y2|<1 in proton-antiproton collisions at 1.8 TeV. The curves correspond to d/d (b/o) for flavor creation, flavor excitation, gluon splitting, and the resulting total.
b-quark Correlations: Azimuthal Distribution
0.00001
0.00010
0.00100
0.01000
0 30 60 90 120 150 180
(degrees)
d /
d
(b
/deg
)
PY62 (67=1) Total Flavor Creation Flavor Excitation Shower/Fragmentation
1.8 TeVPT1 > 15 GeV/cPT2 > 10 GeV/c|y1| < 1 |y2| < 1
PYTHIA 6.206 CTEQ5L PARP(67)=1
"Away""Toward"
b-quark direction
“Toward”
“Away”
bbar-quark
b-quark Correlations: Azimuthal Distribution
0.00001
0.00010
0.00100
0.01000
0 30 60 90 120 150 180
(degrees)
d /
d
(b
/de
g)
PY62 (67=4) Total Flavor Creation Flavor Excitation Shower/Fragmentation
1.8 TeVPT1 > 15 GeV/cPT2 > 10 GeV/c|y1| < 1 |y2| < 1
PYTHIA 6.206 CTEQ5L PARP(67)=4
"Away""Toward"
New PYTHIA default(less initial-state radiation)
Old PYTHIA default(more initial-state radiation)
“Flavor Creation”
“Flavor Excitation”
“Gluon Splitting”
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 18
Azimuthal CorrelationsAzimuthal Correlations
Predictions of HERWIG 6.4 (CTEQ5L) for the azimuthal angle, , between a b-quark with PT1 > 15 GeV/c, |y1| < 1 and bbar-quark with PT2 > 10 GeV/c, |y2|<1 in proton-antiproton collisions at 1.8 TeV. The curves correspond to d/d (b/o) for flavor creation, flavor excitation, shower/fragmentation, and the resulting total.
b-quark Correlations: Azimuthal Distribution
0.00001
0.00010
0.00100
0.01000
0 30 60 90 120 150 180
(degrees)
d /
d
(b
/de
g)
HW64 Total Flavor Creation Flavor Excitation Shower/Fragmentation
1.8 TeVPT1 > 15 GeV/cPT2 > 10 GeV/c|y1| < 1 |y2| < 1
HERWIG 6.4 CTEQ5L
"Away""Toward"
b-quark direction
“Toward”
“Away”
bbar-quark
b-quark Correlations: Azimuthal Distribution
0.000001
0.000010
0.000100
0.001000
0.010000
0 30 60 90 120 150 180
(degrees)
d /
d
(b
/deg
)
1.8 TeVPT1 > 15 GeV/cPT2 > 10 GeV/c|y1| < 1 |y2| < 1
"Flavor Creation" CTEQ5L
"Away""Toward"
HERWIG 6.4
PYTHIA 6.206PARP(67)=1
PYTHIA 6.206PARP(67)=4
“Flavor Creation”
New PYTHIA default(less initial-state radiation)
Old PYTHIA default(more initial-state radiation)
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 19
CDF Run I AnalysisCDF Run I AnalysisAzimuthal CorrelationsAzimuthal Correlations
Run I CDF data for the azimuthal angle, , between a b-quark |y1| < 1 and bbar-quark |y2|<1 in proton-antiproton collisions at 1.8 TeV favored PYTHIA Tune A (PARP(67) = 4).
b-quark Correlations: Azimuthal Distribution
0.00001
0.00010
0.00100
0.01000
0 30 60 90 120 150 180
(degrees)
d /
d
(b
/de
g)
PY62 (67=4) Total Flavor Creation Flavor Excitation Shower/Fragmentation
1.8 TeVPT1 > 15 GeV/cPT2 > 10 GeV/c|y1| < 1 |y2| < 1
PYTHIA 6.206 CTEQ5L PARP(67)=4
"Away""Toward"
b-quark direction
“Toward”
“Away”
bbar-quark
b-quark Correlations: Azimuthal Distribution
0.0001
0.0010
0.0100
0.1000
0 30 60 90 120 150 180
(degrees)
1/
d /
d
(b
/de
g)
CDF Preliminary Data 1.8 TeV
"Away""Toward"
Kevin Lannon DPF2002Now published!
b-quark Correlations: Azimuthal Distribution
0.00001
0.00010
0.00100
0.01000
0 30 60 90 120 150 180
(degrees)
d /
d
(b
/de
g)
PY62 (67=4) Total Flavor Creation Flavor Excitation Shower/Fragmentation
1.8 TeVPT1 > 15 GeV/cPT2 > 10 GeV/c|y1| < 1 |y2| < 1
PYTHIA 6.206 CTEQ5L PARP(67)=4
"Away""Toward"
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 20
The Run 2 J/The Run 2 J/ Cross Section Cross Section
The J/ inclusive cross-section includes contribution from the direct production of J/ and from decays from excited charmonium, (2S), and from the decays of b-hadrons, B→ J/ + X.
CDF (b)
(J/|Y(J/)| < 0.6)
4.080.02(stat)+0.36(sys)-0.48(sys)
Down to PT = 0!
J/
KB
J/ coming from b-hadrons
will be displaced from primary vertex!
39.7 pb-1
Primary vertex(i.e. interaction point)
4.8 pb-1
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 21
CDF Run 2 B-hadron Cross Section CDF Run 2 B-hadron Cross Section
Run 2 B-hadron PT distribution compared with FONLL (CTEQ6M).
B-hadron pT
CDF (b) FONLL (b)
(B-hadron) 29.40.6(stat)6.2(sys) 27.5+11-8.2
|Y| < 1.0
Good agreement between theory and experiment!
39.7 pb-1
Cacciari, Frixone, Mangano, Nason, Ridolfi
PRD 71, 032001 (2005)
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Rick Field – Florida/CDF/CMS Page 22
CDF Run 2 b-Jet Cross SectionCDF Run 2 b-Jet Cross Section
b-quark tag based on displaced vertices. Secondary vertex mass discriminates flavor.
Require one secondary vertex tagged b-jet within 0.1 < |y|< 0.7 and plot the inclusive jet PT distribution (MidPoint, R = 0.7).
Collision point
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 23
CDF Run 2 b-Jet Cross SectionCDF Run 2 b-Jet Cross Section
Shows the CDF inclusive b-jet cross section (MidPoint, R = 0.7, fmerge = 0.75) at 1.96 TeV with L = 300 pb-1.
Shows data/theory for NLO (with large scale uncertainties).
Shows data/theory for PYTHIA Tune A.
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Rick Field – Florida/CDF/CMS Page 24
The b-bbar DiJet Cross-SectionThe b-bbar DiJet Cross-Section
ET(b-jet#1) > 30 GeV, ET(b-jet#2) > 20 GeV, |(b-jets)| < 1.2.
Differential Cross Section as a function of the b-bbar DiJet invariant mass!
Preliminary CDF Results:
bb = 34.5 1.8 10.5 nbQCD Monte-Carlo Predictions:
PYTHIA Tune A CTEQ5L
38.71 ± 0.62 nb
HERWIG CTEQ5L 21.53 ± 0.66 nb
MC@NLO 28.49 ± 0.58 nb
Proton AntiProton
“Flavor Creation” b-quark
b-quark
Underlying Event Underlying Event
Initial-State Radiation
Predominately Flavor creation!
SystematicUncertainty
Large Systematic Uncertainty: Jet Energy Scale (~20%). b-tagging Efficiency (~8%)
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Rick Field – Florida/CDF/CMS Page 25
The b-bbar DiJet Cross-SectionThe b-bbar DiJet Cross-Section
ET(b-jet#1) > 30 GeV, ET(b-jet#2) > 20 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 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 26
b-bbar DiJet Correlationsb-bbar DiJet Correlations
The two b-jets are predominately “back-to-back” (i.e. “flavor creation”)!
Pythia Tune A agrees fairly well with the correlation!
Differential Cross Section as a function of of the two b-jets!
Proton AntiProton
“Flavor Creation” b-quark
b-quark
Underlying Event Underlying Event
Initial-State Radiation
Tune A!
b-jet direction
“Toward”
“Away”
bbar-jet
Not an accident!
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 27
Top Production at the TevatronTop Production at the Tevatron
Top quark discovered in 1995 by CDF and DØ.
Not a surprise: SM quark sector now complete.
Now study the detailed properties of the top:
• Charge.• Lifetime.• Branching ratios.• W-boson helicity.
Make precision measurements:
• Cross-sections now 12%!• Mass now 2%!
Measure single top production!
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 28
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
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 29
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 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 30
Lepton+Jets Channel (CDF)Lepton+Jets Channel (CDF)KinematicsKinematics
Selection:• 1 lepton with pT > 20 GeV/c.• >= 3 jets with pT > 15GeV/c.• Missing ET > 20 GeV.
Backgrounds:
• W+jets
• QCD
spherical
central
binned likelihood fit
Use 7 kinematic variables in neural net to discriminate signal from background!
One of the 7 variables!
(tt) = 6.0 ± 0.6 (stat) ± 0.9 (syst) pb
Neural net output!
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 31
Lepton+Jets Channel (CDF)Lepton+Jets Channel (CDF)
HT>200GeV
2 b tags
(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%
1 b tag
~150 events
Small background!
(tt) = 8.2 ± 0.6 (stat) ± 1.1 (syst) pb
~45 events
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Rick Field – Florida/CDF/CMS Page 32
All Hadronic Channel (DAll Hadronic Channel (DØ)Ø)Selection:
• >=6 jets with pT > 15 GeV/c.• >=1 b tagged.• NN discriminant > 0.9.
Huge QCD background!
Geometric mean of 5th and 6th leading jet ET
Use 6 kinematic variables in neural net to discriminate signal from background!
One of the 6 variables!
(tt ) 5.2 2.52.6 (stat) 1.0
1.5 (syst) 0.3(lumi)pb
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Rick Field – Florida/CDF/CMS Page 33
Tevatron Top-Pair Cross SectionTevatron Top-Pair Cross Section
(tt ) 6.7 0.90.7 pb
Bonciani et al., Nucl. Phys. B529, 424 (1998)Kidonakis and Vogt, Phys. Rev. D68, 114014 (2003)
Theory
CDF Run 2 Preliminary
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New CDF MNew CDF Mtoptop Results Results
CDF Lepton+jets: Mtop (template) = 173.4 ± 2.5 (stat. + jet E) ± 1.3 (syst.) GeVMtop (matrix element) = 174.1 ± 2.5 (stat. + jet E) ± 1.4 (syst.) GeV
Mtop (Lxy) = 183.9 +15.7-13.9 (stat.) ± 5.6 (syst.) GeV
CDF Dilepton: Mtop (matrix element) = 164.5 ± 4.5 (stat.) ± 3.1 (jet E. + syst.) GeV
Transverse decay length!
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 35
Top Quark MassTop Quark MassSummer 2005
Dilepton: CDF-II Mtop
ME = 164.5 ± 5.5 GeV
Lepton+Jets: CDF-II Mtop
Temp = 174.1 ± 2.8 GeV CDF-II Mtop
ME = 173.4 ± 2.9 GeV
CDF Combined: Mtop
CDF = 172.0 ± 1.6 ± 2.2 GeV = 172.0 ± 2.7 GeV
New since Summer 2005
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 36
Top Cross-Section vs MassTop Cross-Section vs Mass
Tevatron Summer 2005 CDF Winter 2006
Updated CDF+DØ combined result is coming soon!
CDF combined
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 37
Is Anything “Goofy”?Is Anything “Goofy”? Possible discrepancy between
l + jets and the dilepton channel measurements of the top mass??
Is it statistical?
• ME(dilepton) vs Templ(l+jets):2 = 2.9/1, Prob = 0.09 (accounts for correlated systematics).
Is there a missing systematic? This is probably nothing, but
we should keep an eye on it!
IMFP2006 - Day 2 April 4, 2006
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Future Top Mass MeasurementsFuture Top Mass Measurements
Expect significant reduction in jet energy scale uncertainty with more data. Today we have CDF-II Mtop(Temp) = 174.1 ± 2.8 GeV (~0.7 fb-1).
CDF should be able to achieve 1.5 GeV uncertainty on top mass!
Systematic Source
Uncertainty
(GeV/c2)
ISR/FSR 0.7
Model 0.7
b-jet 0.6
Method 0.6
PDF 0.3
Total 1.3
Jet Energy 2.5
CDF
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 39
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
This spring?
Summer 05
114 GeV Higgs very interesting for the Tevatron!
IMFP2006 - Day 2 April 4, 2006
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Top: Charge, Branching, Lifetime, W HelicityTop: Charge, Branching, Lifetime, W Helicity
DØ Prelim.365 pb-1
Top Charge
top< 1.75x10-13sctop< 52.5m
at 95%CL
Exclude |Q| = 4/3 at 94% CL
Reconstructed Top Charge (e)
SM
bgrnd
signal
f+ (DØ combined) = 0.04 ± 0.11(stat) ± 0.06(syst)
f+ (SM pred.) = 0
signal+bgrnd
370 pb-1
hep-ex/0603002
CDF Prelim.318 pb-1
Top Lifetime
Impact Parameter (m)
Everything consistent with the Standard Model!
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 43
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%
IMFP2006 - Day 2 April 4, 2006
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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
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 45
New Single Top Results from CDFNew Single Top Results from CDF To the network 2D output, CDF applies a
maximum likelihood fit and the best fits for t and s-channels are:
(syst)pb(stat)0.6σ 0.10.1
1.90.6cht
t-channel:
< 3.1 pb @ 95% C.L.
s-channel:
< 3.2 pb @ 95% C.L.
pb (syst)(stat)0.3σ 0.50.3-
2.20.3chs
The new CDF limits!
IMFP2006 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 46
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 !!!!
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 - Day 2 April 4, 2006
Rick Field – Florida/CDF/CMS Page 47
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!