The Tevatron Connection
Rick Field
University of Florida
(for the CDF Collaboration)
“Flavor Creation”
Multiple Parton Interactions
b-quark
Outgoing Parton
PT(hard)
Proton
Proton
AntiProton
Underlying Event
AntiProton
Underlying Event
Underlying Event
Underlying Event
Initial-State
Radiation
b-quark
The Tevatron Connection
June 24, 2005
CDF Run 2
Rick Field - Florida/CDF
Outgoing Parton
Page 1
Jet Physics
in Run 2 at CDF
“Hard” Scattering
Outline of Talk
Outgoing Parton
PT(hard)
Proton
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
Final-State
Radiation
Calorimeter Jet
¨ Constructing Jets in Run 2 at CDF
(MidPoint and KT Algorithms).
¨ New from CDF: The KT-Jet
Outgoing Parton
High PT “jets”
probe short
distances!
Inclusive Cross Section.
¨ New from CDF: The b-Jet Inclusive
KT Algorithm
Cross Section.
¨ New from CDF: The b-bbar Jet Cross
Section and Correlations.
¨ Understanding and Modeling the
“Underlying Event” in Run 2 at CDF.
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 2
CDF-QCD Group
CDF-QCD Group
Learn more about how nature works. Compare
with theory and work to provide information that
will lead to improved Monte-Carlo models and
structure functions. Our contributions will
benefit to the colliders of the future!
Some CDF-QCD Group Analyses!
¨
¨
¨
¨
¨
¨
¨
Jet Cross Sections and Correlations: JetClu, MidPoint, KT algorithms.
DiJet Mass Distributions: ∆φ distribution, compositness.
Heavy Flavor Jets: b-jet and b-bbar jet cross sections and correlations.
Z and W Bosons plus Jets: including b-jets.
Jets Fragmentation: jet shapes, momentum distributions, two-particle correlations.
Underlying Event Studies: charged particles and energy for jet, jet+jet, γ+jet, Z+jet.
Pile-Up Studies: modeling of pile-up.
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Important for the LHC!
Page 3
Jets at 1.96 TeV
“Real Jets”
“Theory Jets”
Next-to-leading order
parton level calculation
0, 1, 2, or 3 partons!
¨ Experimental Jets: The study of “real” jets requires a “jet algorithm” and the different
algorithms correspond to different observables and give different results!
¨ 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”!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 4
KT Algorithm
¨
Begin
kT Algorithm:
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
For each precluster, calculate
di = pT2 ,i
For each pair of preculsters, calculate
( y − y j ) 2 + (φi − φ j ) 2
d ij = min( pT2 ,i , pT2 , j ) i
D2
Find the minimum of all di and dij.
Merge
i and j
yes
Minumum
is dij?
no
Move i to list of jets
yes
Any
Preclusters
left?
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!
Will the KT algorithm be
effective in the collider
environment where there is
an “underlying event”?
Raw Jet ET = 533 GeV
KT Algorithm
Raw Jet ET = 618 GeV
no
End
Outgoing Parton
PT(hard)
Initial-State Radiation
Proton
AntiProton
Underlying Event
Underlying Event
CDF Run 2
Outgoing Parton
Final-State
Radiation
The Tevatron Connection
June 24, 2005
Only towers with ET > 0.5 GeV are shown
Rick Field - Florida/CDF
Page 5
Jet Corrections
¨
Calorimeter Jets:
ƒ
ƒ
ƒ
ƒ
¨
Particle Level Jets:
ƒ
ƒ
ƒ
¨
Outgoing Parton
PT(hard)
Initial-State Radiation
Proton
AntiProton
Underlying Event
Outgoing Parton
Underlying Event
Final-State
Radiation
The Tevatron Connection
June 24, 2005
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!
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.
Parton Level Jets:
ƒ
ƒ
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 MonteCarlo 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.
Rick Field - Florida/CDF
Page 6
Jet Corrections
Theory
Experiment
I believe we should correct the
data back to what we measure
(i.e. the particle level with an
“underlying
event”)!
¨ Calorimeter
Jets:
ƒ We measure “jets” at the “hadron level” in the calorimeter.
ƒ We certainly want to correct the “jets” for the detector resolution and
effieciency.
ƒ should
Also, we
must(or
correct the “jets” for “pile-up”.
I believe we
correct
ƒ theory
Must correct
calculate) the
for whatwhat
we we measure back to the true “particle level” jets!
measure (i.e. the particle level
¨ an Particle
Level
Jets:
with
“underlying
event”)!
ƒ MC@NLO!
Do we want to make further model dependent corrections?
We need
ƒ Do we want to try and subtract the “underlying event” from the
“particle level” jets.
ƒ 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.
¨
Parton Level Jets:
ƒ
Outgoing Parton
ƒ
PT(hard)
Initial-State Radiation
Proton
AntiProton
Underlying Event
Outgoing Parton
Underlying Event
Final-State
Radiation
The Tevatron Connection
June 24, 2005
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 MonteCarlo 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.
Rick Field - Florida/CDF
Page 7
KT Jet Cross-Section
NLO parton level theory
corrected to the “particle level”!
Data at the “particle level”!
Correction factors
applied to NLO theory!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 8
KT Jet Cross-Section
NLO parton level theory
corrected to the “particle level”!
Data at the “particle level”!
7
7
8
Correction factors
applied to NLO theory!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 9
Data at the “hadron level”!
KT Jet Cross-Section
NLO parton level theory
corrected to the “hadron level”!
Theory and experiment agree
very well! The KT algorithm
works fine at the collider!
Correction factors
applied to NLO theory!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 10
Construct the invariant mass
of particles pointing back to
the secondary vertex!
The b-Jet Inclusive
Cross-Section
98 < pT(jet) < 106 GeV/c
Monte-Carlo Templates
¨ Extract fraction of b-tagged jets from data using the shape of
the mass of the secondary vertex as discriminating quantity
(bin-by-bin as a function of jet pT).
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 11
“Flavor Creation”
The b-Jet Inclusive
Cross-Section
b-quark
Proton
Inclusive b-Jet Cross Section
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
b-quark
“Flavor Excitation”
b-quark
Proton
AntiProton
Underlying Event
Underlying Event
b-quark
Initial-State
Radiation
gluon, quark,
or antiquark
“Parton Shower/Fragmentation”
Proton
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
b-quark
b-quark
¨ The data are compared with
PYTHIA (tune A)! Data/PYA ~ 1.4
¨ Comparison with MC@NLO
coming soon!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 12
The b-bbar DiJet
Cross-Section
¨ ET(b-jet#1) > 30 GeV, ET(b-jet#2) > 20
GeV, |η(b-jets)| < 1.2.
Systematic
Preliminary CDF Results:
Uncertainty
σbb = 34.5 ± 1.8 ± 10.5 nb
QCD Monte-Carlo Predictions:
PYTHIA Tune A
CTEQ5L
38.71 ± 0.62nb
HERWIG CTEQ5L
21.53 ± 0.66nb
MC@NLO
28.49 ± 0.58nb
“Flavor Creation”
Proton
Differential Cross Section as a function of
the b-bbar DiJet invariant mass!
b-quark
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
Predominately
Flavor creation!
b-quark
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
¨ Large Systematic Uncertainty:
ƒ Jet Energy Scale (~20%).
ƒ b-tagging Efficiency (~8%)
Page 13
The b-bbar DiJet
Cross-Section
¨ ET(b-jet#1) > 30 GeV, ET(b-jet#2) > 20
GeV, |η(b-jets)| < 1.2.
Preliminary CDF Results:
σbb = 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!
JIMMY
Runs with HERWIG and adds
multiple parton interactions!
“Flavor Creation”
b-quark
Initial-State Radiation
JIMMY: MPI
J. M. Butterworth
J. R. Forshaw
M. H. Seymour
Adding multiple parton interactions
(i.e. Jimmy) to enhance the “underlying
event” increases the b-bbar jet cross
section!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Proton
AntiProton
Underlying Event
Underlying Event
b-quark
Final-State
Radiation
Page 14
b-bbar DiJet
Correlations
Tune A!
b-jet direction
∆φ
“Toward”
“Away”
bbar-jet
Differential Cross Section as a
function of ∆φ of the two b-jets!
¨ The two b-jets are predominately “back-toback” (i.e. “flavor creation”)!
“Flavor Creation”
¨ Pythia Tune A agrees fairly well with the ∆φ
correlation!
Proton
b-quark
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
Not an
accident!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
b-quark
Page 15
b-bbar DiJet
Correlations
Tune A!
¨ The two b-jets are predominately “backto-back” (i.e. “flavor creation”)!
“Flavor Creation”
b-quark
Proton
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
Differential Cross Section as a
function of ∆φ of the two b-jets!
b-quark
¨ Pythia Tune A agrees fairly well with the ∆φ
correlation!
“Flavor Creation”
b-quark
Initial-State Radiation
Proton
AntiProton
Underlying Event
Underlying Event
b-quark
Final-State
Radiation
¨ Agrees very well with MC@NLO + HERWIG + JIMMY!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 16
b-Jet bbar-Jet
Correlations
Tune A!
¨ The two b-jets are predominately “backto-back” (i.e. “flavor creation”)!
“Flavor Creation”
b-quark
Proton
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
The “underlying event” is
important in jet (and b-jet)
¨ Pythia Tune A agrees fairly
well with theat
∆φthe Tevatron!
production
b-quark
correlation!
“Flavor Creation”
Differential Cross Section as a
function of ∆φ of the two b-jets!
b-quark
Initial-State Radiation
Proton
AntiProton
Underlying Event
Underlying Event
b-quark
Final-State
Radiation
¨ Agrees very well with MC@NLO + HERWIG + JIMMY!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 17
The “Underlying Event”
in Run 2 at CDF
Jet #1 Direction
∆φ
The “underlying event” consists of
hard initial & final-state radiation
plus the “beam-beam remnants” and
possible multiple parton interactions.
Outgoing Parton
PT(hard)
“Toward”
Initial-State Radiation
“Trans 1”
“Trans 2”
Proton
AntiProton
Underlying Event
Underlying Event
“Away”
“Transverse” region is
very sensitive to the
“underlying event”!
Outgoing Parton
Final-State
Radiation
CDF Run 2 results:
¨
¨
¨
¨
¨
¨
Two Classes of Events: “Leading Jet” and “Back-to-Back”.
Two “Transverse” regions: “transMAX”, “transMIN”, “transDIF”.
PTmax and PTmaxT distributions and averages.
∆φ Distributions: “Density” and “Associated Density”.
<pT> versus charged multiplicity: “min-bias” and the “transverse” region.
Correlations between the two “transverse” regions: “trans1” vs “trans2”.
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 18
The “Transverse” Regions
as defined by the Leading Jet
Jet #1 Direction
“Transverse” region is
very sensitive to the
“underlying event”!
Charged Particle ∆φ Correlations
2π
pT > 0.5 GeV/c |η| < 1
“Toward-Side” Jet
∆φ
Look at the charged
particle density in the
“transverse” region!
Away Region
Jet #1 Direction
Transverse
Region 1
∆φ
“Toward”
“Toward”
“Transverse”
“Transverse”
“Trans 1”
φ
Leading
Jet
“Trans 2”
Toward Region
Transverse
Region 2
“Away”
“Away”
Away Region
“Away-Side” Jet
0
-1
η
+1
¨ Look at charged particle correlations in the azimuthal angle ∆φ relative to the leading
calorimeter jet (JetClu R = 0.7, |η| < 2).
¨ Define |∆φ| < 60o as “Toward”, 60o < -∆φ < 120o and 60o < ∆φ < 120o as “Transverse 1” and
“Transverse 2”, and |∆φ| > 120o as “Away”. Each of the two “transverse” regions have
area ∆η∆φ = 2x60o = 4π/6. The overall “transverse” region is the sum of the two
transverse regions (∆η∆φ = 2x120o = 4π/3).
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 19
Tuned PYTHIA 6.206
CDF Default!
PYTHIA 6.206 CTEQ5L
Tune B
Tune A
MSTP(81)
1
1
MSTP(82)
4
4
PARP(82)
1.9 GeV
2.0 GeV
PARP(83)
0.5
0.5
PARP(84)
0.4
0.4
PARP(85)
1.0
0.9
PARP(86)
1.0
0.95
PARP(89)
1.8 TeV
1.8 TeV
PARP(90)
0.25
0.25
PARP(67)
1.0
4.0
New PYTHIA default
(less initial-state radiation)
The Tevatron Connection
June 24, 2005
1.00
"Transverse" Charged Density
Parameter
"Transverse" Charged Particle Density: dN/dηdφ
CDF Preliminary
PYTHIA 6.206 (Set A)
PARP(67)=4
data uncorrected
theory corrected
0.75
Run 1 Analysis
0.50
0.25
CTEQ5L
PYTHIA 6.206 (Set B)
PARP(67)=1
1.8 TeV |η|<1.0 PT>0.5 GeV
0.00
0
5
10
15
20
25
30
35
40
45
50
PT(charged jet#1) (GeV/c)
¨ Plot shows the “Transverse” charged particle density
versus PT(chgjet#1) compared to the QCD hard
scattering predictions of two tuned versions of
PYTHIA 6.206 (CTEQ5L, Set B (PARP(67)=1) and
Set A (PARP(67)=4)).
Old PYTHIA default
(more initial-state radiation)
Rick Field - Florida/CDF
Page 20
Run 1 b-quark
Azimuthal Correlations
PYTHIA Tune A
(more initial-state radiation)
PYTHIA Tune B
(less initial-state radiation)
b-quark Correlations: Azimuthal ∆φ Distribution
b-quark Correlations: Azimuthal ∆φ Distribution
0.01000
0.01000
1.8 TeV
PT1 > 15 GeV/c
PT2 > 10 GeV/c
|y1| < 1 |y2| < 1
PYTHIA 6.206
CTEQ5L PARP(67)=1
dσ/dφ (µb/deg)
dσ/dφ (µb/deg)
1.8 TeV
PT1 > 15 GeV/c
PT2 > 10 GeV/c
|y1| < 1 |y2| < 1
0.00100
0.00010
0.00100
0.00010
"Away"
"Toward"
"Away"
"Toward"
PYTHIA 6.206
CTEQ5L PARP(67)=4
0.00001
0.00001
0
30
60
90
120
150
180
0
30
60
|∆φ| (degrees)
PY62 (67=1) Total
Flavor Creation
Flavor Excitation
90
120
150
180
|∆φ| (degrees)
Shower/Fragmentation
PY62 (67=4) Total
Flavor Creation
Flavor Excitation
Shower/Fragmentation
b-quark
direction
¨
Predictions of PYTHIA 6.206 (CTEQ5L) with PARP(67)=1
(new default, Tune B) and PARP(67)=4 (old default, Tune A)
for the azimuthal angle, ∆φ, 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 dσ/d∆φ (µb/o) for flavor creation, flavor excitation,
shower/fragmentation, and the resulting total.
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
∆φ
“Toward”
“Away”
bbar-quark
Page 21
Run 1 b-quark
Azimuthal Correlations
PYTHIA Tune A
(more initial-state radiation)
b-quark Correlations: Azimuthal ∆φ Distribution
b-quark Correlations: Azimuthal ∆φ Distribution
0.01000
0.010000
1.8 TeV
PT1 > 15 GeV/c
PT2 > 10 GeV/c
|y1| < 1 |y2| < 1
HERWIG 6.4
CTEQ5L
0.001000
0.00100
dσ/dφ (µb/deg)
dσ/dφ (µb/deg)
1.8 TeV
PT1 > 15 GeV/c
PT2 > 10 GeV/c
|y1| < 1 |y2| < 1
0.00010
"Flavor Creation"
CTEQ5L
HERWIG 6.4
0.000100
PYTHIA 6.206
PARP(67)=4
PYTHIA 6.206
PARP(67)=1
0.000010
"Away"
"Toward"
0.00001
30
60
90
120
150
180
|∆φ| (degrees)
HW64 Total
¨
"Away"
"Toward"
0
Flavor Creation
Flavor Excitation
0.000001
0
30
60
Predictions of HERWIG 6.4 (CTEQ5L) for the
azimuthal angle, ∆φ, 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
dσ/d∆φ (µb/o) for flavor creation, flavor
excitation, shower/fragmentation, and the
resulting total.
90
120
150
180
|∆φ| (degrees)
Shower/Fragmentation
b-quark
direction
PYTHIA Tune B
(less initial-state radiation)
∆φ
“Toward”
“Away”
“Flavor Creation”
bbar-quark
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 22
CDF Run I Analysis
Azimuthal Correlations
b-quark Correlations: Azimuthal ∆φ Distribution
b-quark Correlations: Azimuthal ∆φ Distribution
0.1000
0.01000
1.8 TeV
PT1 > 15 GeV/c
PT2 > 10 GeV/c
|y1| < 1 |y2| < 1
1.8 TeV
dσ/dφ (µb/deg)
1/σ dσ/dφ (µb/deg)
CDF Preliminary Data
0.0100
0.0010
PYTHIA 6.206
CTEQ5L PARP(67)=4
0.00100
0.00010
"Away"
"Toward"
"Away"
"Toward"
0.00001
0
0.0001
0
30
60
90
|∆φ| (degrees)
120
150
30
60
90
120
150
180
|∆φ| (degrees)
180
PY62 (67=4) Total
Flavor Creation
Flavor Excitation
¨ Run I preliminary uncorrected CDF data for the
Preliminary CDF Run 1
azimuthal angle, ∆φ, between a b-quark |y1| < 1 and bbarb-bbar quark ∆φ!
quark |y2|<1 in proton-antiproton collisions at 1.8 TeV.
Shower/Fragmentation
b-quark
direction
∆φ
“Toward”
¨ PYTHIA Tune A (with more initial state radiation)
agreed better with the CDF Run 1 data!
¨ Thus we choose Tune A over Tune B as the CDF default!
“Away”
bbar-quark
Now Published!
Phys. Rev. D71, 092001 (2005)
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 23
Refer to this as a
“Leading Jet” event
Charged Particle Density
∆φ Dependence Run 2
Jet #1 Direction
∆φ
Charged Particle Density: dN/dηdφ
“Toward”
“Transverse”
“Transverse”
“Away”
Refer to this as a
“Back-to-Back” event
Jet #1 Direction
∆φ
“Toward”
“Transverse”
Charged Particle Density
Subset
10.0
CDF Preliminary
30 < ET(jet#1) < 70 GeV
Back-to-Back
Leading Jet
data uncorrected
Min-Bias
"Transverse"
Region
1.0
Jet#1
Charged Particles
(|η|<1.0, PT>0.5 GeV/c)
“Transverse”
0.1
“Away”
0
30
60
90
120
150
180
210
240
270
300
330
360
∆φ (degrees)
Jet #2 Direction
¨ Look at the “transverse” region as defined by the leading jet (JetClu R = 0.7, |η| < 2) or
by the leading two jets (JetClu R = 0.7, |η| < 2). “Back-to-Back” events are selected to
have at least two jets with Jet#1 and Jet#2 nearly “back-to-back” (∆φ12 > 150o) with
almost equal transverse energies (ET(jet#2)/ET(jet#1) > 0.8) and ET(jet#3) < 15 GeV.
¨ Shows the ∆φ dependence of the charged particle density, dNchg/dηdφ, for charged
particles in the range pT > 0.5 GeV/c and |η| < 1 relative to jet#1 (rotated to 270o) for 30
< ET(jet#1) < 70 GeV for “Leading Jet” and “Back-to-Back” events.
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 24
“Transverse” PTsum Density
PYTHIA Tune A vs HERWIG
“Leading Jet”
Jet #1 Direction
∆φ
"AVE Transverse" PTsum Density: dPT/dηdφ
“Toward”
“Transverse”
“Transverse”
“Away”
“Back-to-Back”
Jet #1 Direction
∆φ
“Toward”
“Transverse”
“Transverse”
"Transverse" PTsum Density (GeV/c)
1.4
Leading Jet
CDF Preliminary
1.2
data uncorrected
theory + CDFSIM
1.0
PY Tune A
0.8
0.6
0.4
Back-to-Back
HW
0.2
1.96 TeV
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
0
50
100
150
200
250
ET(jet#1) (GeV)
“Away”
Jet #2 Direction
Now look in detail at “back-to-back” events in
the region 30 < ET(jet#1) < 70 GeV!
¨ Shows the average charged PTsum density, dPTsum/dηdφ, in the “transverse” region (pT
> 0.5 GeV/c, |η| < 1) versus ET(jet#1) for “Leading Jet” and “Back-to-Back” events.
¨ Compares the (uncorrected) data with PYTHIA Tune A and HERWIG after CDFSIM.
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 25
Charged PTsum Density
PYTHIA Tune A vs HERWIG
HERWIG (without multiple parton
interactions) does not produces
enough PTsum in the “transverse”
region for 30 < ET(jet#1) < 70 GeV!
Charged PTsum Density: dPT/dηdφ
Charged PTsum Density: dPT/dηdφ
100.0
Charged Particles
30 < ET(jet#1) < 70 GeV
(|η|<1.0, PT>0.5 GeV/c)
Back-to-Back
PY Tune A
Charged PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
100.0
10.0
1.0
CDF Preliminary
Jet#1
"Transverse"
Region
data uncorrected
theory + CDFSIM
Charged Particles
30 < ET(jet#1) < 70 GeV
(|η|<1.0, PT>0.5 GeV/c)
Back-to-Back
HERWIG
10.0
"Transverse"
Region
1.0
CDF Preliminary
0.1
0.1
0
30
60
90
120
150
180
210
240
270
300
330
360
0
30
60
90
120
∆φ (degrees)
data uncorrected
theory + CDFSIM
Back-to-Back
30 < ET(jet#1) < 70 GeV
PYTHIA Tune A
CDF Preliminary
0
-1
"Transverse"
Region
Charged Particles
(|η|<1.0, PT>0.5 GeV/c)
180
210
240
270
300
330
360
330
360
Data - Theory: Charged PTsum Density dPT/dηdφ
2
Data - Theory (GeV/c)
Data - Theory (GeV/c)
CDF Preliminary
150
∆φ (degrees)
Data - Theory: Charged PTsum Density dPT/dηdφ
2
1
Jet#1
data uncorrected
theory + CDFSIM
data uncorrected
theory + CDFSIM
1
30 < ET(jet#1) < 70 GeV
Back-to-Back
HERWIG
0
-1
"Transverse"
Region
Charged Particles
(|η|<1.0, PT>0.5 GeV/c)
Jet#1
Jet#1
-2
-2
0
30
60
90
120
150
180
210
240
270
300
330
360
0
30
90
120
150
180
210
240
270
300
∆φ (degrees)
∆φ (degrees)
The Tevatron Connection
June 24, 2005
60
Rick Field - Florida/CDF
Page 26
Tuned JIMMY versus
PYTHIA Tune A
JIMMY: MPI
J. M. Butterworth
J. R. Forshaw
M. H. Seymour
JIMMY
Runs with HERWIG and adds
multiple parton interactions!
Charged PTsum Density: dPT/dηdφ
Charged PTsum Density: dPT/dηdφ
100.0
Charged Particles
30 < ET(jet#1) < 70 GeV
(|η|<1.0, PT>0.5 GeV/c)
Leading Jet
PY Tune A
Charged PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
100.0
10.0
1.0
CDF Preliminary
0.1
0
30
60
90
Jet#1
"Transverse"
Region
data uncorrected
theory + CDFSIM
RDF Preliminary
generator level
PYA TOT
JM TOT
10.0
Charged Particles
(|η|<1.0, PT>0.5 GeV/c)
JIMMY tuned to agree
with PYTHIA Tune A!
PT(jet#1) > 30 GeV/c
JM 2-to-2
"Transverse"
Region
JM ISR
JM MPI
1.0
Jet#1
0.1
120
150
180
210
240
270
300
330
360
0
30
∆φ (degrees)
60
90
120
150
180
210
240
270
300
330
360
∆φ (degrees)
¨ (left) Shows the Run 2 data on the ∆φ dependence of the charged scalar PTsum density (|η|<1, pT>0.5
GeV/c) relative to the leading jet for 30 < ET(jet#1) < 70 GeV/c compared with PYTHIA Tune A
(after CDFSIM).
¨ (right) Shows the generator level predictions of PYTHIA Tune A and a tuned version of JIMMY
(PTmin=1.8 GeV/c) for the ∆φ dependence of the charged scalar PTsum density (|η|<1, pT>0.5 GeV/c)
relative to the leading jet for PT(jet#1) > 30 GeV/c. The tuned JIMMY and PYTHIA Tune A agree
in the “transverse” region.
¨ (right) For JIMMY the contributions from the multiple parton interactions (MPI), initial-state
radiation (ISR), and the 2-to-2 hard scattering plus finial-state radiation (2-to-2+FSR) are shown.
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 27
JIMMY (MPI) versus
HERWIG (BBR)
Charged PTsum Density: dPT/dηdφ
ETsum Density: dET/dηdφ
2.5
generator level
0.8
JM MPI
0.6
HW BBR
"Transverse"
Region
0.4
0.2
0
30
60
90
generator level
2.0
150
180
210
240
270
300
330
360
PT(jet#1) > 30 GeV
1.0
0.5
0
30
∆φ (degrees)
60
90
Jet#1
"Transverse"
Region
All Particles
(|η|<1.0, PT>0 GeV/c)
0.0
120
JM MPI
HW BBR
1.5
Jet#1
Charged Particles
(|η|<1.0, PT>0.5 GeV/c)
0.0
RDF Preliminary
PT(jet#1) > 30 GeV/c
RDF Preliminary
ETsum Density (GeV)
Charged PTsum Density (GeV/c)
1.0
120
150
180
210
240
270
300
330
360
∆φ (degrees)
¨ (left) Shows the generator level predictions of JIMMY (MPI, PTmin=1.8 GeV/c) and HERWIG (BBR)
for the ∆φ dependence of the charged scalar PTsum density (|η|<1, pT>0.5 GeV/c) relative to the
leading jet for PT(jet#1) > 30 GeV/c.
¨ (right) Shows the generator level predictions of JIMMY (MPI, PTmin=1.8 GeV/c) and HERWIG
(BBR) for the ∆φ dependence of the scalar ETsum density (|η|<1, pT>0 GeV/c) relative to the leading
jet for PT(jet#1) > 30 GeV/c.
¨ The “multiple-parton interaction” (MPI) contribution from JIMMY is about a factor of two larger
than the “Beam-Beam Remnant” (BBR) contribution from HERWIG. The JIMMY program
replaces the HERWIG BBR is its MPI.
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 28
Tuned JIMMY versus
PYTHIA Tune A
Tuned JIMMY produces more
ETsum than PYTHIA Tune A!
ETsum Density: dET/dηdφ
Charged PTsum Density: dPT/dηdφ
RDF Preliminary
generator level
PYA TOT
JM TOT
10.0
100.0
Charged Particles
(|η|<1.0, PT>0.5 GeV/c)
"Transverse"
Region
JM MPI
1.0
10.0
JM MPI
1.0
90
120
150
180
210
240
270
Jet#1
generator level
0.1
60
"Transverse"
Region
RDF Preliminary
0.1
30
PT(jet#1) > 30 GeV
JM 2-to-2
JM ISR
Jet#1
0
All Particles
(|η|<1.0, PT>0 GeV/c)
JM TOT
JM 2-to-2
JM ISR
PYA TOT
PT(jet#1) > 30 GeV/c
ETsum Density (GeV)
Charged PTsum Density (GeV/c)
100.0
300
330
360
0
30
60
90
120
150
180
210
240
270
300
330
360
∆φ (degrees)
∆φ (degrees)
¨ (left) Shows the generator level predictions of PYTHIA Tune A and JIMMY (PTmin=1.8 GeV/c) for
the ∆φ dependence of the charged scalar PTsum density (|η|<1, pT>0.5 GeV/c) relative to the leading
jet with PT(jet#1) > 30 GeV/c. JIMMY and PYTHIA Tune A agree in the “transverse” region..
¨ (right) Shows the generator level predictions of PYTHIA Tune A and JIMMY (PTmin=1.8 GeV/c) for
the ∆φ dependence of the scalar ETsum density (|η|<1, pT>0) relative to the leading jet for PT(jet#1) >
30 GeV/c.
¨ The tuned JIMMY produces a lot more ETsum (pT>0) in the “transverse” region than does
PYTHIA Tune A!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 29
Tuned JIMMY versus
PYTHIA Tune A
Tuned JIMMY produces more
ETsum than PYTHIA Tune A!
ETsum Density: dET/dηdφ
Charged PTsum Density: dPT/dηdφ
RDF Preliminary
generator level
PYA TOT
JM TOT
10.0
100.0
Charged Particles
(|η|<1.0, PT>0.5 GeV/c)
"Transverse"
Region
JM MPI
All Particles
(|η|<1.0, PT>0 GeV/c)
JM TOT
JM 2-to-2
JM ISR
PYA TOT
PT(jet#1) > 30 GeV/c
ETsum Density (GeV)
Charged PTsum Density (GeV/c)
100.0
1.0
PT(jet#1) > 30 GeV
JM 2-to-2
JM ISR
10.0
JM MPI
"Transverse"
Region
1.0
The next step is toRDF
study
Preliminary
the energy in the “transverse
region”. We will have
results of
onPYTHIA
this soon!
¨ (left) Shows the generator level predictions
Tune A and JIMMY (PTmin=1.8 GeV/c) for
Jet#1
Jet#1
generator level
0.1
0.1
0
30
60
90
120
150
180
210
240
270
300
330
360
0
30
60
90
120
150
180
210
240
270
300
330
360
∆φ (degrees)
∆φ (degrees)
the ∆φ dependence of the charged scalar PTsum density (|η|<1, pT>0.5 GeV/c) relative to the leading
jet with PT(jet#1) > 30 GeV/c. JIMMY and PYTHIA Tune A agree in the “transverse” region..
¨ (right) Shows the generator level predictions of PYTHIA Tune A and JIMMY (PTmin=1.8 GeV/c) for
the ∆φ dependence of the scalar ETsum density (|η|<1, pT>0) relative to the leading jet for PT(jet#1) >
30 GeV/c.
¨ The tuned JIMMY produces a lot more ETsum (pT>0) in the “transverse” region than does
PYTHIA Tune A!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 30
Summary
¨ The KT algorithm works fine at the Tevatron and
theory/data (CTEQ61M) look flat!
KT Algorithm
b-jet direction
∆φ
“Toward”
“Away”
¨ We have measured the inclusive b-jet
section, b-bbar jet cross section and
correlations, and everything is as
expected - nothing goofy!
bbar-jet
“Flavor Creation”
Jet #1 Direction
∆φ
“Toward”
b-quark
Initial-State Radiation
Proton
AntiProton
Underlying Event
“Trans 1”
CDF Run 2
Underlying Event
“Trans 2”
“Away”
b-quark
Final-State
Radiation
“Underlying event” important
in jet (and b-jet) production!
¨ We are making good progress in understanding and modeling the
“underlying event”. We now have PYTHIA tune A and JIMMY tune A!
Energy density in the “transverse region” coming soon!
The Tevatron Connection
June 24, 2005
Rick Field - Florida/CDF
Page 31