XIII International Workshop
on Deep Inelastic Scattering
Hadronic Final States Working Group
Multiple Parton Interactions
Outgoing Parton
PT(hard)
Proton
AntiProton
Underlying Event
Rick Field
University of Florida
(for the CDF Collaboration)
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Underlying Event
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.
¨ Understanding and Modeling the
“Underlying Event” in Run 2 at CDF.
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 2
The TeVatron
~800 pb-1 delivered
More than four
times Run 1!
CDF has ~600 pb-1 on tape!
The TeVatron delivered more than 350 pb-1 in 2004!
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 3
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: Jet Clu, 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.
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Important for the LHC!
Page 4
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”!
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 5
Cone Algorithms
¨
CDF JetClu Cone Algorithm:
ƒ
ƒ
ƒ
ƒ
ƒ
¨
MidPoint Cone Algorithm:
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
DIS2005
April 28, 2005
Detector dependent algorithm (CDF Run 1 legacy)!
Cluster together calorimeter towers by their “angular”
proximity in (η, φ) space.
Merged if common ET is more than 75% of smallest jet.
Not infrared safe at the parton level.
To compare with NLO at the parton level one must introduce
and ad hoc parameter Rsep (R’=Rsep×R).
Define a list of seeds using CAL towers with ET > 1 GeV.
Also put seed in a the midpoint (η-φ) for each pair of proto-jets
separated by less than 2R and iterate for stable jets.
Merging/Splitting (fmerge = 50%, 70%).
Results in improved infrared stability and can be compared
with NLO parton-level calculations, but still needs the ad hoc
Rsep parameter.
Not all towers end up in a “jet”.
Use two R values (R/2 for finding stable cones, R for calculating
jet properties).
Rick Field - Florida/CDF
Page 6
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
DIS2005
April 28, 2005
Final-State
Radiation
Only towers with ET > 0.5 GeV are shown
Rick Field - Florida/CDF
Page 7
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
DIS2005
April 28, 2005
Underlying Event
Final-State
Radiation
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 8
Jet Corrections
Theory
Experiment
I believe we should correct the
data back to what we measure
(i.e. the hadron 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 hadron 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
DIS2005
April 28, 2005
Underlying Event
Final-State
Radiation
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 9
Data at the “hadron level”!
KT Jet Cross-Section
NLO parton level theory
corrected to the “hadron level”!
Correction factors
applied to NLO theory!
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 10
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!
(see the talk by Regis Lefèvre)
Correction factors
applied to NLO theory!
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 11
The b-Jet Cross-Section
Construct the invariant mass
of particles pointing back to
the secondary vertex!
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).
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 12
The b-Jet Cross-Section
“Flavor Creation”
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!
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 13
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”.
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 14
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).
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 15
Tuned PYTHIA 6.206
Double Gaussian
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
CDF Run 2 default
DIS2005
April 28, 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)).
Rick Field - Florida/CDF
Page 16
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.
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 17
“TransMIN” PTsum Density
versus ET(jet#1)
“Leading Jet”
Jet #1 Direction
"MIN Transverse" PTsum Density: dPT/dηdφ
∆φ
“Toward”
“TransMAX”
“TransMIN”
“Away”
“Back-to-Back”
Jet #1 Direction
∆φ
“Toward”
“TransMAX”
“TransMIN”
“Away”
Jet #2 Direction
"Transverse" PTsum Density (GeV/c)
0.6
CDF Run 2 Preliminary
1.96 TeV
data uncorrected
theory + CDFSIM
0.4
Leading Jet
PY Tune A
0.2
Back-to-Back
HW
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
0
50
“transMIN” is very sensitive to the
“beam-beam remnant” component
of the “underlying event”!
100
150
200
250
ET(jet#1) (GeV)
¨ Use the leading jet to define the MAX and MIN “transverse” regions on an event-byevent basis with MAX (MIN) having the largest (smallest) charged PTsum density.
¨ Shows the “transMIN” charged PTsum density, dPTsum/dηdφ, for pT > 0.5 GeV/c, |η| < 1
versus ET(jet#1) for “Leading Jet” and “Back-to-Back” events.
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 18
“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.
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 19
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)
DIS2005
April 28, 2005
60
Rick Field - Florida/CDF
Page 20
Tuned JIMMY versus
PYTHIA Tune A
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)
PY Tune A
Charged PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
100.0
Leading Jet
10.0
1.0
CDF Preliminary
0.1
0
30
60
90
Jet#1
"Transverse"
Region
data uncorrected
theory + CDFSIM
JIMMY tuned to agree
with PYTHIA Tune A!
RDF Preliminary
generator level
PYA TOT
JM TOT
10.0
Charged Particles
(|η|<1.0, PT>0.5 GeV/c)
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.
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 21
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.
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 22
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!
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 23
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!
DIS2005
April 28, 2005
Rick Field - Florida/CDF
Page 24