Northwest Terascale Workshop
Parton Showers and Event Structure at the LHC
Review of the QCD Monte-Carlo Tunes
Rick Field
University of Florida
Outline of Talk
 Review some of what we have learned
University of Oregon February 23, 2009
about “min-bias” and the “underlying
event” in Run 1 at CDF.
Outgoing Parton
PT(hard)
Initial-State Radiation
 Review the various PYTHIA “underlying
Proton
AntiProton
Underlying Event
Underlying Event
event” QCD Monte-Carlo Model tunes.
 Show some things I do not understand
Outgoing Parton
Final-State
Radiation
about the CDF data.
 Show some extrapolations to the LHC.
CMS at the LHC
CDF Run 2
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 1
QCD Monte-Carlo Models:
High Transverse Momentum Jets
Hard Scattering
Initial-State Radiation
Hard Scattering “Jet”
Initial-State Radiation
“Jet”
Outgoing Parton
PT(hard)
Outgoing Parton
PT(hard)
Proton
“Hard Scattering” Component
AntiProton
Final-State Radiation
Outgoing Parton
Underlying Event
Underlying Event
Proton
“Jet”
Final-State Radiation
AntiProton
Underlying Event
Outgoing Parton
Underlying Event
“Underlying Event”
 Start with the perturbative 2-to-2 (or sometimes 2-to-3) parton-parton scattering and add initial and finalstate gluon radiation (in the leading log approximation or modified leading log approximation).
 The “underlying event” consists of the “beam-beam remnants” and from particles arising from soft or
semi-soft multiple parton interactions (MPI).
The “underlying
event” is“jet”
an unavoidable
 Of course the outgoing colored partons fragment
into hadron
and inevitably “underlying event”
background to most collider observables
observables receive contributions from initial
and final-state radiation.
and having good understand of it leads to
more precise collider measurements!
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 2
QCD Monte-Carlo Models:
Lepton-Pair Production
Lepton-Pair
Production
High
PT Z-Boson
Production
Anti-Lepton
Outgoing Parton
Initial-State
Initial-State Radiation
Radiation
High P
T Z-Boson Production
Lepton-Pair
Production
Initial-State
Initial-StateRadiation
Radiation
“Jet”
Proton
Proton
Final-State Radiation
Outgoing
Parton
Anti-Lepton
Final-State Radiation
“Hard Scattering” Component
AntiProton
AntiProton
Underlying Event
Lepton
Z-boson
Underlying Event
Proton
Lepton
Z-boson
AntiProton
Underlying Event
Underlying Event
“Underlying Event”
 Start with the perturbative Drell-Yan muon pair production and add initial-state gluon radiation (in the
leading log approximation or modified leading log approximation).
 The “underlying event” consists of the “beam-beam remnants” and from particles arising from soft or
semi-soft multiple parton interactions (MPI).
 Of course the outgoing colored partons fragment into hadron “jet” and inevitably “underlying event”
observables receive contributions from initial-state radiation.
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 3
Proton-AntiProton Collisions
at the Tevatron
Elastic Scattering
The CDF “Min-Bias” trigger
picks up most of the “hard
core” cross-section plus a
Double
Diffraction
small
amount of single &
double diffraction.
M2
M1
Single Diffraction
M
stot = sEL + sIN
SD +sDD +sHC
1.8 TeV: 78mb
= 18mb
+ 9mb
+ (4-7)mb + (47-44)mb
CDF “Min-Bias” trigger
1 charged particle in forward BBC
AND
1 charged particle in backward BBC
Hard Core
The “hard core” component
contains both “hard” and
“soft” collisions.
“Hard” Hard Core (hard scattering)
Outgoing Parton
“Soft” Hard Core (no hard scattering)
Proton
AntiProton
PT(hard)
Beam-Beam Counters
3.2 < |h| < 5.9
Proton
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
Final-State
Radiation
Outgoing Parton
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 4
Particle Densities
DhD = 4 = 12.6
2

31 charged
charged particles
particle
Charged Particles
pT > 0.5 GeV/c |h| < 1
CDF Run 2 “Min-Bias”
CDF Run 2 “Min-Bias”
Observable
Average
Nchg
Number of Charged Particles
(pT > 0.5 GeV/c, |h| < 1)
3.17 +/- 0.31
0.252 +/- 0.025
PTsum
(GeV/c)
Scalar pT sum of Charged Particles
(pT > 0.5 GeV/c, |h| < 1)
2.97 +/- 0.23
0.236 +/- 0.018
Average Density
per unit h-
dNchg
chg/dhd = 1/4
3/4 = 0.08
0.24
13 GeV/c PTsum
0
-1
h
+1
Divide by 4
dPTsum/dhd = 1/4
3/4 GeV/c = 0.08
0.24 GeV/c
Study the charged particles (pT > 0.5 GeV/c, |h| < 1) and form the charged
particle density, dNchg/dhd, and the charged scalar pT sum density,
dPTsum/dhd.
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 5
CDF Run 1 “Min-Bias” Data
Charged Particle Density
I will talk about “min-bias” and “pile-up” tomorrow!
Charged Particle Density: dN/dhd
Charged Particle Pseudo-Rapidity Distribution: dN/dh
1.0
7
CDF Published
CDF Published
6
0.8
dN/dhd
dN/dh
5
4
3
0.6
0.4
2
0.2
CDF Min-Bias 630 GeV
CDF Min-Bias 1.8 TeV
1
CDF Min-Bias 1.8 TeV
all PT
CDF Min-Bias 630 GeV
all PT
0.0
0
-4
-3
-2
-1
0
1
2
3
4
-4
-3
-1
0
1
2
3
4
Pseudo-Rapidity h
Pseudo-Rapidity h
<dNchg/dh> = 4.2
-2
<dNchg/dhd> = 0.67
 Shows CDF “Min-Bias” data on the number of charged particles per unit pseudo-rapidity
at 630 and 1,800 GeV. There are about 4.2 charged particles per unit h in “Min-Bias”
collisions at 1.8 TeV (|h| < 1, all pT).
DhxD = 1
 Convert to charged particle density, dNchg/dhd, by dividing by 2.
D = 1
There are about 0.67 charged particles per unit h- in “Min-Bias”
0.25
0.67
collisions at 1.8 TeV (|h| < 1, all pT).
 There are about 0.25 charged particles per unit h- in “Min-Bias”
Dh = 1
collisions at 1.96 TeV (|h| < 1, pT > 0.5 GeV/c).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 6
CDF Run 1: Evolution of Charged Jets
“Underlying Event”
Charged Particle D Correlations
PT > 0.5 GeV/c |h| < 1
Charged Jet #1
Direction
“Transverse” region
very sensitive to the
“underlying event”!
Look at the charged
particle density in the
“transverse” region!
2
“Toward-Side” Jet
D
“Toward”
CDF Run 1 Analysis
Away Region
Charged Jet #1
Direction
D
Transverse
Region
“Toward”
“Transverse”

Leading
Jet
“Transverse”
Toward Region
“Transverse”
“Transverse”
Transverse
Region
“Away”
“Away”
Away Region
“Away-Side” Jet
0
-1
h
+1
 Look at charged particle correlations in the azimuthal angle D relative to the leading charged
particle jet.
 Define |D| < 60o as “Toward”, 60o < |D| < 120o as “Transverse”, and |D| > 120o as “Away”.
 All three regions have the same size in h- space, DhxD = 2x120o = 4/3.
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 7
Run 1 Charged Particle Density
“Transverse” pT Distribution
"Transverse" Charged Particle Density: dN/dhd
Charged Particle Density
Charged Particle Jet #1
Direction
"Transverse"
PT(chgjet#1) > 5 GeV/cD
1.0E+00
CDF Min-Bias
CDF Run 1
CDF JET20
data uncorrected
0.75
0.50
Factor of 2!
0.25
1.8 TeV |h|<1.0 PT>0.5 GeV/c
0.00
0
5
10
15
20
25
30
35
40
45
PT(charged jet#1) (GeV/c)
PT(charged jet#1) > 30 GeV/c
“Transverse” <dNchg/dhd> = 0.56
“Min-Bias”
50
Charged Density dN/dhddPT (1/GeV/c)
"Transverse" Charged Density
1.00
CDF Run 1
data uncorrected
1.0E-01
“Toward”
"Transverse"
PT(chgjet#1) > 30 GeV/c
1.0E-02
“Transverse”
“Transverse”
1.0E-03
“Away”
1.0E-04
Min-Bias
1.0E-05
1.8 TeV |h|<1 PT>0.5 GeV/c
1.0E-06
CDF Run 1 Min-Bias data
<dNchg/dhd> = 0.25
0
2
4
6
8
10
12
14
PT(charged) (GeV/c)
 Compares the average “transverse” charge particle density with the average “Min-Bias”
charge particle density (|h|<1, pT>0.5 GeV). Shows how the “transverse” charge particle
density and the Min-Bias charge particle density is distributed in pT.
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 8
ISAJET 7.32
“Transverse” Density
ISAJET uses a naïve leading-log
parton shower-model which does
not agree with the data!
Charged Jet #1
Direction
1.00
D
“Transverse”
“Transverse”
“Away”
CDF Run 1Data
"Transverse" Charged Density
“Toward”
ISAJET
"Transverse" Charged Particle Density: dN/dhd
Isajet
data uncorrected
theory corrected
0.75
"Hard"
0.50
0.25
“Hard”
Component
"Remnants"
1.8 TeV |h|<1.0 PT>0.5 GeV
Beam-Beam
Remnants
0.00
0
5
10
15
20
25
30
35
40
45
50
PT(charged jet#1) (GeV/c)
 Plot shows average “transverse” charge particle density (|h|<1, pT>0.5 GeV) versus PT(charged jet#1)
compared to the QCD hard scattering predictions of ISAJET 7.32 (default parameters with
PT(hard)>3 GeV/c) .
 The predictions of ISAJET are divided into two categories: charged particles that arise from the
break-up of the beam and target (beam-beam remnants); and charged particles that arise from the
outgoing jet plus initial and final-state radiation (hard scattering component).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 9
HERWIG 6.4
“Transverse” Density
D
“Toward”
“Transverse”
“Transverse”
“Away”
1.00
CDF Run 1Data
"Transverse" Charged Density
Charged Jet #1
Direction
HERWIG uses a modified leadinglog parton shower-model which
does agrees better with the data!
"Transverse" Charged Particle Density: dN/dhd
Total
"Hard"
data uncorrected
theory corrected
0.75
0.50
0.25
"Remnants"
Beam-Beam
Remnants
HERWIG
Herwig 6.4 CTEQ5L
PT(hard) > 3 GeV/c
1.8 TeV |h|<1.0 PT>0.5 GeV
0.00
0
5
10
15
20
25
30
PT(charged jet#1) (GeV/c)
35
40
45
50
“Hard”
Component
 Plot shows average “transverse” charge particle density (|h|<1, pT>0.5 GeV) versus PT(charged
jet#1) compared to the QCD hard scattering predictions of HERWIG 5.9 (default parameters with
PT(hard)>3 GeV/c).
 The predictions of HERWIG are divided into two categories: charged particles that arise from the
break-up of the beam and target (beam-beam remnants); and charged particles that arise from the
outgoing jet plus initial and final-state radiation (hard scattering component).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 10
HERWIG 6.4
“Transverse” PT Distribution
HERWIG has the too steep of a pT
dependence of the “beam-beam remnant”
"Transverse" Chargedcomponent
Particle Density:
dN/dhd
of the
“underlying event”!
"Transverse" Charged Particle Density
Charged Jet #1
Direction
CDF Data
"Hard"
Total
data uncorrected
theory corrected
0.75
1.0E+00
Herwig 6.4 CTEQ5L
PT(hard) > 3 GeV/c
D
0.50
0.25
"Remnants"
1.8 TeV |h|<1.0 PT>0.5 GeV
0.00
0
5
10
CDF Data
PT(chgjet#1) > 5 GeV/c
15
20
25
30
35
40
45
PT(charged jet#1) (GeV/c)
Herwig PT(chgjet#1) > 30 GeV/c
“Transverse” <dNchg/dhd> = 0.51
50
Charged Density dN/dhddPT (1/GeV/c)
"Transverse" Charged Density
1.00
data uncorrected
theory corrected
1.0E-01
“Toward”
1.8 TeV |h|<1 PT>0.5 GeV/c
1.0E-02
“Transverse”
1.0E-03
“Transverse”
“Away”
1.0E-04
1.0E-05
PT(chgjet#1) > 30 GeV/c
Herwig 6.4 CTEQ5L
1.0E-06
Herwig PT(chgjet#1) > 5 GeV/c
<dNchg/dhd> = 0.40
0
2
4
6
8
10
12
14
PT(charged) (GeV/c)
 Compares the average “transverse” charge particle density (|h|<1, pT>0.5 GeV) versus
PT(charged jet#1) and the pT distribution of the “transverse” density, dNchg/dhddPT with the
QCD hard scattering predictions of HERWIG 6.4 (default parameters with PT(hard)>3 GeV/c.
Shows how the “transverse” charge particle density is distributed in pT.
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 11
MPI: Multiple Parton
Interactions
“Hard”
Collision
Multiple
Parton
Interaction
outgoing parton
“Hard” Component
“Semi-Hard” MPI
“Soft” Component
AntiProton
Proton
initial-state radiation
initial-state radiation
outgoing parton
final-state radiation
or
+
outgoing jet
final-state radiation
 PYTHIA models the “soft” component of the underlying event
with color string fragmentation, but in addition includes a
contribution arising from multiple parton interactions (MPI) in
which one interaction is hard and the other is “semi-hard”.
Beam-Beam Remnants
color string
color string
 The probability that a hard scattering events also contains a semi-hard multiple parton
interaction can be varied but adjusting the cut-off for the MPI.
 One can also adjust whether the probability of a MPI depends on the PT of the hard
scattering, PT(hard) (constant cross section or varying with impact parameter).
 One can adjust the color connections and flavor of the MPI (singlet or nearest neighbor,
q-qbar or glue-glue).
 Also, one can adjust how the probability of a MPI depends on PT(hard) (single or double
Gaussian matter distribution).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 12
Tuning PYTHIA:
Multiple Parton Interaction Parameters
Parameter
Default
Description
PARP(83)
0.5
Double-Gaussian: Fraction of total hadronic
matter within PARP(84)
PARP(84)
0.2
Double-Gaussian: Fraction of the overall hadron
radius containing the fraction PARP(83) of the
total hadronic matter.
Multiple Parton Interaction
Color String
Color String
PARP(86)
PARP(89)
PARP(90)
PARP(67)
0.33
0.66
1 TeV
0.16
1.0
Probability that the MPI produces two gluons
with color connections to the “nearest neighbors.
Multiple PartonDetermine
Interactionby comparing
with 630 GeV data!
Probability that the MPI produces two gluons
either as described by PARP(85) or as a closed
gluon
loop.
remaining
fraction consists of
Affects
the The
amount
of
quark-antiquark
pairs.
initial-state radiation!
Color String
Hard-Scattering Cut-Off PT0
5
Determines the reference energy E0.
Determines the energy dependence of the cut-off
PT0 as follows PT0(Ecm) = PT0(Ecm/E0)e with
e = PARP(90)
A scale factor that determines the maximum
parton virtuality for space-like showers. The
larger the value of PARP(67) the more initialstate radiation.
PYTHIA 6.206
e = 0.25 (Set A))
4
PT0 (GeV/c)
PARP(85)
Take E0 = 1.8 TeV
3
2
e = 0.16 (default)
1
100
1,000
10,000
100,000
CM Energy W (GeV)
Reference point
at 1.8 TeV
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 13
PYTHIA 6.206 Defaults
MPI constant
probability
scattering
PYTHIA default parameters
6.115
6.125
6.158
6.206
MSTP(81)
1
1
1
1
MSTP(82)
1
1
1
1
PARP(81)
1.4
1.9
1.9
1.9
PARP(82)
1.55
2.1
2.1
1.9
PARP(89)
1,000
1,000
1,000
PARP(90)
0.16
0.16
0.16
4.0
1.0
1.0
PARP(67)
4.0
1.00
"Transverse" Charged Density
Parameter
"Transverse" Charged Particle Density: dN/dhd
CDF Data
Pythia 6.206 (default)
MSTP(82)=1
PARP(81) = 1.9 GeV/c
data uncorrected
theory corrected
0.75
0.50
0.25
1.8 TeV |h|<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)
CTEQ3L
CTEQ4L
CTEQ5L
CDF Min-Bias
CDF JET20
 Plot shows the “Transverse” charged particle density versus PT(chgjet#1) compared to the
QCD hard scattering predictions of PYTHIA 6.206 (PT(hard) > 0) using the default
parameters for multiple parton interactions and CTEQ3L, CTEQ4L, and CTEQ5L.
Note Change
PARP(67) = 4.0 (< 6.138)
PARP(67) = 1.0 (> 6.138)
Oregon Terascale Workshop
February 23, 2009
Default parameters give
very poor description of
the “underlying event”!
Rick Field – Florida/CDF/CMS
Page 14
Run 1 PYTHIA Tune A
CDF Default!
PYTHIA 6.206 CTEQ5L
"Transverse" Charged Particle Density: dN/dhd
Parameter
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
"Transverse" Charged Density
1.00
CDF Preliminary
0.75
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)
Oregon Terascale Workshop
February 23, 2009
Run 1 Analysis
0.50
0.25
CTEQ5L
PYTHIA 6.206 (Set B)
PARP(67)=1
1.8 TeV |h|<1.0 PT>0.5 GeV
0.00
0
PARP(86)
PYTHIA 6.206 (Set A)
PARP(67)=4
data uncorrected
theory corrected
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/CMS
Page 15
Run 1 vs Run 2: “Transverse”
Charged Particle Density
“Transverse” region as
defined by the leading
“charged particle jet”
"Transverse"
"Transverse" Charged
Charged Particle
Particle Density:
Density: dN/dhd
dN/dhd
"Transverse"
Charged
Particle
Density:
dN/dhd
"Transverse"
Charged
Particle
Density:
dN/dhd
Charged Particle Jet #1
Direction
D
“Toward”
“Transverse”
“Transverse”
“Away”
"Transverse"
ChargedDensity
Density
"Transverse"Charged
Charged
Density
"Transverse"
"Transverse"
Charged
Density
1.25
1.25
1.25
CDF Run 1 Min-Bias
CDF Run 1 Min-Bias
CDF
Run
11Published
CDF
Run
JET20
CDF
Run
1 Published
CDF
Run
1 JET20
CDF Run 2 Preliminary
CDF Run 2 Preliminary
PYTHIA Tune A
CDF Run 2
CDFPreliminary
Run 1 Data
CDF
CDF
Preliminary
CDF
Preliminary
data
uncorrected
1.00
1.00
1.00
data
uncorrected
data
uncorrected
data
uncorrected
theory corrected
0.75
0.75
0.75
0.50
0.50
0.50
0.25
0.25
0.25
|h|<1.0
PT>0.5
GeV/c
|h|<1.0
PT>0.5
GeV/c
1.8
TeV
|h|<1.0
|h|<1.0
PT>0.5PT>0.5
GeV GeV
0.00
0.00
0.00
0.00
000
0
10
20
10
10 5 20
20
30
30
10
30
40
50
40
4015 50
50
60
70 2580
60
20
60 70
70 80
80
PT(charged
jet#1)
PT(charged jet#1)
90
10035110
120
140 150
90
130
30
40 130
50
90 100
100 110
110 120
120
13045140
140 150
150
(GeV/c)
PT(charged jet#1) (GeV/c)
(GeV/c)
 Shows the
Excellent agreement
between
Run
1 and 2!
data
on the
average
“transverse” charge particle density (|h|<1, pT>0.5 GeV) as
a function of the transverse momentum of the leading charged particle jet from Run 1.
 Compares the Run 2 data (Min-Bias, JET20, JET50, JET70, JET100) with Run 1. The
errors on the (uncorrected) Run 2 data include both statistical andPYTHIA
correlated
Tune A was tuned to fit
the “underlying event” in Run I!
systematic uncertainties.
 Shows the prediction of PYTHIA Tune A at 1.96 TeV after detector simulation (i.e. after
CDFSIM).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 16
“Towards”, “Away”, “Transverse”
Look at the charged
particle density, the
charged PTsum density
and the ETsum density in
all 3 regions!
D Correlations relative to the leading jet
Jet #1 Direction
“Transverse” region is
very sensitive to the
“underlying event”!
Charged particles pT > 0.5 GeV/c |h| < 1
Calorimeter towers ET > 0.1 GeV |h| < 1
“Toward-Side” Jet
2
Away Region
Z-Boson
Direction
Jet #1 Direction
D
D
Transverse
Region
“Toward”
“Toward”
“Transverse”
“Transverse”
“Away”
“Transverse”
“Transverse”

Leading
Jet
Toward Region
“Away”
Transverse
Region
“Away-Side” Jet
Away Region
0
-1
h
+1
 Look at correlations in the azimuthal angle D relative to the leading charged particle jet (|h| <
1) or the leading calorimeter jet (|h| < 2).
 Define |D| < 60o as “Toward”, 60o < |D| < 120o as “Transverse ”, and |D| > 120o as “Away”.
o
Each of the three regions have area DhD = 2×120 = 4/3.
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 17
Event Topologies
 “Leading Jet” events correspond to the leading
calorimeter jet (MidPoint R = 0.7) in the region |h| < 2
with no other conditions.
 “Inclusive 2-Jet Back-to-Back” events are selected to
have at least two jets with Jet#1 and Jet#2 nearly “backto-back” (D12 > 150o) with almost equal transverse
energies (PT(jet#2)/PT(jet#1) > 0.8) with no other
conditions .
 “Exclusive 2-Jet Back-to-Back” events are selected to
have at least two jets with Jet#1 and Jet#2 nearly “backto-back” (D12 > 150o) with almost equal transverse
energies (PT(jet#2)/PT(jet#1) > 0.8) and PT(jet#3) < 15
GeV/c.
 “Leading ChgJet” events correspond to the leading
charged particle jet (R = 0.7) in the region |h| < 1 with
no other conditions.
 “Z-Boson” events are Drell-Yan events
with 70 < M(lepton-pair) < 110 GeV
with no other conditions.
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Jet #1 Direction
D
“Leading Jet”
“Toward”
“Transverse”
“Transverse”
subset
“Away”
Jet #1 Direction
D
“Inc2J Back-to-Back”
“Toward”
subset
“Transverse”
“Transverse”
“Away”
“Exc2J Back-to-Back”
Jet #2 Direction
ChgJet #1 Direction
D
“Charged Jet”
“Toward”
“Transverse”
“Transverse”
“Away”
Z-Boson Direction
D
“Toward”
Z-Boson
“Transverse”
“Transverse”
“Away”
Page 18
Charged Particle Density D Dependence
Refer to this as a
“Leading Jet” event
Jet #1 Direction
Charged
Particle Density:
Density: dN/dhd
dN/dhd
Charged Particle
D
10.0
10.0
Subset
“Transverse”
“Transverse”
“Away”
Refer to this as a
“Back-to-Back” event
Jet #1 Direction
D
“Toward”
“Transverse”
“Transverse”
Charged Particle
Particle Density
Density
Charged
“Toward”
CDF
CDF Preliminary
Preliminary
30 << ET(jet#1)
ET(jet#1) << 70
70 GeV
GeV
30
Back-to-Back
data
data uncorrected
uncorrected
Leading Jet
Min-Bias
"Transverse"
"Transverse"
Region
Region
1.0
1.0
Jet#1
Jet#1
Charged
Charged Particles
Particles
(|h|<1.0,
(|h|<1.0, PT>0.5
PT>0.5 GeV/c)
GeV/c)
0.1
0.1
00
30
30
60
60
90
120
“Away”
150
180
210
210
240
240
270
270
300
300
330
330
360
360
D (degrees)
Jet #2 Direction
 Look at the “transverse” region as defined by the leading jet (JetClu R = 0.7, |h| < 2) or by the
leading two jets (JetClu R = 0.7, |h| < 2). “Back-to-Back” events are selected to have at least two
jets with Jet#1 and Jet#2 nearly “back-to-back” (D12 > 150o) with almost equal transverse
energies (ET(jet#2)/ET(jet#1) > 0.8) and with ET(jet#3) < 15 GeV.
 Shows the D dependence of the charged particle density, dNchg/dhd, for charged
particles in the range pT > 0.5 GeV/c and |h| < 1 relative to jet#1 (rotated to 270o) for 30
< ET(jet#1) < 70 GeV for “Leading Jet” and “Back-to-Back” events.
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 19
Charged Particle Density D Dependence
“Leading Jet”
Jet #1 Direction
Charged Particle Density: dN/dhd
D
272
CDF Preliminary
“Toward”
252
256
260
264 268
276 280
284
288
292
248
296
244
data uncorrected
30 < ET(jet#1) < 70 GeV
300
240
304
236
308
232
“Transverse”
312
228
“Transverse”
316
224
320
220
324
Jet#1
216
328
212
“Away”
332
208
336
204
340
200
“Back-to-Back”
344
196
348
192
Jet #1 Direction
352
188
D
"Transverse"
Region
184
180
356
"Transverse"
Region
360
4
176
“Toward”
8
172
12
0.5
168
16
164
“Transverse”
“Transverse”
20
160
24
1.0
156
28
Leading Jet
152
“Away”
Back-to-Back
36
148
1.5
144
140
40
44
136
48
132
Jet #2 Direction
52
2.0
128
Polar Plot
32
Charged Particles
(|h|<1.0, PT>0.5 GeV/c)
124
56
60
120
64
116
68
112
108
104
100
96
88
84
80
76
72
92
 Shows the D dependence of the charged particle density, dNchg/dhd, for charged
particles in the range pT > 0.5 GeV/c and |h| < 1 relative to jet#1 (rotated to 270o) for 30
< ET(jet#1) < 70 GeV for “Leading Jet” and “Back-to-Back” events.
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 20
“transMAX” & “transMIN”
Jet #1 Direction
Z-Boson
Direction
Jet #1 Direction
D
Area = 4/6
“transMIN” very sensitive to
the “beam-beam remnants”!
“Toward-Side” Jet
D
“Toward”
“TransMAX”
“Toward”
“TransMIN”
“TransMAX”
“Away”
“TransMIN”
Jet #3
“Away”
“Away-Side” Jet
 Define the MAX and MIN “transverse” regions (“transMAX” and “transMIN”) on an
event-by-event basis with MAX (MIN) having the largest (smallest) density. Each of the
two “transverse” regions have an area in h- space of 4/6.
 The “transMIN” region is very sensitive to the “beam-beam remnant” and the soft
multiple parton interaction components of the “underlying event”.
 The difference, “transDIF” (“transMAX” minus “transMIN”), is very sensitive to the
“hard scattering” component of the “underlying event” (i.e. hard initial and final-state
radiation).
 The overall “transverse” density is the average of the “transMAX” and “transMIN”
densities.
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 21
Observables at the
Particle and Detector Level
“Leading Jet”
Jet #1 Direction
Observable
Particle Level
Detector Level
dNchg/dhd
Number of charged particles
per unit h-
(pT > 0.5 GeV/c, |h| < 1)
Number of “good” charged tracks
per unit h-
(pT > 0.5 GeV/c, |h| < 1)
dPTsum/dhd
Scalar pT sum of charged particles
per unit h-
(pT > 0.5 GeV/c, |h| < 1)
Scalar pT sum of “good” charged tracks per
unit h-
(pT > 0.5 GeV/c, |h| < 1)
<pT>
Average pT of charged particles
(pT > 0.5 GeV/c, |h| < 1)
Average pT of “good” charged tracks
(pT > 0.5 GeV/c, |h| < 1)
PTmax
Maximum pT charged particle
(pT > 0.5 GeV/c, |h| < 1)
Require Nchg ≥ 1
Maximum pT “good” charged tracks
(pT > 0.5 GeV/c, |h| < 1)
Require Nchg ≥ 1
dETsum/dhd
Scalar ET sum of all particles
per unit h-
(all pT, |h| < 1)
Scalar ET sum of all calorimeter towers
per unit h-
(ET > 0.1 GeV, |h| < 1)
PTsum/ETsum
Scalar pT sum of charged particles
(pT > 0.5 GeV/c, |h| < 1)
divided by the scalar ET sum of
all particles (all pT, |h| < 1)
Scalar pT sum of “good” charged tracks
(pT > 0.5 GeV/c, |h| < 1)
divided by the scalar ET sum of
calorimeter towers (ET > 0.1 GeV, |h| < 1)
D
“Toward”
“Transverse”
“Transverse”
“Away”
Jet #1 Direction
D
“Toward”
“Transverse”
“Transverse”
“Away”
Jet #2 Direction
“Back-to-Back”
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 22
CDF Run 1 PT(Z)
PYTHIA
6.2 CTEQ5L
UE Parameters Parameter
Tune A
Tune A25
Tune A50
1
1
1
MSTP(82)
4
4
4
PARP(82)
2.0 GeV
2.0 GeV
2.0 GeV
PARP(83)
0.5
0.5
0.5
PARP(84)
0.4
0.4
0.4
PARP(85)
0.9
0.9
0.9
PARP(86)
0.95
0.95
0.95
PARP(89)
1.8 TeV
1.8 TeV
1.8 TeV
ISR Parameter PARP(90)
0.25
0.25
0.25
PARP(67)
4.0
4.0
4.0
MSTP(91)
1
1
1
PARP(91)
1.0
2.5
5.0
PARP(93)
5.0
15.0
25.0
PT Distribution 1/N dN/dPT
MSTP(81)
s = 1.0
Z-Boson Transverse Momentum
0.12
CDF Run 1 Data
PYTHIA Tune A
PYTHIA Tune A25
PYTHIA Tune A50
s = 2.5
0.08
CDF Run 1
published
1.8 TeV
s = 5.0
Normalized to 1
0.04
0.00
0
2
4
6
8
10
12
14
16
18
Z-Boson PT (GeV/c)
 Shows the Run 1 Z-boson pT distribution
(<pT(Z)> ≈ 11.5 GeV/c) compared with PYTHIA
Tune A (<pT(Z)> = 9.7 GeV/c), Tune A25
(<pT(Z)> = 10.1 GeV/c), and
Tune A50
(<pT(Z)> = 11.2 GeV/c).
Vary the intrensic KT!
Intrensic KT
Oregon Terascale Workshop
February 23, 2009
20
Rick Field – Florida/CDF/CMS
Page 23
CDF Run 1 PT(Z)
Parameter
Tune A
Tune AW
UE Parameters MSTP(81)
1
1
MSTP(82)
4
4
PARP(82)
2.0 GeV
2.0 GeV
PARP(83)
0.5
0.5
PARP(84)
0.4
0.4
PARP(85)
0.9
0.9
PARP(86)
0.95
0.95
PARP(89)
1.8 TeV
1.8 TeV
PARP(90)
0.25
0.25
PARP(62)
1.0
1.25
PARP(64)
1.0
0.2
PARP(67)
4.0
4.0
MSTP(91)
1
1
PARP(91)
1.0
2.1
PARP(93)
5.0
15.0
ISR Parameters
Z-Boson Transverse Momentum
0.12
PT Distribution 1/N dN/dPT
PYTHIA 6.2 CTEQ5L
Tune used by the
CDF-EWK group!
CDF Run 1 Data
PYTHIA Tune A
PYTHIA Tune AW
CDF Run 1
published
0.08
1.8 TeV
Normalized to 1
0.04
0.00
0
2
4
6
8
10
12
14
16
18
Z-Boson PT (GeV/c)
 Shows the Run 1 Z-boson pT distribution (<pT(Z)>
≈ 11.5 GeV/c) compared with PYTHIA Tune A
(<pT(Z)> = 9.7 GeV/c), and PYTHIA Tune AW
(<pT(Z)> = 11.7 GeV/c).
Effective Q cut-off, below which space-like showers are not evolved.
Intrensic KT
The Q2 = kT2 in as for space-like showers is scaled by PARP(64)!
Oregon Terascale Workshop
February 23, 2009
20
Rick Field – Florida/CDF/CMS
Page 24
Jet-Jet Correlations (DØ)
Jet#1-Jet#2 D Distribution
D Jet#1-Jet#2
 MidPoint Cone Algorithm (R = 0.7, fmerge = 0.5)
 L = 150 pb-1 (Phys. Rev. Lett. 94 221801 (2005))
 Data/NLO agreement good. Data/HERWIG agreement
good.
 Data/PYTHIA agreement good provided PARP(67) =
1.0→4.0 (i.e. like Tune A, best fit 2.5).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 25
CDF Run 1 PT(Z)
PYTHIA 6.2 CTEQ5L
Tune DW
Tune AW
UE Parameters 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(62)
1.25
1.25
PARP(64)
0.2
0.2
PARP(67)
2.5
4.0
MSTP(91)
1
1
PARP(91)
2.1
2.1
PARP(93)
15.0
15.0
ISR Parameters
PT Distribution 1/N dN/dPT
Parameter
Z-Boson Transverse Momentum
0.12
CDF Run 1 Data
PYTHIA Tune DW
HERWIG
CDF Run 1
published
0.08
1.8 TeV
Normalized to 1
0.04
0.00
0
2
4
6
8
10
12
14
16
18
20
Z-Boson PT (GeV/c)
 Shows the Run 1 Z-boson pT distribution (<pT(Z)>
≈ 11.5 GeV/c) compared with PYTHIA Tune DW,
and HERWIG.
Tune DW uses D0’s perfered value of PARP(67)!
Intrensic KT
Tune DW has a lower value of PARP(67) and slightly more MPI!
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 26
MIT Search Scheme: Vista/Sleuth
Exclusive 3 Jet Final State Challenge
At least 1 Jet (“trigger” jet)
(PT > 40 GeV/c, |h| < 1.0)
CDF Data
Normalized to 1
PYTHIA
Tune A
Exactly 3 jets
(PT > 20 GeV/c, |h| < 2.5)
R(j2,j3)
Order Jets by PT
Jet1 highest PT, etc.
Bruce Knuteson
Khaldoun
Makhoul
Georgios
Choudalakis
Oregon Terascale Workshop
February 23, 2009
Markus
Klute
Conor
Henderson
Rick Field – Florida/CDF/CMS
Ray
Culbertson
Gene
Flanagan
Page 27
3Jexc R(j2,j3) Normalized
The data have more
3 jet events with
small R(j2,j3)!?
 Let Ntrig40 equal the number of events
Exclusive 3-Jet Production: R(j2,j3)
with at least one jet with PT > 40 geV and
|h| < 1.0 (this is the “offline” trigger).
0.16
 Let N3Jexc20 equal the number of events
0.12
with exactly three jets with PT > 20 GeV/c
and |h| < 2.5 which also have at least one
jet with PT > 40 GeV/c and |h| < 1.0.
 Let N3JexcFr = N3Jexc20/Ntrig40. The is
the fraction of the “offline” trigger events
that are exclusive 3-jet events.
Initial-State Radiation
0.08
Normalized to
N3JexcFr
0.04
0.00
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Underlying Event
 PARP(67) affects the initial-state radiation which
contributes primarily to the region R(j2,j3) > 1.0.
“Jet 3”
Outgoing Parton
Initial-State Radiation
“Jet 2”
R > 1.0
Oregon Terascale Workshop
February 23, 2009
5.0
R(j2,j3)
with PYTHIA Tune AW (PARP(67)=4), Tune DW
(PARP(67)=2.5), Tune BW (PARP(67)=1).
AntiProton
Underlying Event
Data R(j2,j3)
pyAW
pyDW
pyBW
data uncorrected
generator level theory
 The CDF data on dN/dR(j2,j3) at 1.96 TeV compared
Outgoing Parton
“Jet 1”
Proton
dN/dR(j2,j3)
CDF Run 2 Preliminary
Rick Field – Florida/CDF/CMS
Page 28
3Jexc R(j2,j3) Normalized
 Let Ntrig40 equal the number of events
Exclusive
Exclusive 3-Jet
3-Jet Production:
Production: R(j2,j3)
R(j2,j3)
0.16
0.80
0.16
with at least one jet with PT > 40 geV and
|h| < 1.0 (this is the “offline” trigger).
0.12
0.60
0.12
with exactly three jets with PT > 20 GeV/c
0.08
0.40
0.08
and |h| < 2.5 which also have at least one
I do not understand
the
0.04
jet with PT > 40 GeV/c and |h| < 1.0.
0.20
0.04
excess number of events
Normalized to 1
 Let N3JexcFr = N3Jexc20/Ntrig40. The
is R(j2,j3)
with
<
1.0.
0.00
0.00
0.5
1.0
1.5
the fraction of the “offline” trigger
events
0.0related
0.5
1.0
1.5
Perhaps this is0.0
to the
that are exclusive 3-jet events.
“soft energy” problem??
Final-State Radiation
CDF Data
Data
Data R(j2,j3)
R(j2,j3)
hw05
pyDW
pyDW
pyDW
pyDWnoFSR
hw05
pyBW
data
uncorrected
datauncorrected
uncorrected
data
generator
level
theory
generatorlevel
leveltheory
theory
generator
dN/dR(j2,j3)
dN/dR(j2,j3)
dN/dR(j2,j3)
 Let N3Jexc20 equal the number of events
CDF Run
Run 22 Preliminary
Preliminary
CDF
Normalized to
N3JexcFr
2.0
2.0
2.5
2.5
3.0
3.0
3.5
3.5
4.0
4.0
4.5
4.5
5.0
5.0
R(j2,j3)
R(j2,j3)

I will show
youCDF
a lot more
The
data on dN/dR(j2,j3) at 1.96 TeV compared
on Thursday!
with PYTHIA Tune DW (PARP(67)=2.5) and
Outgoing Parton
“Jet 1”
HERWIG (without MPI).
Proton
AntiProton
Underlying Event
Underlying Event
Outgoing Parton
Final-State Radiation
“Jet “Jet
2” 3”
R < 1.0
Oregon Terascale Workshop
February 23, 2009
 Final-State radiation contributes to the region R(j2,j3)
< 1.0.
 If you ignore the normalization and normalize all the
distributions to one then the data prefer Tune BW, but
I believe this is misleading.
Rick Field – Florida/CDF/CMS
Page 29
All use LO as
with L = 192 MeV!
UE Parameters
ISR Parameter
PYTHIA 6.2 Tunes
Parameter
Tune AW
Tune DW
Tune D6
PDF
CTEQ5L
CTEQ5L
CTEQ6L
MSTP(81)
1
1
1
MSTP(82)
4
4
4
PARP(82)
2.0 GeV
1.9 GeV
1.8 GeV
PARP(83)
0.5
0.5
0.5
PARP(84)
0.4
0.4
0.4
PARP(85)
0.9
1.0
1.0
PARP(86)
0.95
1.0
1.0
PARP(89)
1.8 TeV
1.8 TeV
1.8 TeV
PARP(90)
0.25
0.25
0.25
PARP(62)
1.25
1.25
1.25
PARP(64)
0.2
0.2
0.2
PARP(67)
4.0
2.5
2.5
MSTP(91)
1
1
1
PARP(91)
2.1
2.1
2.1
PARP(93)
15.0
15.0
15.0
Uses CTEQ6L
Tune A energy dependence!
Intrinsic KT
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 30
All use LO as
with L = 192 MeV!
UE Parameters
Tune A
ISR Parameter
PYTHIA 6.2 Tunes
Parameter
Tune DWT
Tune D6T
ATLAS
PDF
CTEQ5L
CTEQ6L
CTEQ5L
MSTP(81)
1
1
1
MSTP(82)
4
4
4
PARP(82)
1.9409 GeV
1.8387 GeV
1.8 GeV
PARP(83)
0.5
0.5
0.5
energy dependence!
PARP(84)
0.4
0.4
Tune
B
These
PYTHIA
6.20.5tunes!ATLASTune
Tune
AWare “old”
BW
PARP(85)
1.0
1.0
0.33
There are new 6.4 tunes by
PARP(86)
1.0
1.0
0.66
Arthur
Moraes
(ATLAS)
PARP(89)
1.96 TeV
1.96 TeV
1.0 TeV
Hendrik
Hoeth
(MCnet)
PARP(90)
0.16
0.16
0.16
Peter
Skands
(Tune
S0)
PARP(62)
1.25
1.25
1.0
PARP(64)
0.2
0.2
1.0
PARP(67)
2.5
2.5
1.0
MSTP(91)
1
1
1
PARP(91)
Tune D
PARP(93)
Tune 2.1
DW
15.0
2.1
15.0
5.0
Tune D6T
Intrinsic KT
Oregon Terascale Workshop
February 23, 2009
1.0
Tune D6
Rick Field – Florida/CDF/CMS
Page 31
All use LO as
with L = 192 MeV!
UE Parameters
ISR Parameter
PYTHIA 6.2 Tunes
Parameter
Tune H(6.418)
Tune DWT
Tune D6T
ATLAS
PDF
CTEQ5L
CTEQ5L
CTEQ6L
CTEQ5L
MSTP(81)
1
1
1
1
MSTP(82)
4
4
4
4
PARP(82)
2.1 GeV
1.9409 GeV
1.8387 GeV
1.8 GeV
PARP(83)
0.84
0.5
0.5
0.5
PARP(84)
0.5
0.4
0.4
0.5
PARP(85)
0.82
1.0
1.0
0.33
PARP(86)
0.91
1.0
1.0
0.66
PARP(89)
1.0
1.96 TeV
1.96 TeV
1.0 TeV
PARP(90)
0.17
0.16
0.16
0.16
PARP(62)
2.97
1.25
1.25
1.0
PARP(64)
0.12
0.2
0.2
1.0
PARP(67)
2.74
2.5
2.5
1.0
MSTP(91)
1
1
1
1
PARP(91)
2.0
2.1
2.1
1.0
PARP(93)
5.0
15.0
15.0
5.0
Q2 ordered showers, old MPI!
Intrinsic KT
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 32
JIMMY at CDF
JIMMY
Runs with HERWIG and adds
multiple parton interactions!
PT(JIM)= 2.5 GeV/c.
Jet #1 Direction
JIMMY: MPI
J. M. Butterworth
J. R. Forshaw
M. H. Seymour
D
“Toward”
“Transverse”
PT(JIM)= 3.25 GeV/c.
“Transverse”
"Transverse" ETsum Density: dET/dhd
4.0
"Transverse" ETsum Density (GeV)
The Energy in the “Underlying
Event” in High PT Jet Production
JIMMY was tuned to fit
the energy density in the
“transverse” region for
“leading jet” events!
JIMMY Default
1.96 TeV
HW
3.0
2.0
PY Tune A
JM325
"Leading Jet"
1.0
CDF Run 2 Preliminary
MidPoint R = 0.7 |h(jet)| < 2
The Drell-Yan JIMMY Tune
PTJIM = 3.6 GeV/c,
PT(particle jet#1) (GeV/c)
JMRAD(73) = 1.8
"Transverse" PTsum Density: dPT/dhd
JMRAD(91) = 1.8
generator level theory
All Particles (|h|<1.0)
0.0
0
“Away”
Outgoing Parton
Initial-State Radiation
AntiProton
Underlying Event
Outgoing Parton
Underlying Event
Final-State
Radiation
"Transverse" PTsum Density (GeV/c)
1.6
PT(hard)
Proton
100
200
300
400
500
JIMMY Default
1.96 TeV
1.2
JM325
PY Tune A
0.8
"Leading Jet"
HW
0.4
MidPoint R = 0.7 |h(jet)| < 2
CDF Run 2 Preliminary
generator level theory
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
“Transverse” <Densities> vs PT(jet#1)
Oregon Terascale Workshop
February 23, 2009
0
50
Rick Field – Florida/CDF/CMS
100
150
200
250
300
350
400
450
500
PT(particle jet#1) (GeV/c)
Page 33
Charged Particle Density
HERWIG + JIMMY
Tune
(PTJIM
= 3.6)
Charged
ParticleParticle
Density:Density:
dN/dhd
"Transverse"
Charged
dN/dhdCharged Particle Density:"Away"
Charged
Particle
Density:
dN/dhd
"Away"
dN/dhd
Charged
Particle
Density:
dN/dhd
H. Hoeth, MPI@LHC08
3
CDF Run 2 Preliminary
data corrected
data corrected
generator level theory
pyAW generator level
0.9
2
"Drell-Yan Production"
70 < M(pair) < 110 GeV
0.6
1
20
20
40
60
generator level theory
2
40
80
100
0
60
120
0
"Drell-Yan Production"
70 < M(pair) < 110 GeV
80
160
20
140
180
PT(Z-Boson)
(GeV/c)(GeV/c)
PT(jet#1)
or PT(Z-Boson)
Z-Boson Direction
D
High PT Z-Boson Production
CDF
CDFRun
Run22Preliminary
Preliminary
100
200
40
"Leading Jet"
data
datacorrected
corrected
pyA generator
generator
levellevel
theory
pyAW
Charged Particles
Particles (|h|<1.0,
(|h|<1.0, PT>0.5
PT>0.5
GeV/c)
HW
Charged
GeV/c)
excluding the lepton-pair
"Toward"
0
0.0
00
"Leading
Jet"
"Away" data corrected
1
"Transverse"
"Z-Boson"
0.3
44
Average
Density
"Away" Charged
Charged Density
CDFRun
Run22Preliminary
Preliminary
CDF
"Away" Charged Density
"Transverse"
ChargedDensity
Density
Average Charged
3
1.2
33
"Away"
"Toward"
22
JIM
11
"Leading Jet"
MidPoint R=0.7 |h(jet#1)|<2
"Z-Boson""Transverse"
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
00
00
60
20
20
40
40
60
60
80
80
80
100
100
100
120
120
140
140
Jet #1 Direction
“Transverse”
PT(hard)
“Toward”
AntiProton
“Transverse”
“Transverse”
200
200
Outgoing Parton
D
Initial-State Radiation
“Toward”
Proton
180
180
PT(jet#1)
or PT(Z-Boson)
PT(jet#1)
(GeV/c) (GeV/c)
PT(Z-Boson) (GeV/c)
Outgoing Parton
160
160
“Transverse”
Initial-State Radiation
Proton
AntiProton
Underlying Event
Underlying Event
“Away”
“Away”
Outgoing Parton
Z-boson
Final-State
Radiation
 Data at 1.96 TeV on the density of charged particles, dN/dhd, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson”
and “Leading Jet” events as a function of the leading jet pT or PT(Z) 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 AW and Tune A, respectively, at the
particle level (i.e. generator level).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 34
The “Transverse” Region
“Leading Jet”
Jet #1 Direction
D
“Toward”
“Transverse”
“Transverse”
“Away”
Data - Theory
(GeV) (GeV)
"Transverse"
ETsum Density
5.0
1.6
0.4Density:
density corresponds
"Transverse" ETsum
dET/dhdto
1.67 GeV in the
CDF CDF
Run Run
2 Preliminary
2 Preliminary “transverse”
"Leading
Jet"
region!
data corrected
data corrected
generator
level theory
generator
level theory
4.0
1.2
MidPoint R=0.7 |h(jet#1)|<2
Stable Particles (|h|<1.0, all PT)
HW
3.0
0.8
PY Tune A
2.0
0.4
PY Tune A
1.0
0.0
"Leading Jet"
MidPoint R=0.7 |h(jet#1)|<2
HW
Stable Particles (|h|<1.0, all PT)
0.0
-0.4
00
50
50
100
100
150
150
200
250
300
350
400
PT(jet#1) (GeV/c)

1.96
TeV- on
the scalar
ETscalar
sum density,
with |h| <with
1 for
jet” events
a function
 Data
Showsatthe
Data
Theory
for the
ET sum dET/dhd,
density, dET/dhd,
|h|“leading
< 1 for “leading
jet”asevents
as a
of
the leading
pT forjet
thep“transverse”
region. The data are corrected to the particle level (with errors that
function
of thejet
leading
T for the “transverse” region for PYTHIA Tune A and HERWIG (without MPI).
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).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 35
The “TransMAX/MIN” Regions
“Leading Jet”
Jet #1 Direction
D
“Toward”
“TransMAX”
“TransMIN”
“Away”
"TransMAX"
Density
(GeV)
"Transverse"
Density
(GeV)
TransMAX ETsum
-ETsum
TransMIN
(GeV)
"TransveMIN"
ETsum
Density
(GeV)
"TransMAX"
"TransMIN"
ETsum
Density:
dET/dhd
"TransMAX/MIN"
ETsum
Density:
dET/dhd
"TransDIF" ETsum
Density:
dET/dhd
6.0
3.0
6.0
5.0
CDF
"Leading Jet"
CDF Run
Run 22 Preliminary
Preliminary
CDF
Run
4.0
4.0
2.0
4.0
3.0
PY Tune A
2.0
2.0
1.0
2.0
HW
data corrected
generator level theory
HW
PY
PYTune
TuneAA
"Leading Jet"
MidPoint R=0.7 |h(jet#1)|<2
"Leading Jet"
"transMIN"
Jet"
MidPoint "Leading
R=0.7 |h(jet#1)|<2
MidPoint
R=0.7 |h(jet#1)|<2
PY Tune
A
Stable Particles (|h|<1.0, all PT)
Stable
Particles
(|h|<1.0,
all PT)
Stable
Particles
(|h|<1.0,
all PT)
HW
1.0
HW
0.0
0.0
0.0
0.0
CDF Run 2 Preliminary
data
MidPoint R=0.7 |h(jet#1)|<2
datacorrected
corrected
data
corrected
"transMAX"
generator
theory
generatorlevel
level
theory
generator
level
theory
Stable
Particles (|h|<1.0, all PT)
000
50
50
50
100
100
100
150
150
150
200
200
200
250
250
250
250
300
300
300
300
350
350
350
350
400
400
400
400
PT(jet#1)
PT(jet#1) (GeV/c)
(GeV/c)
PT(jet#1)
(GeV/c)

 Data
Data at
at 1.96
1.96 TeV
TeV on
on the
the scalar
scalar E
ETTT sum
sum density,
density, dET/dhd,
dET/dhd, with
with |h|
|h| <
< 11 for
for “leading
“leading jet”
jet” events
events as
as aa function
function of
of
of
leading
“transMAX”
region.
corrected
to the
particle
(with
errors
the
leading
jet
ppT pfor
thethe
“transMIN”
region.
TheThe
datadata
are are
corrected
to the
particle
levellevel
(with
errors
thatthat
T for
thethe
leading
jetjet
T for “transDIF” = “transMAX”-”transMIN. The data are corrected to the particle level (with
include
both
the statistical
and the
systematic
and are compared
PYTHIA
A and
errors that
include
both theerror
statistical
error
and the uncertainty)
systematic uncertainty)
and are with
compared
withTune
PYTHIA
HERWIG
MPI)
at the MPI)
particle
levelparticle
(i.e. generator
Tune A and(without
HERWIG
(without
at the
level (i.e.level).
generator level).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 36
The Leading Jet Mass
“Leading Jet”
Leading Jet Invariant
Off by ~2Mass
GeV
12.0
70
“Toward”
“Transverse”
“Transverse”
“Away”
Data
Theory
(GeV)
Jet-Mass
(GeV)
Jet #1 Direction
D
CDF
CDFRun
Run22Preliminary
Preliminary
60
"Leading Jet"
MidPoint R=0.7 |h(jet#1)|<2
data
datacorrected
corrected
generator
generatorlevel
leveltheory
theory
8.0
50
HW
PY Tune A
40
4.0
30
PY Tune A
20
0.0
10
-4.0
0
00
"Leading Jet"
MidPoint R=0.7 |h(jet#1)|<2
HW
5050
100
100
150
150
200
200
250
250
300
300
350
400
PT(jet#1
uncorrected)
PT(jet#1)
(GeV/c)(GeV/c)

atthe
1.96
TeV- on
the leading
invariant
mass for mass
“leading
jet” events
asevents
a function
of the leading
pT
 Data
Shows
Data
Theory
for thejet
leading
jet invariant
for “leading
jet”
as a function
of thejet
leading
for
“transverse” region. The data are corrected to the particle level (with errors that include both the
jet pthe
T for the “transverse” region for PYTHIA Tune A and HERWIG (without MPI).
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).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 37
The “Underlying Event” in
High PT Jet Production (LHC)
High PT Jet Production
Outgoing Parton
PT(hard)
Initial-State
Radiation
The “Underlying Event” Proton
Underlying Event
Underlying Event
“Underlying event” much
more active at the LHC!
Final-State
Radiation
Outgoing Parton
"Transverse" Charged Particle Density: dN/dhd
"Transverse" Charged Particle Density: dN/dhd
1.0
2.0
RDF Preliminary
LHC
RDF Preliminary
generator level
0.8
0.6
PY Tune AW
HERWIG
0.4
1.96 TeV
0.2
"Leading Jet"
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
"Transverse" Charged Density
"Transverse" Charged Density
Charged particle density
versus PT(jet#1)
AntiProton
generator level
1.5
PY Tune AW
HERWIG
1.0
CDF
0.5
"Leading Jet"
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
0
50
100
150
200
250
300
350
400
450
500
0
250
500
PT(particle jet#1) (GeV/c)
750
1000
1250
1500
1750
2000
2250
2500
PT(particle jet#1) (GeV/c)
 Charged particle density in the “Transverse”  Charged particle density in the “Transverse”
region versus PT(jet#1) at 1.96 TeV for PY
region versus PT(jet#1) at 14 TeV for PY Tune
Tune AW and HERWIG (without MPI).
AW and HERWIG (without MPI).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 38
Drell-Yan Production (Run 2 vs LHC)
Drell-Yan Production
Proton
<pT(m+m-)> is much
larger at the LHC!
Lepton-Pair Transverse
Momentum
Lepton
AntiProton
Underlying Event
Underlying Event
Shapes of the pT(m+m-)
distribution at the Z-boson mass.
Initial-State
Radiation
Anti-Lepton
Lepton-Pair Transverse Momentum
Drell-Yan PT(m+m-) Distribution
80
0.10
Drell-Yan
Drell-Yan
LHC
60
1/N dN/dPT (1/GeV)
Average Pair PT
generator level
40
Tevatron Run 2
20
0
0.08
PY Tune DW (solid)
HERWIG (dashed)
0.06
70 < M(m-pair) < 110 GeV
|h(m-pair)| < 6
0.04
0.02
PY Tune DW (solid)
HERWIG (dashed)
Z
generator level
Tevatron Run2
LHC
Normalized to 1
0.00
0
100
200
300
400
500
600
700
800
900
1000
0
5
Lepton-Pair Invariant Mass (GeV)
10
15
20
25
30
35
40
PT(m+m-) (GeV/c)
 Average Lepton-Pair transverse momentum  Shape of the Lepton-Pair pT distribution at the
Z-boson mass at the Tevatron and the LHC for
at the Tevatron and the LHC for PYTHIA
PYTHIA Tune DW and HERWIG (without MPI).
Tune DW and HERWIG (without MPI).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 39
The “Underlying Event” in
Drell-Yan Production
Drell-Yan Production
The “Underlying Event”
Lepton
Proton
HERWIG (without MPI)
is much less active than
PY Tune AW (with MPI)!
Underlying Event
Charged particle density
versus M(pair)
AntiProton
Underlying Event
“Underlying event” much
more active at the LHC!
Initial-State
Radiation
Anti-Lepton
Charged Particle Density: dN/dhd
Charged Particle Density: dN/dhd
1.5
1.0
RDF Preliminary
generator level
PY Tune AW
0.8
0.6
0.4
HERWIG
0.2
Drell-Yan
1.96 TeV
Z
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
(excluding lepton-pair )
Charged Particle Density
Charged Particle Density
RDF Preliminary
generator level
Z
LHC
1.0
PY Tune AW
CDF
0.5
Drell-Yan
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
(excluding lepton-pair )
HERWIG
0.0
0.0
0
50
100
150
200
250
0
50
100
150
200
250
Lepton-Pair Invariant Mass (GeV)
Lepton-Pair Invariant Mass (GeV)
 Charged particle density versus the lepton-  Charged particle density versus the lepton-pair
invariant mass at 14 TeV for PYTHIA Tune AW
pair invariant mass at 1.96 TeV for PYTHIA
and HERWIG (without MPI).
Tune AW and HERWIG (without MPI).
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 40
Summary
 We are making good progress in modeling “min-bias”
collisions! I will talk more about this tomorrow.
 We are making good progress in understanding and
modeling the “underlying event” high transverse
momentum jet production and in Drell-Yan production.
I will talk much more about this tomorrow.
“Minumum Bias” Collisions
Proton
AntiProton
Outgoing Parton
PT(hard)
Initial-State Radiation
Proton
AntiProton
Underlying Event
 There are still some things we do not fully understand!
Outgoing Parton
** Soft Underlying Event Energy **
Underlying Event
Final-State
Radiation
** Jet Mass **
Drell-Yan Production
** R(J2,J3) **
Proton
Lepton
AntiProton
Underlying Event
Underlying Event
I will talk much more
about this on Thursday!
Anti-Lepton
AND we really do not know how to
extrapolate to the LHC!
Oregon Terascale Workshop
February 23, 2009
Rick Field – Florida/CDF/CMS
Page 41