University of Glasgow
Tevatron Energy Scan:
Findings & Surprises
Rick Field
University of Florida
Outline of Talk
 Simulating hadron-hadron collisions: The
early days of Feynman-Field
Phenomenology.
Outgoing Parton
PT(hard)
 The CDF QCD Monte-Carlo Model tunes.
Initial-State Radiation
Proton
AntiProton
Underlying Event
Underlying Event
 The CMS QCD Monte-Carlo Model tunes.
Outgoing Parton
 New CDF data from the Tevatron Energy
Final-State
Radiation
Scan.
 Mapping out the energy dependence:
Tevatron to the LHC.
 Summary & Conclusions.
University of Glasgow Colloquium
October 16, 2013
CDF Run 2
300 GeV, 900 GeV, 1.96 TeV
Rick Field – Florida/CDF/CMS
CMS at the LHC
900 GeV, 7 & 8 TeV
Page 1
Toward an Understanding of
Hadron-Hadron Collisions
Feynman-Field Phenomenology1
Feynman
 From 7 GeV/c
and
st
hat!
Field
Outgoing Parton
p0’s
to 1 TeV Jets.
The early days of trying to
understand and simulate
hadron-hadron collisions.
PT(hard)
Initial-State Radiation
Proton
AntiProton
Underlying Event
Outgoing Parton
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Underlying Event
Final-State
Radiation
Page 2
The Feynman-Field Days
1973-1983
“Feynman-Field
Jet Model”
 FF1: “Quark Elastic Scattering as a Source of High Transverse Momentum
Mesons”, R. D. Field and R. P. Feynman, Phys. Rev. D15, 2590-2616 (1977).
 FFF1: “Correlations Among Particles and Jets Produced with Large Transverse
Momenta”, R. P. Feynman, R. D. Field and G. C. Fox, Nucl. Phys. B128, 1-65
(1977).
 FF2: “A Parameterization of the properties of Quark Jets”, R. D. Field and R. P.
Feynman, Nucl. Phys. B136, 1-76 (1978).
 F1: “Can Existing High Transverse Momentum Hadron Experiments be
Interpreted by Contemporary Quantum Chromodynamics Ideas?”, R. D. Field,
Phys. Rev. Letters 40, 997-1000 (1978).
 FFF2: “A Quantum Chromodynamic Approach for the Large Transverse
Momentum Production of Particles and Jets”, R. P. Feynman, R. D. Field and G.
C. Fox, Phys. Rev. D18, 3320-3343 (1978).
 FW1: “A QCD Model for e+e- Annihilation”, R. D. Field and S. Wolfram, Nucl.
Phys. B213, 65-84 (1983).
My 1st graduate
student!
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 3
Hadron-Hadron Collisions
FF1 1977
 What happens when two hadrons
collide at high energy?
Hadron
Hadron
Feynman quote from FF1
???
“The model we shall choose is not a popular one,
 Most of the time the hadrons
ooze
so that we will not duplicate too much of the
through each other andwork
fall apart
(i.e.who are similarly analyzing
of others
no hard scattering). The
outgoing
various
models (e.g. constituent interchange
particles continue in roughly
the same
model, multiperipheral
models, etc.). We shall
Parton-Parton Scattering Outgoing Parton
assume
direction as initial proton
andthat the high PT particles arise from
“Soft” constituent
Collision (no large transverse momentum)
direct hard collisions between
antiproton.
quarks in the incoming particles, which
Hadron
Hadron
 Occasionally there will
be a large
fragment
or cascade down
into several hadrons.”
transverse momentum meson.
Question: Where did it come from?
 We assumed it came from quark-quark
elastic scattering, but we did not know
how to calculate it!
Outgoing Parton
high PT meson
“Black-Box Model”
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 4
Quark-Quark Black-Box Model
No gluons!
Quark Distribution Functions
determined from deep-inelastic
lepton-hadron collisions
FF1 1977
Feynman quote from FF1
“Because of the incomplete knowledge of
our functions some things can be predicted
with more certainty than others. Those
experimental results that are not well
predicted can be “used up” to determine
these functions in greater detail to permit
better predictions of further experiments.
Our papers will be a bit long because we
wish to discuss this interplay in detail.”
Quark-Quark Cross-Section
Unknown! Deteremined from
hadron-hadron collisions.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Quark Fragmentation Functions
determined from e+e- annihilations
Page 5
Quark-Quark Black-Box Model
Predict
particle ratios
FF1 1977
Predict
increase with increasing
CM energy W
“Beam-Beam
Remnants”
Predict
overall event topology
(FFF1 paper 1977)
7 GeV/c p0’s!
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 6
Telagram from Feynman
July 1976
SAW CRONIN AM NOW CONVINCED WERE RIGHT TRACK QUICK WRITE
FEYNMAN
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 7
QCD Approach: Quarks & Gluons
Quark & Gluon Fragmentation
Functions
Q2 dependence predicted from QCD
Parton Distribution Functions
Q2 dependence predicted from
QCD
FFF2 1978
Feynman quote from FFF2
“We investigate whether the present
experimental behavior of mesons with
large transverse momentum in hadron-hadron
collisions is consistent with the theory of
quantum-chromodynamics (QCD) with
asymptotic freedom, at least as the theory
is now partially understood.”
Quark & Gluon Cross-Sections
Calculated from QCD
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 8
Feynman Talk at Coral Gables
(December 1976)
1st transparency
Last transparency
“Feynman-Field
Jet Model”
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 9
A Parameterization of
the Properties of Jets
Field-Feynman 1978
Secondary Mesons
(after decay)
continue
 Assumed that jets could be analyzed on a “recursive”
principle.
(bk) (ka)
 Let f(h)dh be the probability that the rank 1 meson leaves
fractional momentum h to the remaining cascade, leaving
Rank 2
Rank 1
quark “b” with momentum P1 = h1P0.
 Assume that the mesons originating from quark “b” are
distributed in presisely the same way as the mesons which
(cb)
(ba)
Primary Mesons
came from quark a (i.e. same function f(h)), leaving
quark “c” with momentum P2 = h2P1 = h2h1P0.
cc pair bb pair
Calculate F(z)
from f(h) and b i!
Original quark with
flavor “a” and
momentum P0
University of Glasgow Colloquium
October 16, 2013
 Add in flavor dependence by letting bu = probabliity of
producing u-ubar pair, bd = probability of producing ddbar pair, etc.
 Let F(z)dz be the probability of finding a meson
(independent of rank) with fractional mementum z of the
original quark “a” within the jet.
Rick Field – Florida/CDF/CMS
Page 10
Monte-Carlo Simulation
of Hadron-Hadron Collisions
FF1-FFF1 (1977)
“Black-Box” Model
F1-FFF2 (1978)
QCD Approach
FFFW “FieldJet” (1980)
QCD “leading-log order” simulation
of hadron-hadron collisions
the past
yesterday
today
FF2 (1978)
Monte-Carlo
simulation of “jets”
ISAJET
HERWIG
(“FF” Fragmentation)
(“FW” Fragmentation)
SHERPA
PYTHIA 8
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
“FF” or “FW”
Fragmentation
PYTHIA 6.4
HERWIG++
Page 11
High PT Jets
CDF (2006)
Feynman, Field, & Fox (1978)
Predict
large “jet”
cross-section
30 GeV/c!
Feynman quote from FFF
600writing,
GeV/c Jets!
“At the time of this
there is
still no sharp quantitative test of QCD.
An important test will come in connection
with the phenomena of high PT discussed here.”
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 12
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!
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 13
Proton-Proton Collisions
Elastic Scattering
Single Diffraction
Double Diffraction
M2
M
M1
stot = sEL + sSD
IN +sDD +sHC
ND
“Inelastic Non-Diffractive Component”
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
PT(hard)
Proton
Proton
Proton
Underlying Event
Underlying Event
Initial-State
Radiation
Final-State
Radiation
Outgoing Parton
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 14
The Inelastic Non-Diffractive
Cross-Section
Occasionally one of
the parton-parton
collisions is hard
(pT > ≈2 GeV/c)
Proton
Proton
Majority of “minbias” events!
Proton
“Semi-hard” partonparton collision
(pT < ≈2 GeV/c)
Proton
+
Proton
+
Proton
Proton
Proton
+
Proton
Proton
+…
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Multiple-parton
interactions (MPI)!
Page 15
The “Underlying Event”
Select inelastic non-diffractive events
that contain a hard scattering
Proton
Hard parton-parton
collisions is hard
(pT > ≈2 GeV/c)
Proton
1/(pT)4→ 1/(pT2+pT02)2
The “underlying-event” (UE)!
Proton
Given that you have one hard
scattering it is more probable to
have MPI! Hence, the UE has
more activity than “min-bias”.
University of Glasgow Colloquium
October 16, 2013
Proton
+
+
Proton
Proton
Rick Field – Florida/CDF/CMS
“Semi-hard” partonparton collision
(pT < ≈2 GeV/c)
Proton
Proton
+…
Multiple-parton
interactions (MPI)!
Page 16
Allow leading hard
scattering to go to
zero pT with same
cut-off as the MPI!
Model of sND
Proton
Proton
Proton
Proton
Proton
+
Proton
“Semi-hard” partonparton collision
(pT < ≈2 GeV/c)
1/(pT)4→ 1/(pT2+pT02)2
Model of the inelastic nondiffractive cross section!
+
Proton
Proton
Proton
+
Proton
Proton
+…
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Multiple-parton
interactions (MPI)!
Page 17
UE Tunes
Allow primary hard-scattering to
go to pT = 0 with same cut-off!
“Underlying Event”
Fit the “underlying
event” in a hard
scattering process.
Proton
Proton
1/(pT)4→ 1/(pT2+pT02)2
“Min-Bias”
“Min-Bias” (add
(ND)single & double diffraction)
Proton
Predict MB (ND)!
Proton
+
+
Proton
Proton
Proton
Single Diffraction
Predict MB (IN)!
+…
University of Glasgow Colloquium
October 16, 2013
Proton
+
Proton
Proton
Double Diffraction
M2
M
Rick Field – Florida/CDF/CMS
M1
Page 18
Tuning PYTHIA 6.2:
Multiple Parton Interaction Parameters
Parameter
Default
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.
Determines the energy
Probability
that of
thethe
MPI
produces two gluons
dependence
MPI!
with color connections to the “nearest neighbors.
0.33
PARP(86)
0.66
PARP(89)
PARP(82)
PARP(90)
PARP(67)
1 TeV
1.9
GeV/c
0.16
1.0
Multiple Parton Interaction
Color String
Color String
Remember the energy dependence
Multiple PartonDetermine
Interactionby comparing
with 630 GeV data!
of the “underlying event”
activity depends on both the
Determines the reference energy E .
e = PARP(90) and the PDF!
Probability thatAffects
the MPI
theproduces
amount two
of gluons
either as described
by PARP(85)
or as a closed
initial-state
radiation!
gluon loop. The remaining fraction consists of
quark-antiquark pairs.
Color String
Hard-Scattering Cut-Off PT0
0
The cut-off PT0 that regulates the 2-to-2
scattering divergence 1/PT4→1/(PT2+PT02)2
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.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
5
PYTHIA 6.206
e = 0.25 (Set A))
4
PT0 (GeV/c)
PARP(85)
Description
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
Page 19
Collider Coordinates
xz-plane
x-axis
x-axis
Beam Axis
Proton
P
cm
AntiProton
z-axis
Proton
“Transverse”
xy-plane
y-axis
AntiProton z-axis
 cm is the center-of-mass scattering angle and  is the
azimuthal angle. The “transverse” momentum of a
particle is given by PT = P cos(cm).
 Use h and  to determine the direction of an
outgoing particle, where h is the “pseudo-rapidity”
defined by h = -log(tan(cm/2)).
Rick Field – Florida/CDF/CMS
Azimuthal
Scattering Angle
y-axis
 The z-axis is defined to be the beam axis with
the xy-plane being the “transverse” plane.
University of Glasgow Colloquium
October 16, 2013
Center-of-Mass
Scattering Angle
PT

x-axis
h
cm
0
90o
1
40o
2
15o
3
6o
4
2o
Page 20
Traditional Approach
CDF Run 1 Analysis Charged Particle D Correlations
Leading Calorimeter Jet or
Charged Jet #1
Leading Charged Particle Jet or
PT > PTmin |h| < hcut
Direction
Leading Charged Particle or
2p
“Transverse” region
very sensitive to the
“underlying event”!
Away RegionZ-Boson
“Toward-Side” Jet
D
“Toward”
“Transverse”
“Transverse”
“Away”
Leading Object
Direction
D
“Toward”
“Transverse”
“Transverse”
Transverse
Region

Leading
Object
Toward Region
Transverse
Region
“Away”
Away Region
0
-hcut
“Away-Side” Jet
h
+hcut
 Look at charged particle correlations in the azimuthal angle D relative to a leading object (i.e.
CaloJet#1, ChgJet#1, PTmax, Z-boson). For CDF PTmin = 0.5 GeV/c hcut = 1.
 Define |D| < 60o as “Toward”, 60o < |D| < 120o as “Transverse”, and |D| > 120o as

“Away”.
o
All three regions have the same area in h- space, Dh×D = 2hcut×120 = 2hcut×2p/3. Construct
densities by dividing by the area in h- space.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 21
Particle Densities
DhD = 4p = 12.6
2p

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 = 1/4p
3/4p = 0.08
0.24
13 GeV/c PTsum
0
-1
h
+1
Divide by 4p
dPTsum/dhd = 1/4p
3/4p 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.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 22
UE Observables
 “Transverse” Charged Particle Density: Number of charged
particles (pT > 0.5 GeV/c, |h| < hcut) in the “transverse” region as
defined by the leading charged particle, PTmax, divided by the
area in h- space, 2hcut×2p/3, averaged over all events with at least
one particle with pT > 0.5 GeV/c, |h| < hcut.
 “Transverse” Charged PTsum Density: Scalar pT sum of the
charged particles (pT > 0.5 GeV/c, |h| < hcut) in the “transverse”
region as defined by the leading charged particle, PTmax, divided
by the area in h- space, 2hcut×2p/3, averaged over all events with
at least one particle with pT > 0.5 GeV/c, |h| < hcut.
PTmax Direction
D
“Toward”
“Transverse”
“Transverse”
“Away”
 “Transverse” Charged Particle Average PT: Event-by-event <pT> = PTsum/Nchg for charged
particles (pT > 0.5 GeV/c, |h| < hcut) in the “transverse” region as defined by the leading
charged particle, PTmax, averaged over all events with at least one particle in the
“transverse” region with pT > 0.5 GeV/c, |h| < hcut.
 Zero “Transverse” Charged Particles: If there are no charged particles in the “transverse”
region then Nchg and PTsum are zero and one includes these zeros in the average over all
events with at least one particle with pT > 0.5 GeV/c, |h| < hcut. However, if there are no
charged particles in the “transverse” region then the event is not used in constructing the
“transverse” average pT.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 23
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
PARP(82)
1.55
PARP(89)
CDF Data
Pythia 6.206 (default)
MSTP(82)=1
PARP(81) = 1.9 GeV/c
data uncorrected
theory corrected
0.75
0.50
1.9
1.9 the “underlying event”
Remember
2.1
2.1
1.9
activity
depends on both the
1,000 1,000 1,000
cut-off
pT0 and the PDF!
0.16
0.16
0.16
1.9
0.25
1.8 TeV |h|<1.0 PT>0.5 GeV
0.00
0
PARP(90)
PARP(67)
1.00
"Transverse" Charged Density
Parameter
"Transverse" Charged Particle Density: dN/dhd
5
10
15
20
25
30
35
40
45
50
PT(charged jet#1) (GeV/c)
4.0
4.0
1.0
1.0
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)
University of Glasgow Colloquium
October 16, 2013
Default parameters give
very poor description of
the “underlying event”!
Rick Field – Florida/CDF/CMS
Page 24
Run 1 PYTHIA Tune A
PYTHIA 6.206 CTEQ5L
CDF Default Feburary 25, 2000!
"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)
University of Glasgow Colloquium
October 16, 2013
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 25
All use LO as
with L = 192 MeV!
PYTHIA 6.2 Tunes
UE Parameters
ISR Parameter
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
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 26
Transverse Charged Particle Density
RDF LHC Prediction!
"Transverse" Charged Particle Density: dN/dhd
"Transverse" Charged Particle Density: dN/dhd
1.6
RDF Preliminary
PY64 Tune P329
"Transverse" Charged Density
"Transverse" Charged Density
0.8
generator level
0.6
0.4
PY Tune A
PY64 Tune N324
0.2
PY64 Tune S320
Min-Bias
1.96 TeV
PY ATLAS
RDF Preliminary
generator level
1.2
0.8
PY64 Tune P329
PY Tune A
0.4
0.0
PY Tune DW
PY64 Tune S320
If the LHC data are not in
the range shown here then
we learn new (QCD) physics!
Rick Field October 13, 2009
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
PY Tune DWT
Min-Bias
14 TeV
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
0
2
4
6
8
10
12
14
16
18
20
0
5
10
PTmax (GeV/c)
D
25
D
“Toward”
“Toward”
“Transverse”
20
PTmax Direction
PTmax Direction
“Transverse”
15
PTmax (GeV/c)
Tevatron
LHC
“Transverse”
“Transverse”
“Away”
“Away”
 Shows the “associated” charged particle density in the “transverse” region as a function of
PTmax for charged particles (pT > 0.5 GeV/c, |h| < 1, not including PTmax) for “min-bias” events
at 1.96 TeV from PYTHIA Tune A, Tune S320, Tune N324, and Tune P329 at the particle level (i.e.
generator level).
 Extrapolations of PYTHIA Tune A, Tune DW, Tune DWT, Tune S320, Tune P329, and pyATLAS to the
LHC.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 27
“Transverse” Charged Particle Density
"Transverse" Charged Particle Density: dN/dhd
"Transverse" Charged Particle Density: dN/dhd
1.2
RDF Preliminary
14 TeV
Min-Bias
"Transverse" Charged Density
"Transverse" Charged Density
1.2
py Tune DW generator level
10 TeV
7 TeV
0.8
1.96 TeV
0.9 TeV
0.4
0.2 TeV
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
RDF Preliminary
LHC14
py Tune DW generator level
0.8
LHC10
LHC7
Tevatron
900 GeV
0.4
PTmax = 5.25 GeV/c
RHIC
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
0
25
2
D
“Toward”
RHIC
“Transverse”
“Transverse”
0.2 TeV → 1.96 TeV
(UE increase ~2.7 times)
Tevatron
“Away”
6
8
10
12
14
Center-of-Mass Energy (TeV)
PTmax (GeV/c)
PTmax Direction
4
PTmax Direction
D
“Toward”
“Transverse”
PTmax Direction
1.96 TeV → 14 TeV
(UE increase ~1.9 times)
LHC
“Transverse”
“Away”
D
“Toward”
“Transverse”
“Transverse”
“Away”
 Shows the “associated” charged particle density in the “transverse” region as a function of
PTmax for charged particles (pT > 0.5 GeV/c, |h| < 1, not including PTmax) for “min-bias” events
at 0.2 TeV, 0.9 TeV, 1.96 TeV, 7 TeV, 10 TeV, 14 TeV predicted by PYTHIA Tune DW at the particle
Linear scale!
level (i.e. generator level).
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 28
“Transverse” Charged Particle Density
"Transverse" Charged Particle Density: dN/dhd
"Transverse" Charged Particle Density: dN/dhd
1.2
RDF Preliminary
14 TeV
Min-Bias
"Transverse" Charged Density
"Transverse" Charged Density
1.2
py Tune DW generator level
10 TeV
7 TeV
0.8
1.96 TeV
0.9 TeV
0.4
0.2 TeV
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
RDF Preliminary
py Tune DW generator level
LHC14
LHC10
LHC7
0.8
Tevatron
0.4
900 GeV
RHIC
PTmax = 5.25 GeV/c
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
0.1
D
“Toward”
LHC7
“Transverse”
100.0
PTmax Direction
7 TeV → 14 TeV
(UE increase ~20%)
D
“Toward”
LHC14
“Transverse”
“Away”
10.0
Center-of-Mass Energy (TeV)
PTmax (GeV/c)
PTmax Direction
1.0
Linear on a log plot!
“Transverse”
“Transverse”
“Away”
 Shows the “associated” charged particle density in the “transverse” region as a function of
PTmax for charged particles (pT > 0.5 GeV/c, |h| < 1, not including PTmax) for “min-bias” events
at 0.2 TeV, 0.9 TeV, 1.96 TeV, 7 TeV, 10 TeV, 14 TeV predicted by PYTHIA Tune DW at the particle
Log scale!
level (i.e. generator level).
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 29
“Transverse” Charge Density
"Transverse" Charged Particle Density: dN/dhd
Rick Field
MB&UE@CMS Workshop
CERN, November 6, 2009
"Transverse" Charged Density
1.2
RDF Preliminary
py Tune DW generator level
7 TeV
0.8
factor of 2!
900 GeV
0.4
Prediction!
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
4
10
0.0
0
2
6
8
12
14
16
18
20
PTmax (GeV/c)
PTmax Direction
D
LHC
900 GeV
“Toward”
“Transverse”
PTmax Direction
900 GeV → 7 TeV
(UE increase ~ factor of 2)
“Transverse”
“Away”
~0.4 → ~0.8
D
“Toward”
LHC
7 TeV
“Transverse”
“Transverse”
“Away”
 Shows the charged particle density in the “transverse” region for charged particles (pT > 0.5
GeV/c, |h| < 2) at 900 GeV and 7 TeV as defined by PTmax from PYTHIA Tune DW and at the
particle level (i.e. generator level).
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 30
PYTHIA Tune DW
"Transverse" Charged Particle Density: dN/dhd
"Transverse" Charged Particle Density: dN/dhd
Charged Particle Density
CMS Preliminary
"Transverse" Charged Density
1.2
7 TeV
data uncorrected
pyDW + SIM
0.8
CMS
900 GeV
0.4
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
1.2
RDF Preliminary
7 TeV
ATLAS corrected data
Tune DW generator level
0.8
ATLAS
900 GeV
0.4
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
30
35
40
45
50
0
2
4
6
8
10
 CMS preliminary data at 900 GeV and 7 TeV 
on the “transverse” charged particle density,
dN/dhd, as defined by the leading charged
particle jet (chgjet#1) for charged particles
with pT > 0.5 GeV/c and |h| < 2. The data are
uncorrected and compared with PYTHIA
Tune DW after detector simulation.
16
18
20
ATLAS preliminary data at 900 GeV and 7
TeV on the “transverse” charged particle
density, dN/dhd, as defined by the leading
charged particle (PTmax) for charged particles
with pT > 0.5 GeV/c and |h| < 2.5. The data are
corrected and compared with PYTHIA Tune
DW at the generator level.
PT(chgjet#1) Direction
PTmax Direction
D
D
“Toward”
“Toward”
“Transverse”
“Transverse”
“Away”
University of Glasgow Colloquium
October 16, 2013
14
PTmax (GeV/c)
PT(chgjet#1) GeV/c
“Transverse”
12
“Transverse”
“Away”
Rick Field – Florida/CDF/CMS
Page 31
PYTHIA Tune DW
"Transverse" Charged Particle Density: dN/dhd
"Transverse" Charged Particle Density: dN/dhd
3.0
1.2
CMS Preliminary
7 TeV
data uncorrected
pyDW + SIM
Ratio: 7 TeV/900 GeV
Charged Particle Density
CMS Preliminary
0.8
Ratio
CMS
900 GeV
0.4
data uncorrected
pyDW + SIM
2.0
CMS
1.0
7 TeV / 900 GeV
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
30
35
40
45
50
0
2
4
6
8
10
12
14
16
18
PT(chgjet#1) (GeV/c)
PT(chgjet#1) GeV/c
 CMS preliminary data at 900 GeV and 7 TeV  Ratio of CMS preliminary data at 900 GeV
and 7 TeV on the “transverse” charged
on the “transverse” charged particle density,
particle density, dN/dhd, as defined by the
dN/dhd, as defined by the leading charged
leading charged particle jet (chgjet#1) for
particle jet (chgjet#1) for charged particles
charged particles with pT > 0.5 GeV/c and
with pT > 0.5 GeV/c and |h| < 2. The data are
|h| < 2. The data are uncorrected and
uncorrected and compared with PYTHIA
compared with PYTHIA Tune DW after
Tune DW after detector simulation.
PT(chgjet#1) Direction
PT(chgjet#1) Direction
detector simulation.
D
D
“Toward”
“Transverse”
“Toward”
“Transverse”
“Transverse”
“Away”
University of Glasgow Colloquium
October 16, 2013
“Transverse”
“Away”
Rick Field – Florida/CDF/CMS
Page 32
PYTHIA Tune Z1
 All my previous tunes (A, DW, DWT, D6,
D6T, CW, X1, and X2) were PYTHIA 6.4
tunes using the old Q2-ordered parton
showers and the old MPI model (really 6.2
tunes)!
 I believe that it is time to move to PYTHIA
6.4 (pT-ordered parton showers and new
MPI model)!
 Tune Z1: I started with the parameters of
ATLAS Tune AMBT1, but I changed LO* to
CTEQ5L and I varied PARP(82) and PARP(90)
to get a very good fit of the CMS UE data at 900
GeV and 7 TeV.
 The ATLAS Tune AMBT1 was designed to fit
the inelastic data for Nchg ≥ 6 and to fit the
PTmax UE data with PTmax > 10 GeV/c. Tune
AMBT1 is primarily a min-bias tune, while
Tune Z1 is a UE tune!
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
PARP(90)
PARP(82)
Color
Connections
Diffraction
Outgoing Parton
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
Underlying Event
Final-State
Radiation
UE&MB@CMS
Page 33
CMS UE Data
"Transverse" Charged Particle Density: dN/dhd
"Transverse" Charged Particle Density: dN/dhd
1.2
1.2
CMS Preliminary
D6T
7 TeV
data uncorrected
Theory + SIM
Charged Particle Density
Charged Particle Density
CMS Preliminary
0.8
900 GeV
DW
0.4
CMS
7 TeV
data uncorrected
pyZ1 + SIM
0.8
900 GeV
0.4
CMS
Tune Z1
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
30
35
40
45
50
0
5
 CMS preliminary data at 900 GeV and 7
TeV on the “transverse” charged particle
density, dN/dhd, as defined by the leading
charged particle jet (chgjet#1) for charged
particles with pT > 0.5 GeV/c and |h| < 2.0.
The data are uncorrected and compared
with PYTHIA Tune DW and D6T after
detector simulation (SIM).
University of Glasgow Colloquium
October 16, 2013
15
20
25
30
35
40
45
50
PT(chgjet#1) GeV/c
PT(chgjet#1) GeV/c
Color reconnection suppression.
Color reconnection strength.
10
 CMS preliminary data at 900 GeV and 7
TeV on the “transverse” charged particle
density, dN/dhd, as defined by the leading
charged particle jet (chgjet#1) for charged
particles with pT > 0.5 GeV/c and |h| < 2.0.
The data are uncorrected and compared
with PYTHIA Tune Z1 after detector
simulation (SIM).
Tune Z1 (CTEQ5L)
PARP(82) = 1.932
PARP(90) = 0.275
PARP(77) = 1.016
PARP(78) = 0.538
Rick Field – Florida/CDF/CMS
Tune Z1 is a PYTHIA 6.4 using
pT-ordered parton showers and
the new MPI model!
Page 34
PYTHIA 6.4 Tune Z2
"Transverse" Charged PTsum Density: dPT/dhd
"Transverse" Charged Particle Density: dN/dhd
2.0
CMS Preliminary
CMS Preliminary
data corrected
Tune Z1 generator level
7 TeV
PTsum Density (GeV/c)
Charged Particle Density
1.6
1.2
0.8
900 GeV
CMS
0.4
Tune Z1
data corrected
Tune Z1 generator level
1.6
7 TeV
1.2
CMS
0.8
900 GeV
Tune Z1
0.4
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0.0
0
10
20
30
40
50
60
70
80
90
100
0
10
PT(chgjet#1) GeV/c
University of Glasgow Colloquium
October 16, 2013
30
40
50
60
70
80
90
100
PT(chgjet#1) GeV/c
 CMS preliminary data at 900 GeV and 7
TeV on the “transverse” charged particle
density, dN/dhd, as defined by the leading
charged particle jet (chgjet#1) for charged
particles with pT > 0.5 GeV/c and |h| < 2.0.
The data are corrected and compared with
PYTHIA Tune Z1 at the generator level.
CMS corrected
data!
20
 CMS preliminary data at 900 GeV and 7
TeV on the “transverse” charged PTsum
density, dPT/dhd, as defined by the leading
charged particle jet (chgjet#1) for charged
particles with pT > 0.5 GeV/c and |h| < 2.0.
The data are corrected and compared with
PYTHIA Tune Z1 at the generator level.
Very nice agreement!
Rick Field – Florida/CDF/CMS
CMS corrected
data!
Page 35
Tevatron Energy Scan
Proton
CDF
1 mile
AntiProton
Proton
900GeV
GeV
300
1.96
TeV
AntiProton
 Just before the shutdown of the Tevatron CDF
has collected more than 10M “min-bias” events
at several center-of-mass energies!
300 GeV 12.1M MB Events
900 GeV 54.3M MB Events
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 36
New UE Observables
 “transMAX” and “transMIN” Charged Particle Density: Number
of charged particles (pT > 0.5 GeV/c, |h| < 0.8) in the the maximum
(minimum) of the two “transverse” regions as defined by the
leading charged particle, PTmax, divided by the area in h- space,
2hcut×2p/6, averaged over all events with at least one particle with
pT > 0.5 GeV/c, |h| < hcut.
 “transMAX” and “transMIN” Charged PTsum Density: Scalar pT
sum of charged particles (pT > 0.5 GeV/c, |h| < 0.8) in the the
maximum (minimum) of the two “transverse” regions as defined
by the leading charged particle, PTmax, divided by the area in h-
space, 2hcut×2p/6, averaged over all events with at least one particle
with pT > 0.5 GeV/c, |h| < hcut.
PTmax Direction
D
“Toward”
“TransMAX”
“TransMIN”
“Away”
Note: The overall “transverse” density is equal to the average of the “transMAX” and
“TransMIN” densities. The “TransDIF” Density is the “transMAX” Density minus the
“transMIN” Density
“Transverse” Density = “transAVE” Density = (“transMAX” Density + “transMIN” Density)/2
“TransDIF” Density = “transMAX” Density - “transMIN” Density
hcut = 0.8
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 37
“transMIN” & “transDIF”
 The “toward” region contains the leading “jet”, while the “away”
region, on the average, contains the “away-side” “jet”. The
“transverse” region is perpendicular to the plane of the hard 2-to-2
scattering and is very sensitive to the “underlying event”. For
events with large initial or final-state radiation the “transMAX”
region defined contains the third jet while both the “transMAX”
and “transMIN” regions receive contributions from the MPI and
beam-beam remnants. Thus, the “transMIN” region is very
sensitive to the multiple parton interactions (MPI) and beam-beam
remnants (BBR), while the “transMAX” minus the “transMIN”
(i.e. “transDIF”) is very sensitive to initial-state radiation (ISR) Jet #3
and final-state radiation (FSR).
“TransMIN” density more sensitive to MPI & BBR.
PTmax Direction
“Toward-Side” Jet
D
“Toward”
“TransMAX”
“TransMIN”
“Away”
“Away-Side” Jet
“TransDIF” density more sensitive to ISR & FSR.
0 ≤ “TransDIF” ≤ 2×”TransAVE”
“TransDIF” = “TransAVE” if “TransMIX” = 3×”TransMIN”
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 38
PTmax UE Data
 CDF PTmax UE Analysis: “transMAX”, “transMIN”, “transAVE”,
and “transDIF” charged particle and PTsum densities (pT > 0.5
GeV/c, |h| < 0.8) in proton-antiproton collisions at 300 GeV, 900
GeV, and 1.96 TeV (R. Field analysis).
 CMS PTmax UE Analysis: “transMAX”, “transMIN”,
“transAVE”, and “transDIF” charged particle and PTsum densities
(pT > 0.5 GeV/c, |h| < 0.8) in proton-proton collisions at 900 GeV
and 7 TeV (M. Zakaria analysis). The “transMAX”, “transMIN”,
and “transDIF” are not yet approved so I can only show
“transAVE” which is approved.
PTmax Direction
D
“Toward”
“TransMAX”
“TransMIN”
“Away”
 CMS UE Tunes: PYTHIA 6.4 Tune Z1 (CTEQ5L) and PYTHIA 6.4
Tune Z2* (CTEQ6L). Both were tuned to the CMS leading chgjet
“transAVE” UE data at 900 GeV and 7 TeV.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 39
“transMAX/MIN” NchgDen
"Transverse" Charged Particle Density: dN/dhd
"Transverse"
1.2
CDF Preliminary
Preliminary
CDF
CorrectedData
Data
Corrected
Generator Level Theory
"Transverse"
"Transverse" Charged
Charged Density
Density
"Transverse" Charged Density
1.5
1.5
"Transverse" Charged Particle Density: dN/dhd
1.96 TeV
TeV
1.96
"TransMAX"
"TransMAX"
1.0
1.0
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
0.5
0.5
"TransMIN"
"TransMIN"
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
0.0
0.0
CDF
CDFPreliminary
Preliminary
Corrected
CorrectedData
Data
Generator Level Theory
900 GeV
"TransMAX"
0.8
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
0.4
"TransMIN"
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
0.0
00
44
88
12
12
16
16
20
20
0
4
8
PTmax (GeV/c)
(GeV/c)
PTmax
16
20
PTmax (GeV/c)
"Transverse" Charged Particle Density: dN/dhd
0.72
"Transverse" Charged
Charged Density
Density
"Transverse"
 Corrected CDF data at 1.96 TeV, 900 GeV,
and 300 GeV on the charged particle
density in the “transMAX” and
“transMIN” regions as defined by the
leading charged particle (PTmax) for
charged particles with pT > 0.5 GeV/c and
|h| < 0.8. The data are corrected to the
particle level with errors that include both
the statistical error and the systematic
uncertainty.
The data are compared with PYTHIA 6.4
Tune Z1 and Tune Z2*.
University of Glasgow Colloquium
October 16, 2013
12
CDF Preliminary
CDF Preliminary
300 GeV
Corrected Data
corrected data
Generator Level Theory
"TransMAX"
"TransMAX"
0.48
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
0.24
"TransMIN"
Charged Particles
Particles (|h|<0.8,
(|h|<0.8, PT>0.5
PT>0.5 GeV/c)
GeV/c)
Charged
0.00
0
Rick Field – Florida/CDF/CMS
2
4
6
8
10
12
PTmax (GeV/c)
Page 40
14
“transDIF/AVE” NchgDen
"Transverse"
"Transverse" Charged
Charged Particle
Particle Density:
Density: dN/dhd
dN/dhd
"Transverse" Charged Particle Density: dN/dhd
0.9
0.9
0.9
Corrected
CorrectedData
Data
Generator Level Theory
CDF Preliminary
"TransDIF"
Charged Particle Density
Charged Particle Density
CDF
CDF Preliminary
Preliminary
0.6
"TransAVE"
0.3
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
1.96 TeV
Corrected Data
Generator Level Theory
"TransDIF"
"TransDIF"
0.6
0.6
"TransAVE"
"TransAVE"
0.3
0.3
900
900 GeV
GeV
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
Charged
Charged Particles
Particles (|h|<0.8,
(|h|<0.8, PT>0.5
PT>0.5 GeV/c)
GeV/c)
0.0
0.0
0.0
0
4
8
12
16
00
20
44
88
16
16
20
20
PTmax
PTmax (GeV/c)
(GeV/c)
PTmax (GeV/c)
"Transverse" Charged Particle Density: dN/dhd
0.6
Charged Particle
Particle Density
Density
Charged
 Corrected CDF data at 1.96 TeV, 900 GeV,
and 300 GeV on the charged particle
density in the “transAVE” and “transDIF”
regions as defined by the leading charged
particle (PTmax) for charged particles
with pT > 0.5 GeV/c and |h| < 0.8. The data
are corrected to the particle level with
errors that include both the statistical
error and the systematic uncertainty.
The data are compared with PYTHIA 6.4
Tune Z1 and Tune Z2*.
University of Glasgow Colloquium
October 16, 2013
12
12
CDF Preliminary
Preliminary
CDF
CorrectedData
Data
Corrected
Generator Level Theory
"TransDIF"
0.4
"TransAVE"
0.2
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
300 GeV
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
0.0
0
2
Rick Field – Florida/CDF/CMS
4
6
8
10
12
PTmax (GeV/c)
Page 41
14
“transMAX/MIN” NchgDen
"TransMIN" Charged Particle Density: dN/dhd
"TransMIN"
"TransMAX" Charged
Charged Particle
Particle Density:
Density: dN/dhd
dN/dhd
"TransMAX"
0.39
0.39
CDF
CDFPreliminary
Preliminary
1.96 TeV
Corrected Data
Corrected Data
Generator Level Teory
1.96 TeV
Charged
Charged Particle
Particle Density
Density
Charged Particle
Density
"TransMAX"
Charged
Density
1.2
1.2
0.8
0.8
900 900
GeVGeV
300 GeV
0.4
0.4
300 GeV
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
ChargedParticles
Particles(|h|<0.8,
(|h|<0.8,PT>0.5
PT>0.5GeV/c)
GeV/c)
Charged
0.0
0.0
00
44
88
12
12
16
16
CDF Preliminary
1.96 TeV
0.26
0.26
900 GeV
900 GeV
0.13
0.13
300
GeV
Tune
Z2* (solid lines)
300 GeV
0.00
0.00
00
20
20
Tune Z1 (dashed lines)
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
44
88
12
12
16
16
20
20
PTmax (GeV/c)
(GeV/c)
PTmax
PTmax (GeV/c)
(GeV/c)
PTmax
"TransDIF"
"TransDIF" Charged
Charged Particle
Particle Density:
Density: dN/dhd
dN/dhd
0.9
0.8
CDF
CDFPreliminary
Preliminary
Charged Particle
Particle Density
Density
Charged
 Corrected CDF data at 1.96 TeV, 900 GeV,
and 300 GeV on the charged particle
density in the “transMAX”, “transMIN”,
and “transDIF” regions as defined by the
leading charged particle (PTmax) for
charged particles with pT > 0.5 GeV/c and
|h| < 0.8. The data are corrected to the
particle level with errors that include both
the statistical error and the systematic
uncertainty.
The data are compared with PYTHIA 6.4
Tune Z1 and Tune Z2*.
University of Glasgow Colloquium
October 16, 2013
1.96 TeV
Corrected Data
Generator Level Theory
0.6
0.6
1.961.96
TeVTeV
Corrected
CorrectedData
Data
Generator Level Theory
900
GeV
900
GeV
0.4
300 GeV
300 GeV
0.3
0.2
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
Charged
ChargedParticles
Particles(|h|<0.8,
(|h|<0.8,PT>0.5
PT>0.5GeV/c)
GeV/c)
0.0
0.0
00
Rick Field – Florida/CDF/CMS
44
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12
12
16
16
PTmax
PTmax (GeV/c)
(GeV/c)
Page 42
20
20
“transMAX/MIN” PTsumDen
"Transverse" Charged PTsum Density: dPT/dhd
"Transverse" Charged PTsum Density: dPT/dhd
1.2
1.5
Corrected
CorrectedData
Data
Generator Level Theory
1.96 TeV
1.0
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
0.5
CDF
Preliminary
CDF
Preliminary
"TransMAX"
PTsum
PTsum Density
Density (GeV/c)
(GeV/c)
PTsum Density (GeV/c)
CDF
CDFPreliminary
Preliminary
"TransMIN"
Corrected
Data
Corrected
Data
Generator Level Theory
900 GeV
"TransMAX"
0.8
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
0.4
"TransMIN"
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
0.0
0.0
0
4
8
12
16
0
20
4
8
16
20
"Transverse" Charged PTsum Density: dPT/dhd
0.72
CDFPreliminary
Preliminary
CDF
PTsum Density
Density (GeV/c)
(GeV/c)
PTsum
 Corrected CDF data at 1.96 TeV, 900 GeV,
and 300 GeV on the charged PTsum
density in the “transMAX” and
“transMIN” regions as defined by the
leading charged particle (PTmax) for
charged particles with pT > 0.5 GeV/c and
|h| < 0.8. The data are corrected to the
particle level with errors that include both
the statistical error and the systematic
uncertainty.
The data are compared with PYTHIA 6.4
Tune Z1 and Tune Z2*.
University of Glasgow Colloquium
October 16, 2013
12
PTmax (GeV/c)
PTmax (GeV/c)
300 GeV
CorrectedData
Data
Corrected
Generator Level Theory
"TransMAX"
0.48
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
0.24
"TransMIN"
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
0.00
0
2
Rick Field – Florida/CDF/CMS
4
6
8
10
12
PTmax (GeV/c)
Page 43
14
“transDIF/AVE” PTsumDen
dPT/dhd
"Transverse" Charged PTsum Density: dPT/dhd
"Transverse" Charged
Charged PTsum
PTsum Density:
Density: dPT/dhd
dPT/dhd
"Transverse"
0.9
0.9
1.2
1.2
CDF
CDFPreliminary
Preliminary
Corrected
Corrected Data
Data
Generator Level Theory
PTsum Density (GeV/c)
PTsum Density (GeV/c)
CDF Preliminary
"TransDIF"
"TransDIF"
0.8
0.8
"TransAVE"
"TransAVE"
0.4
0.4
Tune Z2* (solid lines)
1.96Z1TeV
Tune
(dashed lines)
1.96 TeV
Corrected
CorrectedData
Data
Generator Level Theory
"TransDIF"
"TransDIF"
0.6
0.6
"TransAVE"
"TransAVE"
0.3
0.3
Tune Z2* (solid lines)
900
Tune
Z1 GeV
(dashed lines)
900 GeV
Charged
ChargedParticles
Particles(|h|<0.8,
(|h|<0.8,PT>0.5
PT>0.5GeV/c)
GeV/c)
Charged Particles
Particles (|h|<0.8,
(|h|<0.8, PT>0.5
PT>0.5 GeV/c)
GeV/c)
Charged
0.0
0.0
0.0
0.0
00
44
88
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12
16
16
00
20
20
44
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16
16
20
20
PTmax (GeV/c)
(GeV/c)
PTmax
PTmax (GeV/c)
(GeV/c)
PTmax
"Transverse" Charged PTsum Density: dPT/dhd
0.6
CDF
CDFPreliminary
Preliminary
PTsum
PTsum Density
Density (GeV/c)
(GeV/c)
 Corrected CDF data at 1.96 TeV, 900 GeV,
and 300 GeV on the charged PTsum
density in the “transAVE” and “transDIF”
regions as defined by the leading charged
particle (PTmax) for charged particles
with pT > 0.5 GeV/c and |h| < 0.8. The data
are corrected to the particle level with
errors that include both the statistical
error and the systematic uncertainty.
The data are compared with PYTHIA 6.4
Tune Z1 and Tune Z2*.
University of Glasgow Colloquium
October 16, 2013
12
12
Corrected
CorrectedData
Data
Generator Level Theory
"TransDIF"
0.4
"TransAVE"
0.2
Tune Z2* (solid lines)
GeV lines)
Tune 300
Z1 (dashed
300 GeV
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
0.0
0
2
Rick Field – Florida/CDF/CMS
4
6
8
10
12
PTmax (GeV/c)
Page 44
14
“transMAX” NchgDen vs Ecm
"TransMAX" Charged Particle Density: dN/dhd
"TransMAX" Charged Particle Density: dN/dhd
0.96
CDF Preliminary
CDF Preliminary
1.96 TeV
Corrected Data
Charged Particle Density
"TransMAX" Charged Density
1.2
0.8
900 GeV
0.4
300 GeV
Corrected Data
0.64
0.32
5.0 < PTmax < 6.0 GeV/c
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
0.0
0.00
0
4
8
12
16
20
0.1
PTmax (GeV/c)
 Corrected CDF data at 1.96 TeV, 900 GeV,
and 300 GeV on the charged particle
density in the “transMAX” region as
defined by the leading charged particle
(PTmax) for charged particles with pT >
0.5 GeV/c and |h| < 0.8. The data are
corrected to the particle level with errors
that include both the statistical error and
the systematic uncertainty.
University of Glasgow Colloquium
October 16, 2013
1.0
10.0
Center-of-Mass Energy (GeV)
 Corrected CDF data on the charged particle
density in the “transMAX” region as
defined by the leading charged particle
(PTmax) for charged particles with pT > 0.5
GeV/c and |h| < 0.8 with 5 < PTmax < 6
GeV/c. The data are plotted versus the
center-of-mass energy (log scale).
Rick Field – Florida/CDF/CMS
Page 45
“TransMAX/MIN” vs Ecm
"Transverse"
Charged
PTsum
Density
Ratio
"Transverse"
Charged
PTsum
Density:
dPT/dhd
"Transverse"
Charged
Particle
Density
Ratio
"Transverse"
Charged
Particle
Density:
"Transverse"
Charged
Particle
DensitydN/dhd
Ratio
CDF
Preliminary
CDF
CDFPreliminary
Preliminary
corrected
data
corrected
data
corrected
data
generator
level
theory
generator
level
theory
generator
level
theory
1.0
3.8
4.8
7.3
1.8
6.4
CMS solid dots
CMS solid dots
CDF solid squares
CDF solid squares
5.0 < PTmax < 6.0 GeV/c
5.0<<PTmax
PTmax<<6.0
6.0GeV/c
GeV/c
5.0
Tune Z2* (solid lines)
Tune
(solidlines)
lines)
Tune
Z1Z2*
(dashed
Tune Z1 (dashed lines)
0.5
2.4
2.9
"TransMIN"
"TransMAX"
"TransMIN"
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
"TransMAX"
"TransMIN"
Divided by 300 GeV Value
Divided by 300 GeV Value
"TransMAX"
0.0
1.0
1.0
0.1
0.1
ChargedParticles
Particles(|h|<0.8,
(|h|<0.8,PT>0.5
PT>0.5GeV/c)
GeV/c)
Charged
1.0
1.0
10.0
10.0
100.0
Charged
PTsum
Density
(GeV/c)
Particle
Density
Ratio
Particle
Density
Ratio
Charged
ParticleParticle
DensityDensity
Ratio
Particle
Density
Ratio
1.5
5.2
6.7
CDF Preliminary
Preliminary
CDF
CMS
solid
dots
CMS
solid
dots
CMS
solid
dots
CDF
solid
squares
CDF
solid
squares
CDF
solid
squares
corrected data
data
corrected
generator level
level theory
theory
generator
5.2
1.2
4.6
"TransMIN"
"TransMAX"
5.0 < PTmax < 6.0 GeV/c
< PTmax
< 6.0
5.0 5.0
< PTmax
< 6.0
GeV/c
Tune Z2*GeV/c
(solid lines)
"TransMIN"
Tune
Z2* (solid
lines)
Tune
Z1 (dashed
lines)
"TransMAX"
Tune Z1
lines)
Divided
by(dashed
300 GeV
Value
3.1
0.6
2.8
Tune Z2* (solid lines)
"TransMIN"
"TransMAX"
Tune Z1 (dashed lines)
Divided by 300 GeV Value
1.0
0.0
0.1
0.1
Charged
ChargedParticles
Particles(|h|<0.8,
(|h|<0.8,PT>0.5
PT>0.5GeV/c)
GeV/c)
1.0
1.0
1.0
10.0
100.0
10.0
10.0
Center-of-Mass
Energy
(GeV)
Center-of-Mass
Center-of-MassEnergy
Energy (GeV)
(GeV)
Center-of-Mass Energy (GeV)
 Corrected CDF data at 1.96 TeV, 900 GeV,
 Corrected CDF data at 1.96 TeV, 900 GeV,
and 300 GeV on the charged PTsum density
and 300 GeV on the charged particle density
in the “transMAX”, and the “transMIN”,
in the “transMAX”, and the “transMIN”,
regions as defined by the leading charged
regions as defined by the leading charged
particle (PTmax) for charged particles with
particle (PTmax) for charged particles with
pT > 0.5 GeV/c and |h| < 0.8 with 5 < PTmax
pT > 0.5 GeV/c and |h| < 0.8 with 5 < PTmax
< 6 GeV/c. The data are plotted versus the
< 6 GeV/c. The data are plotted versus the
center-of-mass energy (log scale). The data
center-of-mass energy (log scale). The data
are compared with PYTHIA 6.4 Tune Z1
are compared with PYTHIA 6.4 Tune Z1
and Tune Z2*.
and Tune Z2*.
The data are “normalized” by dividing by the corresponding value at 300 GeV.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 46
“TransDIF/AVE” vs Ecm
"Transverse"
Charged
PTsum
Density:
dPT/dhd
"Transverse"
Charged
PTsum
Density
Ratio
"Transverse"
"Transverse"Charged
ChargedParticle
ParticleDensity:
DensitydN/dhd
Ratio
CDFPreliminary
Preliminary
CDF
correcteddata
data
corrected
generatorlevel
leveltheory
theory
generator
0.8
2.6
3.0
1.1
4.0
CMSCMS
solidsolid
dotsdots
CMS
solid
dots
squares
CDFCDF
solidsolid
squares
CDF
solid
squares
"TransAVE"
"TransAVE"
5.0Tune
< PTmax
< 6.0lines)
GeV/c
Z2* (solid
Tune Z2* (solid lines)
Tune
Z1
(dashed
Tune
Z1Z2*
(dashed
lines)
Tune
(solidlines)
lines)
"TransDIF"
Tune Z1 (dashed lines)
"TransDIF"
"TransAVE"
0.5 Divided by 300 GeV Value
1.8
2.0
Divided by 300 GeV Value
0.2
1.0
0.1
0.1
5.0<<PTmax
PTmax
6.0GeV/c
GeV/c
5.0
<<6.0
"TransDIF"
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
Charged Particles
Particles (|h|<0.8,
(|h|<0.8, PT>0.5
PT>0.5 GeV/c)
GeV/c)
Charged
1.0
1.0
1.0
10.0
10.0
10.0
100.0
Particle
Density
Ratio
Charged
PTsum
Density
(GeV/c)
Particle Particle
Density Density
Ratio
Charged
1.1
3.4
4.0
CDF Preliminary
CDF
CDF Preliminary
Preliminary
correcteddata
data
corrected
corrected data
generatorlevel
leveltheory
theory
generator
generator level theory
CMS solid dots
CMS solid dots
CDF
CDFsolid
solidsquares
squares
0.8
3.0
0.5
2.0
Tune Z2* (solid lines)
Tune
Z2* (solid
lines)
5.0
< PTmax
< 6.0
GeV/c
Tune Z1 (dashed lines)
Tune Z1 (dashed lines)
Tune Z2* (solid lines)
Tune Z1by
(dashed
lines)
Divided
300 GeV
Value
"TransDIF"
"TransDIF"
"TransAVE"
5.0 << PTmax
PTmax<<"TransDIF"
6.0GeV/c
GeV/c
5.0
6.0
Divided by 300 GeV Value
ChargedParticles
Particles(|h|<0.8,
(|h|<0.8,PT>0.5
PT>0.5GeV/c)
GeV/c)
Charged
Charged Particles
(|h|<0.8, PT>0.5
GeV/c)
0.2
1.0
0.1
0.1
"TransAVE"
"TransAVE"
1.0
1.0
10.0
100.0
10.0
Center-of-Mass Energy
Energy (GeV)
(GeV)
Center-of-Mass
Center-of-MassEnergy
Energy (GeV)
(GeV)
Center-of-Mass
Energy
(GeV)
Center-of-Mass
 Corrected CDF data at 1.96 TeV, 900 GeV,
 Corrected CDF data at 1.96 TeV, 900 GeV,
and 300 GeV on the charged PTsum density
and 300 GeV on the charged particle density
in the “transAVE”, and the “transDIF”,
in the “transAVE”, and the “transDIF”,
regions as defined by the leading charged
regions as defined by the leading charged
particle (PTmax) for charged particles with
particle (PTmax) for charged particles with
pT > 0.5 GeV/c and |h| < 0.8 with 5 < PTmax
pT > 0.5 GeV/c and |h| < 0.8 with 5 < PTmax
< 6 GeV/c. The data are plotted versus the
< 6 GeV/c. The data are plotted versus the
center-of-mass energy (log scale). The data
center-of-mass energy (log scale). The data
are compared with PYTHIA 6.4 Tune Z1
are compared with PYTHIA 6.4 Tune Z1
and Tune Z2*.
and Tune Z2*.
The data are “normalized” by dividing by the corresponding value at 300 GeV.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 47
“TransMIN/DIF” vs Ecm
"Transverse" Charged PTsum Density Ratio
"Transverse"
"Transverse" Charged
Charged Particle
Particle Density
Density Ratio
Ratio
7.3
5.8
6.7
5.2
corrected
corrected data
data
generator
generator level
level theory
theory
4.8
3.8
CMS solid dots
CDF solid squares
Tune Z2*
(solid
CMS
solidlines)
dots
Tune CDF
Z1 (dashed
lines)
solid squares
"TransMIN"
5.0
5.0 << PTmax
PTmax << 6.0
6.0 GeV/c
GeV/c
"TransMIN"
Tune Z2* (solid lines)
Tune Z1by
(dashed
lines)
Divided
300 GeV
Value
"TransDIF"
2.9
2.4
Divided by 300 GeV Value
1.0
1.0
0.1
0.1
"TransDIF"
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
Particle Density
Density Ratio
Ratio
Particle
Particle Density Ratio
CDF
CDF Preliminary
Preliminary
CDF Preliminary
corrected
corrected data
data
generator
generator level
level theory
theory
CMS
CMSsolid
soliddots
dots
CDF
CDFsolid
solidsquares
squares
5.0 < PTmax < 6.0 GeV/c
5.2
4.2
"TransMIN"
"TransMIN"
5.0
< Z2*
PTmax
< 6.0
GeV/c
Tune
(solid
lines)
Tune Z1 (dashed lines)
Tune Z2* (solid lines)
Tune Z1 (dashed lines)
3.1
2.6
Divided by 300 GeV Value
Divided by 300 GeV Value
"TransDIF"
"TransDIF"
Charged
ChargedParticles
Particles(|h|<0.8,
(|h|<0.8,PT>0.5
PT>0.5GeV/c)
GeV/c)
1.0
1.0
0.1
0.1
The
(MPI-BBR
component) increases
1.0
10.0
100.0
10.0
100.0
1.0
10.0
1.0 “transMIN”
10.0
Center-of-Mass
Center-of-Mass
(GeV)
Center-of-Mass Energy
Energy (GeV)
(GeV)
Center-of-Mass Energy
Energy
(GeV)faster with center-of-mass energy
much
than
the900
“transDIF”
component)!
 Ratio of CDF data at 1.96
TeV,
GeV, and (ISR-FSR
 Ratio of CDF data at 1.96 TeV, 900 GeV, and
300 GeV to the value at 300 GeV for the
300 GeV to the value at 300 GeV for the
charged particle density in the “transMIN”,
charged PTsum density in the “transMIN”,
and “transDIF” regions as defined by the
and “transDIF” regions as defined by the
leading charged particle (PTmax) for
leading charged particle (PTmax) for
charged particles with pT > 0.5 GeV/c and
charged particles with pT > 0.5 GeV/c and
|h| < 0.8 with 5 < PTmax < 6 GeV/c. The
|h| < 0.8 with 5 < PTmax < 6 GeV/c. The
data are plotted versus the center-of-mass
data are plotted versus the center-of-mass
energy (log scale). The data are compared
energy (log scale). The data are compared
with PYTHIA 6.4 Tune Z1 and Tune Z2*.
with PYTHIA 6.4 Tune Z1 and Tune Z2*.
1.0
The data are “normalized” by dividing by the corresponding value at 300 GeV.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 48
“Tevatron” to the LHC
"TransAVE" Charged Particle Density: dN/dhd
CMS
1.5
RDF Preliminary
13 TeV Predicted
Corrected Data
Tune Z2* Generator Level
Charged Particle Density
7 TeV
1.0
1.96 TeV
CDF
900 GeV
0.5
CDF
300 GeV
CDF
Tune Z2*
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
0.0
0
5
10
15
20
25
30
PTmax (GeV/c)
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 49
“Tevatron” to the LHC
"Transverse" Charged PTsum Density: dPT/dhd
1.8
RDF Preliminary
PTsum Density (GeV/c)
Corrected Data
Tune Z2* Generator Level
CMS
13 TeV Predicted
7 TeV
1.2
CDF
1.96 TeV
0.6
900 GeV
300 GeV
Tune Z2*
CDF
CDF
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
0.0
0
5
10
15
20
25
30
PTmax (GeV/c)
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 50
UE Publications
"Underlying Event" Publications
ATLAS Collaboration!
25
Number
Studying the Underlying EventOthers
in Drell-Yan and High
Transverse Momentum
Jet Production
at the Tevatron,
RDF
20
CDF Collaboration (Rick Field & Deepak Kar Ph.D. Thesis)
15
Deepak Kar
10
5
0
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
Year
 Publications with “underlying event” in the title.
The Underlying Event in Large Transverse Momentum
Charged Jet and Z−boson Production at CDF, R. Field,
published in the proceedings of DPF 2000.
Charged Jet Evolution and the Underlying Event in
Proton-Antiproton Collisions at 1.8 TeV,
CDF Collaboration, Phys. Rev. D65 (2002) 092002.
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 51
Summary & Conclusions
 The “transverse” density increases faster with center-of-mass energy
than the overall density (Nchg ≥ 1)! However, the “transverse” =
“transAVE” region is not a true measure of the energy dependence of
MPI since it receives large contributions from ISR and FSR.
What wecomponent)
are learning
should
 The “transMIN” (MPI-BBR
increases
much faster with
allow
forthan
a deeper
understanding
ofcomponent)!
MPI
center-of-mass
energy
the “transDIF”
(ISR-FSR
Previously we only
knew will
the energy
of “transAVE”.
which
resultdependence
in more precise
atMB
the future
We now predictions
have at lot of
& UE data at
energy
13 TeV!
300 GeV, LHC
900 GeV,
1.96ofTeV,
and 7 TeV!
We can study the energy dependence
more precisely than ever before!
 Both PYTHIA 6.4 Tune Z1 (CTEQ5L) and PYTHIA 6.4 Tune Z2*
(CTEQ6L) go a fairly good job (although not perfect) in describing the
energy deperdence of the UE!
University of Glasgow Colloquium
October 16, 2013
Rick Field – Florida/CDF/CMS
Page 52