Lake Louise Winter Institute
25 Years!
From Feynman-Field to the LHC
Rick Field
University of Florida
Outgoing Parton
Outline of Talk 1
PT(hard)
Chateau Lake Louise
February 2010
Initial-State Radiation
Proton
 The early days of Feynman-Field
AntiProton
Underlying Event
Underlying Event
Phenomenology.
 Studying “min-bias” collisions and
Outgoing Parton
Final-State
Radiation
the “underlying event” in Run 1 at
CDF.
CDF Run 2
 Tuning the QCD Monte-Carlo
UE&MB@CMS
model generators.
 Studying the “associated” charged
CMS at the LHC
particle densities in “min-bias”
collisions.
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 1
Toward and Understanding of
Hadron-Hadron Collisions
Feynman-Field Phenomenology1
Feynman
From 7 GeV/c
and
hat!
Field
Outgoing Parton
p0’s
to 600 GeV/c
Jets. The early days of trying to
understand and simulate hadronhadron collisions.
PT(hard)
Initial-State Radiation
Proton
AntiProton
Underlying Event
Outgoing Parton
Lake Louise Winter Institute
February 15, 2010
st
Rick Field – Florida/CDF/CMS
Underlying Event
Final-State
Radiation
Page 2
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”
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 3
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.
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Quark Fragmentation Functions
determined from e+e- annihilations
Page 4
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!
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 5
Feynman Talk at Coral Gables
(December 1976)
1st transparency
Last transparency
“Feynman-Field
Jet Model”
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 6
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
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 7
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
Lake Louise Winter Institute
February 15, 2010
 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 8
Feynman-Field Jet Model
R. P. Feynman
ISMD, Kaysersberg,
France, June 12, 1977
Feynman quote from FF2
“The predictions of the model are reasonable
enough physically that we expect it may
be close enough to reality to be useful in
designing future experiments and to serve
as a reasonable approximation to compare
to data. We do not think of the model
as a sound physical theory, ....”
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 9
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.”
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 10
CDF DiJet Event: M(jj) ≈ 1.4 TeV
ETjet1 = 666 GeV ETjet2 = 633 GeV
Esum = 1,299 GeV M(jj) = 1,364 GeV
M(jj)/Ecm ≈ 70%!!
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 11
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
my early days
yesterday
today
FF2 (1978)
Monte-Carlo
simulation of “jets”
“FF” or “FW”
Fragmentation
ISAJET
HERWIG
PYTHIA
(“FF” Fragmentation)
(“FW” Fragmentation)
(“String” Fragmentation)
SHERPA
Lake Louise Winter Institute
February 15, 2010
PYTHIA 6.4
Rick Field – Florida/CDF/CMS
HERWIG++
Page 12
Proton-Proton Collisions
Elastic Scattering
Single Diffraction
Double Diffraction
M2
M
M1
stot = sEL + sSD +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
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 13
Inelastic Non-Diffractive Cross-Section
Inelastic Non-Diffractive Cross-Section: sHC
Inelastic Non-Diffractive Cross-Section: sHC
70
70
RDF Preliminary
60
py Tune DW generator level
Cross-Section (mb)
Cross-Section (mb)
60
50
40
My guess!
30
20
10
RDF Preliminary
py Tune DW generator level
50
40
30
20
10
K-Factor = 1.2
K-Factor = 1.2
0
0
0
2
4
6
8
10
12
14
0.1
1.0
100.0
Center-of-Mass Energy (TeV)
Center-of-Mass Energy (TeV)
Linear scale!
10.0
Log scale!
stot = sEL + sSD +sDD +sND
 The inelastic non-diffractive cross section versus center-of-mass energy from PYTHIA (×1.2).
sHC varies slowly.
Only a 13% increase between 7 TeV (≈ 58 mb) and 14 teV (≈ 66 mb). Linear
on a log scale!
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 14
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!
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 15
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).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 16
MPI, Pile-Up, and Overlap
MPI: Multiple Parton Interactions
Outgoing Parton
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
 MPI: Additional 2-to-2 parton-parton
scatterings within a single hadron-hadron
collision.
Underlying Event
Outgoing Parton
Final-State
Radiation
Proton
Pile-Up
Pile-Up
Proton
Proton
Proton
Primary
Interaction Region Dz
 Pile-Up: More than one hadron-hadron collision in the beam
crossing.
Overlap
 Overlap: An experimental timing issue where a hadron-hadron
collision from the next beam crossing gets included in the hadronhadron collision from the current beam crossing because the next
crossing happened before the event could be read out.
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 17
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.
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 18
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!
2p
“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 = 4p/3.
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 19
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)
Lake Louise Winter Institute
February 15, 2010
Default parameters give
very poor description of
the “underlying event”!
Rick Field – Florida/CDF/CMS
Page 20
Tuning PYTHIA:
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
Multiple PartonDetermine
Interactionby comparing
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.
with 630 GeV data!
Color String
Hard-Scattering Cut-Off PT0
Determines the reference energy E0.
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.
Lake Louise Winter Institute
February 15, 2010
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 21
“Transverse” Cones
vs “Transverse” Regions
“Cone Analysis”
2p
2p
Transverse
Cone:
p(0.7)2=0.49p
Away Region
Transverse
Region

(Tano, Kovacs, Huston, Bhatti)
Cone 1

Leading
Jet
Leading
Jet
Toward Region
Transverse
Region:
2p/3=0.67p
Transverse
Region
Cone 2
Away Region
0
0
-1
h
+1
-1
h
+1
 Sum the PT of charged particles in two cones of radius
0.7 at the same h as the leading jet but with |DF| = 90o.
 Plot the cone with the maximum and minimum PTsum
versus the ET of the leading (calorimeter) jet.
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 22
Energy Dependence
of the “Underlying Event”
“Cone Analysis”
(Tano, Kovacs, Huston, Bhatti)
630 GeV
1,800 GeV
PYTHIA 6.115
PT0 = 1.4 GeV
PYTHIA 6.115
PT0 = 2.0 GeV
 Sum the PT of charged particles (pT > 0.4 GeV/c) in two cones of radius 0.7 at the same h as the leading
jet but with |DF| = 90o. Plot the cone with the maximum and minimum PTsum versus the ET of the
leading (calorimeter) jet.
 Note that PYTHIA 6.115 is tuned at 630 GeV with PT0 = 1.4 GeV and at 1,800 GeV with PT0 = 2.0 GeV.
This implies that e = PARP(90) should be around 0.30 instead of the 0.16 (default).
 For the MIN cone 0.25 GeV/c in radius R = 0.7 implies a PTsum density of dPTsum/dhd = 0.16 GeV/c
and 1.4 GeV/c in the MAX cone implies dPTsum/dhd = 0.91 GeV/c (average PTsum density of 0.54
GeV/c per unit h-).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 23
“Transverse” Charged Densities
Energy Dependence
Rick Field Fermilab MC Workshop
October 4, 2002!
"Transverse" Charged PTsum Density: dPTsum/dhd
0.60
"Min Transverse" PTsum Density: dPTsum/dhd
0.3
Charged PTsum Density (GeV)
Charged PTsum Density (GeV)
e = 0.25
HERWIG 6.4
0.40
e = 0.16
e=0
0.20
HERWIG 6.4
e = 0.25
0.2
Increasing e produces less energy
dependence for the
UE resulting
in
e = 0.16
e=0
less UE activity at the LHC!
CTEQ5L
Pythia 6.206 (Set A)
Pythia 6.206 (Set A)
630 GeV |h|<1.0 PT>0.4 GeV
0.1
CTEQ5L
630 GeV |h|<1.0 PT>0.4 GeV
0.0
0.00
0
5
10
15
20
25
30
35
40
45
50
0
5
10
Lowering PT0 at 630 GeV (i.e.
increasing e) increases UE activity
charged
PTsum density
resulting in
less energy dependence.
25
30
35
40
45
50
Hard-Scattering Cut-Off PT0
5
PYTHIA 6.206
e = 0.25 (Set A))
4
PT0 (GeV/c)
(|h|<1, PT>0.4 GeV) versus PT(charged jet#1) at 630
GeV predicted by HERWIG 6.4 (PT(hard) > 3
GeV/c, CTEQ5L) and a tuned version of PYTHIA
6.206 (PT(hard) > 0, CTEQ5L, Set A, e = 0, e = 0.16
(default) and e = 0.25 (preferred)).
 Also shown are the PTsum densities (0.16 GeV/c and
0.54 GeV/c) determined from the Tano, Kovacs,
Huston, and Bhatti “transverse” cone analysis at
630 GeV.
Lake Louise Winter Institute
February 15, 2010
20
PT(charged jet#1) (GeV/c)
PT(charged jet#1) (GeV/c)
 Shows the “transverse”
15
3
2
e = 0.16 (default)
1
100
Rick Field – Florida/CDF/CMS
1,000
10,000
100,000
CM Energy W (GeV)
Reference point
E0 = 1.8 TeV
Page 24
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)
Lake Louise Winter Institute
February 15, 2010
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
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.
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 26
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)!
Lake Louise Winter Institute
February 15, 2010
20
Rick Field – Florida/CDF/CMS
Page 27
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).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 28
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!
Lake Louise Winter Institute
February 15, 2010
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
Lake Louise Winter Institute
February 15, 2010
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
ATLAS energy dependence!
PARP(84)
0.4
0.4
Tune
B 0.5
Tune
AW
Tune BW
These are 1.0
“old” PYTHIA
6.2
PARP(85)
1.0
0.33 tunes!
are new 6.420
tunes
PARP(86)There 1.0
1.0
0.66 by
PARP(89)
1.96 TeV
TeV
1.0 TeV
Peter Skands
(Tune1.96S320,
update
of S0)
PARP(90)
0.16
0.16 N324,0.16
Peter Skands
(Tune
N0CR)
PARP(62)
1.25
1.25
1.0
Hendrik Hoeth (Tune P329, “Professor”)
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
Lake Louise Winter Institute
February 15, 2010
1.0
Tune D6
CMS
Rick Field – Florida/CDF/CMS
Page 31
Peter’s Pythia Tunes WEBsite
 http://home.fnal.gov/~skands/leshouches-plots/
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 32
“Transverse” Charged Density
PTmax Direction
D
"Transverse" Charged Particle Density: dN/dhd
0.8
“Transverse”
“Transverse”
“Away”
ChgJet#1 Direction
D
“Toward”
“Transverse”
“Transverse”
“Away”
"Transverse" Charged Density
“Toward”
RDF Preliminary
1.96 TeV
py Tune A generator level
0.6
0.6
0.4
Jet#1
ChgJet#1
0.2
PTmax
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
Jet#1 Direction
D
0
5
10
15
20
25
30
PT(jet#1) or PT(chgjet#1) or PTmax (GeV/c)
“Toward”
“Transverse”
“Transverse”
“Away”
 Shows the charged particle density in the “transverse” region for charged particles (pT > 0.5
GeV/c, |h| < 1) at 1.96 TeV as defined by PTmax, PT(chgjet#1), and PT(jet#1) from PYTHIA
Tune A at the particle level (i.e. generator level).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 33
Min-Bias “Associated”
Charged Particle Density
About a factor of 2.7 increase in
Associated Charged Particle Density: dN/dhd
the “transverse” region!
1.2
1.6
py Tune DW generator level
RDF Preliminary
Min-Bias
1.96 TeV
Charged Particle Density
RDF Preliminary
Charged Particle Density
Associated Charged Particle Density: dN/dhd
1.2
"Toward"
"Away"
0.8
"Transverse"
0.4
py Tune DW generator level
Min-Bias
0.2 TeV
"Away"
0.8
"Toward"
0.4
"Transverse"
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
0.0
0
2
4
6
8
10
12
16
18
20
0
2
4
6
8
10
PTmax (GeV/c)
PTmax (GeV/c)
PTmax Direction
PTmax Direction
D
“Toward”
Tevatron
14
“Transverse”
1.96 TeV ← 0.2 TeV
(~factor of 10 increase)
“Transverse”
12
14
D
“Toward”
RHIC
“Transverse”
“Transverse”
“Away”
“Away”
 Shows the “associated” charged particle density in the “toward”, “away” and “transverse” regions
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 and at 0.2 TeV from PYTHIA Tune DW at the particle level (i.e.
generator level).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 34
Min-Bias “Associated”
Charged Particle Density
About a factor of 2 increase in the
Associated Charged Particle Density: dN/dhd
“transverse” region!
1.6
py Tune DW generator level
Min-Bias
14 TeV
RDF Preliminary
Min-Bias
1.96 TeV
Charged Particle Density
RDF Preliminary
Charged Particle Density
Charged Particle Density: dN/dhd
2.5
1.2
"Toward"
"Away"
0.8
"Transverse"
0.4
py Tune DW generator level
2.0
"Toward"
"Away"
1.5
"Transverse"
1.0
0.5
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
0.0
0
2
4
6
8
10
12
14
16
18
20
0
5
10
Tevatron
“Transverse”
25
PTmax Direction
PTmax Direction
“Toward”
20
PTmax (GeV/c)
PTmax (GeV/c)
D
15
1.96 TeV → 14 TeV
(~factor of 7 increase)
“Transverse”
D
“Toward”
LHC
“Transverse”
“Transverse”
“Away”
“Away”
 Shows the “associated” charged particle density in the “toward”, “away” and “transverse” regions
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 and at 14 TeV from PYTHIA Tune DW at the particle level (i.e.
generator level).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 35
Min-Bias “Associated”
Charged Particle Density
35% more at RHIC means
"Transverse" Charged Particle Density: dN/dhd
26% less at the LHC!
1.6
RDF Preliminary
"Transverse" Charged Density
0.3
"Transverse" Charged Density
"Transverse" Charged Particle Density: dN/dhd
PY Tune DW
generator level
0.2
~1.35
PY Tune DWT
0.1
Min-Bias
0.2 TeV
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
RDF Preliminary
PY Tune DWT
generator level
1.2
~1.35
0.8
PY Tune DW
0.4
Min-Bias
14 TeV
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
0.0
0
2
4
6
8
10
12
14
16
18
20
0
2
4
6
8
PTmax Direction
D
“Toward”
“Transverse”
12
14
16
18
20
PTmax (GeV/c)
PTmax (GeV/c)
RHIC
10
PTmax Direction
0.2 TeV → 14 TeV
(~factor of 70 increase)
“Transverse”
“Away”
D
“Toward”
LHC
“Transverse”
“Transverse”
“Away”
 Shows the “associated” charged particle density in the “transverse” regions 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 and 14 TeV from PYTHIA Tune DW and Tune DWT at the particle level (i.e. generator
level). The STAR data from RHIC favors Tune DW!
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 36
Min-Bias “Associated”
Charged Particle Density
"Transverse" Charged Particle Density: dN/dhd
"Transverse" Charged Density
1.2
RDF Preliminary
14 TeV
Min-Bias
py Tune DW generator level
0.8
~1.9
0.4
1.96 TeV
~2.7
0.2 TeV
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
0
5
10
15
20
25
PTmax (GeV/c)
PTmax Direction
D
“Toward”
RHIC
“Transverse”
“Transverse”
0.2 TeV → 1.96 TeV
(UE increase ~2.7 times)
Tevatron
“Away”
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, 1.96 TeV and 14 TeV predicted by PYTHIA Tune DW at the particle level (i.e. generator
level).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 37
The “Underlying Event” at STAR
 At STAR they have measured the “underlying event at W = 200 GeV (|h| < 1, pT > 0.2 GeV)
and compared their uncorrected data with PYTHIA Tune A + STAR-SIM.
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 38
The “Underlying Event” at STAR
Charged PTsum Density
Charged PTsum
"Transverse"
PTsumDensity
Density (GeV/c)
(GeV/c)
"Transverse"
PTsum Density:
dPT/dhd
ChargedCharged
PTsum Density:
dPT/dhd
2.0
100.0
1.6
“Back-to-Back”
Charged Particles (|h|<1.0, PT>0.2 GeV/c)
Data uncorrected
PYTHIA Tune A + STAR-SIM
CDF
Run
2 Preliminary
CDF
Run
2 Preliminary
data corrected
particle level
datatocorrected
10.0
1.2
pyA
generator level
1.96
TeV
"Leading Jet"
"Toward"
PY Tune A
"Away"
“Toward”
"Transverse"
0.8
1.0
"Back-to-Back"
"Leading Jet"
MidPoint R=0.7 |h(jet#1)|<2
0.4
0.1
0.0
0
0
50
“Away”
MidPoint
R = Particles
0.7 |h(jet#1)
< 2 PT>0.5 GeV/c)
Charged
(|h|<1.0,
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
HW
50
0.55
100
150
200
250
100
150
200
250
300
300
350
350
400
400
450
Preliminary
~1.5
PT(jet#1) (GeV/c)
PT(jet#1) (GeV/c)
Jet #1 Direction
D
D
“Leading Jet”
“Toward”
“Transverse”
“Transverse”
“Away”
“Transverse”
Jet #1 Direction
0.37
“Toward”
“Transverse”
PT(jet#1) (GeV/c)
“Transverse”
“Away”
“Back-to-Back”
Jet #2 Direction
 Data on the charged particle scalar pT sum density, dPT/dhd, as a function of the leading jet pT for the
“toward”, “away”, and “transverse” regions compared with PYTHIA Tune A.
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 39
Min-Bias “Associated”
Charged Particle Density
“Associated” densities do
not include PTmax!
Highest pT
charged particle!
Charged Particle Density: dN/dhd
PTmax Direction
PTmax Direction
0.5
D
Correlations in 
Charged Particle Density
CDF Preliminary
Associated Density
PTmax not included
data uncorrected
0.4
D
Charge Density
0.3
0.2
0.1
Min-Bias
Correlations
in 
Charged Particles
(|h|<1.0, PT>0.5 GeV/c)
PTmax
0.0
0
30
60
90
120
150
180
210
240
270
300
330
360
D (degrees)
 Use the maximum pT charged particle in the event, PTmax, to define a direction and look
It is more probable
to find
a particle
at the the “associated”
density, dN
chg/dhd,
in “min-bias” collisions (pT > 0.5 GeV/c, |h| <
accompanying
PTmax
than
it
is
to
1).
find a particle in the central region!
 Shows the data
on the D dependence of the “associated” charged particle density,
dNchg/dhd, for charged particles (pT > 0.5 GeV/c, |h| < 1, not including PTmax) relative
to PTmax (rotated to 180o) for “min-bias” events. Also shown is the average charged
particle density, dNchg/dhd, for “min-bias” events.
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 40
Min-Bias “Associated”
Charged Particle Density
Rapid rise in the particle
density in the “transverse”
region as PTmax increases!
Associated Particle Density: dN/dhd
PTmaxDirection
Direction
PTmax
D
“Toward”
“Transverse”
“Transverse”
Correlations in 
“Away”
Associated Particle Density
Jet #1
D
PTmax > 2.0 GeV/c
1.0
PTmax > 2.0 GeV/c
PTmax > 1.0 GeV/c
0.8
Charged Particles
(|h|<1.0, PT>0.5 GeV/c)
CDF Preliminary
data uncorrected
PTmax > 0.5 GeV/c
Transverse
Region
0.6
Transverse
Region
0.4
0.2
Jet #2
PTmax
PTmax not included
Min-Bias
0.0
0
30
60
90
120
150
180
210
240
270
300
330
360
D (degrees)
Ave Min-Bias
0.25 per unit h-
PTmax > 0.5 GeV/c
 Shows the data on the D dependence of the “associated” charged particle density,
dNchg/dhd, for charged particles (pT > 0.5 GeV/c, |h| < 1, not including PTmax) relative
to PTmax (rotated to 180o) for “min-bias” events with PTmax > 0.5, 1.0, and 2.0 GeV/c.
 Shows “jet structure” in “min-bias” collisions (i.e. the “birth” of the leading two jets!).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 41
Min-Bias “Associated”
Charged Particle Density
PY Tune A
PTmax > 2.0 GeV/c
PTmax Direction
Direction
PTmax
D
“Toward”
“Transverse”
“Transverse”
Correlations in 
“Away”
PTmax > 2.0 GeV/c
Associated Particle Density
D
Associated Particle Density: dN/dhd
1.0
CDF Preliminary
PY Tune A
0.8
data uncorrected
theory + CDFSIM
PTmax > 0.5 GeV/c
PY Tune A
Transverse
Region
0.6
PY Tune A 1.96 TeV
Transverse
Region
0.4
0.2
PTmax
PTmax not included
(|h|<1.0, PT>0.5 GeV/c)
0.0
0
30
60
90
120
PTmax > 0.5 GeV/c
150
180
210
240
270
300
330
360
D (degrees)
 Shows the data on the D dependence of the “associated” charged particle density,
dNchg/dhd, for charged particles (pT > 0.5 GeV/c, |h| < 1, not including PTmax) relative
to PTmax (rotated to 180o) for “min-bias” events with PTmax > 0.5 GeV/c and PTmax >
2.0 GeV/c compared with PYTHIA Tune A (after CDFSIM).
 PYTHIA Tune A predicts a larger correlation than is seen in the “min-bias” data (i.e.
Tune A “min-bias” is a bit too “jetty”).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 44
Min-Bias “Associated”
Charged Particle Density
PTmax Direction
Associated Charged
Charged
Particle
Density:
dN/dhd
Associated
"Transverse"
ChargedParticle
ParticleDensity:
Density:dN/dhd
dN/dhd
D
Associated Charged Particle Density: dN/dhd
10.0
Charged Particle Density
py Tune A generator level
“Toward” Region
PTmax > 2.0 GeV/c
PTmax > 5.0 GeV/c
1.0
PTmax > 10.0 GeV/c
“Transverse”
“Transverse”
0.1
Min-Bias
1.96 TeV
PTmax > 0.5 GeV/c
PTmax > 1.0 GeV/c
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.0
Density
"Transverse"
Charged
Density
Charged Particle
1.6
2.5
1.2
RDF Preliminary
RDF Preliminary
RDF Preliminary
py Tune A generator level
py Tune A generator level
1.0
2.0
1.2
0.8
1.5
Min-Bias
Min-Bias
Min-Bias
14 TeV
1.96 TeV
“Toward”
14 TeV
"Toward"
"Away"
"Toward"
“Transverse”
~ factor of "Away"
2!
“Transverse”
0.8
0.6
1.0
0.4
0.4
0.5
0.2
1.96 TeV
"Transverse"
"Transverse"
“Away”
Charged
ChargedParticles
Particles(|h|<1.0,
(|h|<1.0,PT>0.5
PT>0.5 GeV/c)
GeV/c)
Charged
Particles
(|h|<1.0,
PT>0.5
GeV/c)
0.0
0.0
0
30
60
90
120
150
180
210
240
270
300
330
360
00
2
D (degrees)
54
6
8
10
10
12
15
14
16
20
18
PTmax (GeV/c)
(GeV/c)
PTmax
 Shows the D dependence of the “associated” charged particle density, dNchg/dhd, for charged
particles (pT > 0.5 GeV/c, |h| < 1, not including PTmax) relative to PTmax (rotated to 180o) for
“min-bias” events at 1.96 TeV with PTmax > 0.5, 1.0, 2.0, 5.0, and 10.0 GeV/c from PYTHIA
Tune A (generator level).
PTmax Direction
D
“Toward”
“Transverse”
“Transverse”
“Away”
 Shows the “associated” charged particle density in the “toward”, “away” and
“transverse” regions 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 (generator level).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 46
25
20
25
“Associated” Charged Particle Density
PY Tune DW
Associated Charged Particle Density: dN/dhd
Associated Charged Particle Density: dN/dhd
0.60
RDF Preliminary
Associated Charged Density
Associated Charged Density
0.60
generator level
0.40
0.20
Excluding PT1
900 GeV
pyDW PT1 > 2 GeV/c <Nasc> = 10.3
Charged Particles
(|h|<2.0, PT>0.5 GeV/c)
0.00
-180 -150 -120
-90
-60
pyDWPro PT1 > 2 GeV/c <Nasc> = 9.5
-30
0
30
60
90
120
150
180
RDF Preliminary
generator level
0.40
0.20
Excluding PT1
900 GeV
0.00
-180 -150 -120
-90
D (degrees)
PY Tune DWPro
pyDW PT1 > 2 GeV/c <Nasc> = 10.3
Charged Particles
(|h|<2.0, PT>0.5 GeV/c)
-60
pyS320 PT1 > 2 GeV/c <Nasc> = 9.2
-30
0
30
60
90
120
150
180
D (degrees)
PY Tune S320
 Shows the D dependence of the “associated” charged particle density, dNchg/dhd,
for charged particles (pT > 0.5 GeV/c, |h| < 2, not including PTmax) relative to
PTmax at 900 GeV with PTmax > 2.0 GeV/c from PYTHIA Tune DW, Tune DWPro,
and Tune S320 (generator level).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 47
Charged Particle Density dN/dhd
Charged
Particle
Density:
dN/dhd
Associated
Charged
Particle
Density:
dN/dhd
Associated Charged Particle Density: dN/dhd
2.5
0.60
RDFPreliminary
Preliminary
RDF
Associated
Charged
Density
Charged Particle
Density
Associated Charged
Charged Density
Density
Associated
0.60
pyDW
gnerator
level
pyDW
gnerator
level
0.40
0.20
900 GeV
900 GeV
Excluding PT1
Excluding
PT1
Charged Particles
Charged Particles
(|h|<2.0, PT>0.5 GeV/c)
(|h|<2.0, PT>0.5 GeV/c)
0.00
0.00
-180
-180 -150
-150 -120
-120
-90
-90
-60
-60
PTCJ1 > 2 GeV/c <Nasc> = 8.4
10.3
pyDW PT1 > 2 GeV/c <Nasc> = 10.3
-30
-30
0
0
30
30
60
60
90
90
120
120
150
150
180
180
RDF
Preliminary
RDF
Preliminary
2.0
0.40
1.5
PTCJ1 > 2 GeV/c <Nchg> = 10.7
pyDW gnerator level
pyDW gnerator level
900 GeV
Charged Particles
(|h|<2.0, PT>0.5 GeV/c)
1.0
0.20
Excluding PTCJ1
900 GeV
0.5
Charged Particles
(|h|<2.0, PT>0.5 GeV/c)
0.0
0.00
-180
-180 -150
-150 -120
-120 -90
-90
-60
-60
PTCJ1 > 2 GeV/c <Nasc> = 8.4
-30
-30
00
30
30
60
60
90
90
120
120
150
180
D
D (degrees)
(degrees)
D
D (degrees)
(degrees)
 Shows the D dependence of the “associated” charged particle density, dNchg/dhd,
for charged particles (pT > 0.5 GeV/c, |h| < 2, not including PTmax) relative to
PTmax (rotated to 180o) at 900 GeV with PTmax > 2.0 GeV/c from PYTHIA Tune
DW.
 Shows the D dependence of the “overall” and “associated” charged particle density,
dNchg/dhd, for charged particles (pT > 0.5 GeV/c, |h| < 2, including all particles)
relative to the leading charged particle jet (Anti-KT, d = 0.5) at 900 GeV with
PTmax > 2.0 GeV/c from PYTHIA Tune DW (generator level).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 48
Charged Particle Density dN/dhd
AntiKT d = 0.5
Associated Charged Particle Density: dN/dhd
Charged Particle Density: dN/dhd
0.60
2.4
Charged Particle Density
RDF Preliminary
PTCJ1 > 2 GeV/c <NCJ1> = 2.3
pyDW gnerator level
1.8
1.2
Associated Charged Density
PTCJ1 > 2 GeV/c <Nchg> = 10.7
PTCJ1 > 2 GeV/c <Nasc> = 8.4
900 GeV
Charged Particles
(|h|<2.0, PT>0.5 GeV/c)
0.6
0.0
-180 -150 -120
-90
-60
-30
0
30
60
90
120
150
180
RDF Preliminary
pyDW gnerator level
0.40
0.20
Excluding PTCJ1
900 GeV
Charged Particles
(|h|<2.0, PT>0.5 GeV/c)
0.00
-180 -150 -120
D (degrees)
-90
-60
PTCJ1 > 2 GeV/c <Nasc> = 8.4
PTCJ1 > 2 GeV/c <Nasc> = 7.4
-30
0
30
60
90
120
150
180
D (degrees)
AntiKT d = 0.7
 Shows the D dependence of the “overall” and “associated” charged particle density,
dNchg/dhd, for charged particles (pT > 0.5 GeV/c, |h| < 2, including all particles)
relative to the leading charged particle jet (Anti-KT, d = 0.5) at 900 GeV with
PTmax > 2.0 GeV/c from PYTHIA Tune DW (generator level).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 49
Min-Bias “Associated”
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 level
Linear scale!
(i.e. generator level).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 50
Min-Bias “Associated”
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 level
Log scale!
(i.e. generator level).
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 51
Lake Louise Winter Institute
Extrapolating from the Tevatron to the LHC
Rick Field
University of Florida
Outgoing Parton
Outline of Talk 2 (tomorrow)
 The latest “underlying event”
PT(hard)
Initial-State Radiation
Proton
AntiProton
Underlying Event
studies at CDF for “leading Jet”
and Z-boson events. Data
corrected to the particle level.
Outgoing Parton
Underlying Event
Final-State
Radiation
CDF Run 2
 Min-Bias and the “underlying event”.
 Studying <pT> versus Nchg in
UE&MB@CMS
“min-bias” collisions and in Drell-Yan.
 UE studies at 900 GeV from CMS and
Chateau Lake Louise
February 2010
CMS at the LHC
ATLAS coming soon!
 LHC predictions!
Lake Louise Winter Institute
February 15, 2010
Rick Field – Florida/CDF/CMS
Page 52