1st Workshop on Energy Scaling
in Hadron-Hadron Collisions
Fermilab 2009
Rick’s View of Hadron Collisions
Rick Field
University of Florida
Outline of Talk
Outgoing Parton
PT(hard)
The early days of Feynman-Field
Proton
Phenomenology.
Initial-State Radiation
AntiProton
Underlying Event
Studying “min-bias” collisions and
the “underlying event” in Run 1 at
CDF.
Outgoing Parton
Underlying Event
Final-State
Radiation
Tuning the QCD Monte-Carlo
model generators.
Studying the “associated” charged
particle densities in “min-bias”
collisions.
Fermilab Energy Scaling Workshop
April 27, 2009
CDF Run 2
Rick Field – Florida/CDF/CMS
CMS at the LHC
Page 1
Toward and Understanding of
Hadron-Hadron Collisions
Feynman-Field Phenomenology1
Feynman
From 7 GeV/c
and
st
hat!
Field
Outgoing Parton
π0’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
Fermilab Energy Scaling Workshop
April 27, 2009
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?
Most of the time the hadrons ooze
through each other and fall apart (i.e.
no hard scattering). The outgoing
particles continue in roughly the same
direction as initial proton and
antiproton.
Occasionally there will be a large
transverse momentum meson.
Question: Where did it come from?
Hadron
Hadron
???
Parton-Parton Scattering
Outgoing Parton
“Soft” Collision (no large transverse momentum)
Hadron
We assumed it came from quark-quark
elastic scattering, but we did not know
how to calculate it!
Hadron
Outgoing Parton
high PT meson
“Black-Box Model”
Fermilab Energy Scaling Workshop
April 27, 2009
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.
of others
who are similarly analyzing
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
fragment
or cascade down
into several hadrons.”
Occasionally there will
be a large
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”
Fermilab Energy Scaling Workshop
April 27, 2009
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
Quark-Quark Cross-Section
Unknown! Deteremined from
hadron-hadron collisions.
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Quark Fragmentation Functions
determined from e+e- annihilations
Page 5
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.
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Quark Fragmentation Functions
determined from e+e- annihilations
Page 6
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 π0’s!
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 7
Feynman Talk at Coral Gables
(December 1976)
1st transparency
Last transparency
“Feynman-Field
Jet Model”
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 8
QCD Approach: Quarks & Gluons
Quark & Gluon Fragmentation
Functions
Q2 dependence predicted from QCD
FFF2 1978
Parton Distribution Functions
Q2 dependence predicted from
QCD
Quark & Gluon Cross-Sections
Calculated from QCD
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 9
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
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 10
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(η
η)dη
η be the probability that the rank 1 meson leaves
fractional momentum η to the remaining cascade, leaving
Rank 2
Rank 1
quark “b” with momentum P1 = η1P0.
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(η
η)), leaving quark
“c” with momentum P2 = η2P1 = η2η1P0.
cc pair bb pair
Calculate F(z)
from f(η
η) and βi!
Original quark with
flavor “a” and
momentum P0
Fermilab Energy Scaling Workshop
April 27, 2009
Add in flavor dependence by letting βu = probabliity of
producing u-ubar pair, βd = 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 11
Feynman-Field Jet Model
R. P. Feynman
ISMD, Kaysersberg,
France, June 12, 1977
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 12
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, ....”
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 13
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.”
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 14
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%!!
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 15
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
Fermilab Energy Scaling Workshop
April 27, 2009
PYTHIA 6.4
Rick Field – Florida/CDF/CMS
HERWIG++
Page 16
The Fermilab Tevatron
CDF “SciCo” Shift December 12-19, 2008
Proton
CDF
1 mile
AntiProton
Proton
2 TeV
I joined CDF in January 1998.
Fermilab Energy Scaling Workshop
April 27, 2009
AntiProton
Acquired 4728 nb-1 during
8 hour “owl” shift!
Rick Field – Florida/CDF/CMS
Page 17
The Fermilab Tevatron
CDF “SciCo” Shift December 12-19, 2008
My wife Jimmie on shift with me!
Proton
CDF
1 mile
AntiProton
Proton
2 TeV
I joined CDF in January 1998.
Fermilab Energy Scaling Workshop
April 27, 2009
AntiProton
Acquired 4728 nb-1 during
8 hour “owl” shift!
Rick Field – Florida/CDF/CMS
Page 18
Proton-AntiProton Collisions
at the Tevatron
Elastic Scattering
The CDF “Min-Bias” trigger
picks up most of the “hard
core” cross-section plus a
Double
Diffraction
small
amount of single &
double diffraction.
M2
M1
Single Diffraction
M
σtot = σEL + σSD + σDD + σHC
1.8 TeV: 78mb
= 18mb
The “hard core” component
contains both “hard” and
“soft” collisions.
+ 9mb
+ (4-7)mb + (47-44)mb
CDF “Min-Bias” trigger
1 charged particle in forward BBC
AND
1 charged particle in backward BBC
Hard Core
“Inelastic Non-Diffractive Component”
“Hard” Hard Core (hard scattering)
Outgoing Parton
“Soft” Hard Core (no hard scattering)
Proton
AntiProton
PT(hard)
Beam-Beam Counters
3.2 < |η
η| < 5.9
Proton
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
Final-State
Radiation
Outgoing Parton
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 19
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!
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 20
Particle Densities
2π
π
∆η∆φ = 4π
π = 12.6
φ
31 charged
charged particles
particle
Charged Particles
pT > 0.5 GeV/c |η
η| < 1
CDF Run 2 “Min-Bias”
CDF Run 2 “Min-Bias”
Observable
Average
Average Density
per unit η-φ
φ
Nchg
Number of Charged Particles
η| < 1)
(pT > 0.5 GeV/c, |η
3.17 +/- 0.31
0.252 +/- 0.025
PTsum
(GeV/c)
Scalar pT sum of Charged Particles
η| < 1)
(pT > 0.5 GeV/c, |η
2.97 +/- 0.23
0.236 +/- 0.018
chg/dη
3/4π
0.24
dNchg
ηηdφ
φφ = 1/4π
ππ = 0.08
13 GeV/c PTsum
0
-1
η
+1
Divide by 4π
π
dPTsum/dη
ηdφ
φ = 1/4π
3/4π
π GeV/c = 0.08
0.24 GeV/c
Study the charged particles (pT > 0.5 GeV/c, |η
η| < 1) and form the charged
ηdφ
φ, and the charged scalar pT sum density,
particle density, dNchg/dη
dPTsum/dη
ηdφ
φ.
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 21
CDF Run 1: Evolution of Charged Jets
“Underlying Event”
Charged Particle ∆φ Correlations
PT > 0.5 GeV/c |η
η| < 1
Charged Jet #1
Direction
“Transverse” region
very sensitive to the
“underlying event”!
Look at the charged
particle density in the
“transverse” region!
2π
π
CDF Run 1 Analysis
Away Region
Charged Jet #1
Direction
∆φ
Transverse
Region
“Toward-Side” Jet
∆φ
“Toward”
“Toward”
“Transverse”
φ
Leading
Jet
“Transverse”
Toward Region
“Transverse”
“Transverse”
Transverse
Region
“Away”
“Away”
Away Region
“Away-Side” Jet
0
-1
η
+1
Look at charged particle correlations in the azimuthal angle ∆φ relative to the leading charged
particle jet.
o
o
o
o
Define |∆φ
∆φ|
∆φ|
∆φ|
∆φ < 60 as “Toward”, 60 < |∆φ
∆φ < 120 as “Transverse”, and |∆φ
∆φ > 120 as “Away”.
o
All three regions have the same size in η-φφ space, ∆ηx∆φ
π/3.
∆η ∆φ = 2x120 = 4π
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 22
Run 1 Charged Particle Density
“Transverse” pT Distribution
ηdφ
φ
"Transverse" Charged Particle Density: dN/dη
Charged Particle Jet #1
Direction
∆φ
"Transverse" Charged Density
1.00
CDF Min-Bias
CDF JET20
CDF Run 1
data uncorrected
0.75
“Toward”
0.50
Factor of 2!
“Transverse”
0.25
“Transverse”
1.8 TeV |η
η|<1.0 PT>0.5 GeV/c
“Away”
0.00
0
5
10
15
20
25
30
35
40
45
50
PT(charged jet#1) (GeV/c)
“Min-Bias”
Compares the average “transverse” charge particle density with the average “Min-Bias”
charge particle density (|η
η|<1, pT>0.5 GeV). Shows how the “transverse” charge particle
density and the Min-Bias charge particle density is distributed in pT.
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 23
Run 1 Charged Particle Density
“Transverse” pT Distribution
ηdφ
φ
"Transverse" Charged Particle Density: dN/dη
Charged Particle Density
1.0E+00
CDF Min-Bias
CDF JET20
CDF Run 1
data uncorrected
0.50
Factor of 2!
0.25
1.8 TeV |η
η|<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/dη
ηdφ
φ> = 0.56
“Min-Bias”
CDF Run 1
"Transverse"
PT(chgjet#1) > 5 GeV/c
0.75
50
Charged Density dN/dη dφdPT (1/GeV/c)
"Transverse" Charged Density
1.00
data uncorrected
1.0E-01
"Transverse"
PT(chgjet#1) > 30 GeV/c
1.0E-02
1.0E-03
1.0E-04
Min-Bias
1.0E-05
1.8 TeV |η
η |<1 PT>0.5 GeV/c
1.0E-06
CDF Run 1 Min-Bias data
<dNchg/dη
ηdφ
φ> = 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 (|η
η|<1, pT>0.5 GeV). Shows how the “transverse” charge particle
density and the Min-Bias charge particle density is distributed in pT.
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 24
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).
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 25
Tuning PYTHIA:
Multiple Parton Interaction Parameters
Parameter
Default
PARP(83)
0.5
PARP(84)
0.2
Description
Double-Gaussian: Fraction of total hadronic
matter within PARP(84)
Hard
Core
Double-Gaussian: Fraction of the overall hadron
radius containing the fraction PARP(83) of the
total hadronic matter.
Multiple Parton Interaction
Color String
Color String
PARP(86)
0.33
0.66
PARP(89)
1 TeV
PARP(90)
0.16
PARP(67)
1.0
Probability that the MPI produces two gluons
with color connections to the “nearest neighbors.
Multiple PartonDetermine
Interactionby comparing
with 630 GeV data!
Probability that the MPI produces two gluons
either as described by PARP(85) or as a closed
gluon
loop.
remaining
fraction consists of
Affects
the The
amount
of
quark-antiquark
pairs.
initial-state radiation!
Color String
Hard-Scattering Cut-Off PT0
5
Determines the reference energy E0.
Determines the energy dependence of the cut-off
PT0 as follows PT0(Ecm) = PT0(Ecm/E0)ε with
ε = PARP(90)
A scale factor that determines the maximum
parton virtuality for space-like showers. The
larger the value of PARP(67) the more initialstate radiation.
PYTHIA 6.206
ε = 0.25 (Set A))
4
PT0 (GeV/c)
PARP(85)
Take E0 = 1.8 TeV
3
2
ε = 0.16 (default)
1
100
1,000
10,000
100,000
CM Energy W (GeV)
Reference point
at 1.8 TeV
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 26
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
ηdφ
φ
"Transverse" Charged Particle Density: dN/dη
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 |η
η|<1.0 PT>0.5 GeV
0.00
0
5
10
15
20
25
30
35
40
45
50
PT(charged jet#1) (GeV/c)
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)
Fermilab Energy Scaling Workshop
April 27, 2009
Default parameters give
very poor description of
the “underlying event”!
Rick Field – Florida/CDF/CMS
Page 27
Run 1 PYTHIA Tune A
CDF Default!
PYTHIA 6.206 CTEQ5L
"Transverse" Charged Particle Density: dN/dη
ηdφ
φ
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
PARP(86)
1.0
0.95
PARP(89)
1.8 TeV
1.8 TeV
PARP(90)
0.25
0.25
PARP(67)
1.0
4.0
"Transverse" Charged Density
1.00
CDF Preliminary
0.75
Fermilab Energy Scaling Workshop
April 27, 2009
Run 1 Analysis
0.50
0.25
CTEQ5L
PYTHIA 6.206 (Set B)
PARP(67)=1
1.8 TeV |η
η|<1.0 PT>0.5 GeV
0.00
0
New PYTHIA default
(less initial-state radiation)
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 28
PYTHIA Tune A Min-Bias
“Soft” + ”Hard”
Tuned to fit the CDF Run 1
“underlying event”!
PYTHIA Tune A
CDF Run 2 Charged
Default
Particle Density
Charged Particle Density: dN/dη
ηdφ
φ
1.0
CDF Published
1.0E+00
Pythia 6.206 Set A
CDF Min-Bias Data
1.0E-01
0.6
0.4
0.2
Pythia 6.206 Set A
CDF Min-Bias 1.8 TeV
1.8 TeV all PT
0.0
-4
-3
-2
-1
0
1
2
3
4
Pseudo-Rapidity η
PYTHIA regulates the perturbative 2-to-2
Charged Density dN/dη dφ dPT (1/GeV/c)
dN/d η dφ
0.8
1.8 TeV |η
η|<1
1.0E-02
12% of “Min-Bias” events
have PT(hard) > 5 GeV/c!
PT(hard) > 0 GeV/c
1.0E-03
1.0E-04
1% of “Min-Bias” events
have PT(hard) > 10 GeV/c!
1.0E-05
CDF Preliminary
parton-parton cross sections with cut-off
1.0E-06
parameters
which allows one to run with
Lots of “hard” scattering in
0
2
4
6
8
10
12
PT“Min-Bias”
(hard) > at
0. the
One
can simulate both “hard”
Tevatron!
PT(charged) (GeV/c)
and “soft” collisions in one program.
The relative amount of “hard” versus “soft” depends on the cut-off and can be tuned.
14
This PYTHIA fit predicts that 12% of all “Min-Bias” events are a result of a hard 2-to-2
parton-parton scattering with PT(hard) > 5 GeV/c (1% with PT(hard) > 10 GeV/c)!
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 29
PYTHIA Tune A
LHC Min-Bias Predictions
Hard-Scattering in Min-Bias Events
Charged Particle Density
50%
12% of “Min-Bias”
events
have|ηη|<1
PT(hard) > 10 GeV/c!
1.0E+00
Pythia 6.206 Set A
Pythia 6.206 Set A
40%
% of Events
Charged Density dN/dη dφ dPT (1/GeV/c)
1.0E-01
1.0E-02
PT(hard) > 5 GeV/c
PT(hard) > 10 GeV/c
30%
20%
1.8 TeV
1.0E-03
10%
14 TeV
1.0E-04
0%
100
1,000
10,000
100,000
CM Energy W (GeV)
630 GeV
LHC?
1.0E-05
CDF Data
Shows the center-of-mass energy dependence
1.0E-06
0
2
4
6
8
PT(charged) (GeV/c)
1% of “Min-Bias” events
have PT(hard) > 10 GeV/c!
10
12
14
of the charged particle density,
dNchg/dη
ηdφ
φdPT, for “Min-Bias” collisions
compared with PYTHIA Tune A with
PT(hard) > 0.
PYTHIA Tune A predicts that 1% of all “Min-Bias” events at 1.8 TeV are a result of a hard
2-to-2 parton-parton scattering with PT(hard) > 10 GeV/c which increases to 12% at 14 TeV!
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 30
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 αs for space-like showers is scaled by PARP(64)!
Fermilab Energy Scaling Workshop
April 27, 2009
20
Rick Field – Florida/CDF/CMS
Page 31
Jet-Jet Correlations (DØ)
Jet#1-Jet#2 ∆φ Distribution
∆φ 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).
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 32
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
CDF Run 1
published
HERWIG
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!
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 33
All use LO αs
with Λ = 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
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 34
All use LO αs
with Λ = 192 MeV!
PYTHIA 6.2 Tunes
UE Parameters
Tune ISR
A Parameter
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!
PARP(86)There 1.0
1.0
0.66 by
are new 6.420
tunes
PARP(89)
1.96 TeV
TeV
1.0 TeV
Peter Skands
(Tune1.96S320,
update
of S0)
PARP(90)
0.16
0.16
Peter Skands
(Tune
N324,0.16N0CR)
PARP(62)
1.25
1.0
Hendrik
Hoeth
(Tune1.25P329, “Professor”)
PARP(64)
0.2
0.2
1.0
PARP(67)
2.5
2.5
1.0
MSTP(91)
1
1
1
PARP(91)
PARP(93)
Tune 2.1
DW
15.0
2.1
15.0
Tune D
Tune D6T
Intrinsic KT
Fermilab Energy Scaling Workshop
April 27, 2009
1.0
Tune
D6
5.0
Rick Field – Florida/CDF/CMS
Page 35
JIMMY at CDF
PT(JIM)= 2.5 GeV/c.
The Energy in the “Underlying
Event” in High PT Jet Production
Jet #1 Direction
JIMMY: MPI
J. M. Butterworth
J. R. Forshaw
M. H. Seymour
∆φ
“Toward”
“Transverse”
PT(JIM)= 3.25 GeV/c.
“Transverse”
"Transverse" ETsum Density: dET/dη
ηdφ
φ
4.0
"Transverse" ETsum Density (GeV)
JIMMY
Runs with HERWIG and adds
multiple parton interactions!
JIMMY was tuned to fit
the energy density in the
“transverse” region for
“leading jet” events!
JIMMY Default
1.96 TeV
HW
3.0
2.0
PY Tune A
JM325
"Leading Jet"
1.0
MidPoint R = 0.7 |η
η(jet)| < 2
CDF Run 2 Preliminary
The Drell-Yan JIMMY Tune
PTJIM = 3.6 GeV/c,
PT(particle jet#1) (GeV/c)
JMRAD(73) = 1.8
"Transverse" PTsum Density: dPT/dη
ηdφ
φ
JMRAD(91) = 1.8
All Particles (|η
η|<1.0)
generator level theory
0.0
0
“Away”
Outgoing Parton
Initial-State Radiation
AntiProton
Underlying Event
Outgoing Parton
Underlying Event
Final-State
Radiation
"Transverse" PTsum Density (GeV/c)
1.6
PT(hard)
Proton
100
200
300
400
500
JIMMY Default
1.96 TeV
1.2
JM325
PY Tune A
0.8
"Leading Jet"
HW
0.4
MidPoint R = 0.7 |η
η(jet)| < 2
CDF Run 2 Preliminary
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
generator level theory
0.0
0
50
“Transverse” <Densities> vs PT(jet#1)
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
100
150
200
250
300
350
400
450
500
PT(particle jet#1) (GeV/c)
Page 36
Min-Bias “Associated”
Charged Particle Density
Highest pT
charged particle!
ηdφ
φ
Charged Particle Density: dN/dη
“Associated” densities do
not include PTmax!
0.5
PTmax Direction
∆φ
Correlations in φ
Charged Particle Density
CDF Preliminary
Associated Density
PTmax not included
data uncorrected
0.4
Charge Density
0.3
0.2
0.1
Charged Particles
(|η
η|<1.0, PT>0.5 GeV/c)
PTmax
Min-Bias
0.0
0
30
60
90
120
150
180
210
240
270
300
330
360
∆φ (degrees)
Use the maximum pT charged particle in the event, PTmax, to define a direction and look
at the the “associated” density, dNchg/dη
ηdφ
φ, in “min-bias” collisions (pT > 0.5 GeV/c, |η
η| <
1).
Shows the data on the ∆φ dependence of the “associated” charged particle density,
dNchg/dη
ηdφ
φ, for charged particles (pT > 0.5 GeV/c, |η
η| < 1, not including PTmax) relative
o
to PTmax (rotated to 180 ) for “min-bias” events. Also shown is the average charged
particle density, dNchg/dη
ηdφ
φ, for “min-bias” events.
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 37
Min-Bias “Associated”
Charged Particle Density
Highest pT
charged particle!
ηdφ
φ
Charged Particle Density: dN/dη
“Associated” densities do
not include PTmax!
0.5
PTmax Direction
∆φ
Correlations in φ
Charged Particle Density
CDF Preliminary
Associated Density
PTmax not included
data uncorrected
0.4
Charge Density
0.3
0.2
0.1
Charged Particles
(|η
η|<1.0, PT>0.5 GeV/c)
PTmax
Min-Bias
0.0
0
30
60
90
120
150
180
210
240
270
300
330
360
∆φ (degrees)
Use the maximum pT charged particle in the event, PTmax, to define a direction and look
It is more probable
to find
aηdφ
particle
at the the “associated”
density, dN
chg/dη
φ, in “min-bias” collisions (pT > 0.5 GeV/c, |η
η| <
accompanying
PTmax
than
it
is
to
1).
find a particle in the central region!
Shows the data
on the ∆φ dependence of the “associated” charged particle density,
dNchg/dη
ηdφ
φ, for charged particles (pT > 0.5 GeV/c, |η
η| < 1, not including PTmax) relative
o
to PTmax (rotated to 180 ) for “min-bias” events. Also shown is the average charged
particle density, dNchg/dη
ηdφ
φ, for “min-bias” events.
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 38
Min-Bias “Associated”
Charged Particle Density
Rapid rise in the particle
density in the “transverse”
region as PTmax increases!
ηdφ
φ
Associated Particle Density: dN/dη
PTmaxDirection
Direction
PTmax
Jet #1
∆φ
“Toward”
“Transverse”
“Transverse”
Correlations in φ
“Away”
PTmax > 2.0 GeV/c
Associated Particle Density
∆φ
PTmax > 2.0 GeV/c
1.0
Charged Particles
(|η
η|<1.0, PT>0.5 GeV/c)
PTmax > 1.0 GeV/c
0.8
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
∆φ (degrees)
Ave Min-Bias
0.25 per unit η-φ
φ
PTmax > 0.5 GeV/c
Shows the data on the ∆φ dependence of the “associated” charged particle density,
dNchg/dη
ηdφ
φ, for charged particles (pT > 0.5 GeV/c, |η
η| < 1, not including PTmax) relative
o
to PTmax (rotated to 180 ) 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!).
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 39
Min-Bias “Associated”
Charged PTsum Density
Highest pT
charged particle!
ηdφ
φ
Charged PTsum Density: dPT/dη
PTmax Direction
Correlations in φ
0.5
Charged PTsum Density (GeV/c)
∆φ
“Associated” densities do
not include PTmax!
CDF Preliminary
Associated Density
PTmax not included
data uncorrected
0.4
PTsum Density
0.3
0.2
0.1
Charged Particles
(|η
η|<1.0, PT>0.5 GeV/c)
PTmax
Min-Bias
0.0
0
30
60
90
120
150
180
210
240
270
300
330
360
∆φ (degrees)
Use the maximum pT charged particle in the event, PTmax, to define a direction and look
at the the “associated” PTsum density, dPTsum/dη
ηdφ
φ.
Shows the data on the ∆φ dependence of the “associated” charged PTsum density,
dPTsum/dη
ηdφ
φ, for charged particles (pT > 0.5 GeV/c, |η
η| < 1, not including PTmax) relative
o
to PTmax (rotated to 180 ) for “min-bias” events. Also shown is the average charged
particle density, dPTsum/dη
ηdφ
φ, for “min-bias” events.
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 40
Min-Bias “Associated”
Charged PTsum Density
Rapid rise in the PTsum
density in the “transverse”
region as PTmax increases!
PTmaxDirection
Direction
PTmax
Jet #1
∆φ
∆φ
“Toward”
“Transverse”
“Transverse”
Correlations in φ
“Away”
Jet #2
Associated PTsum Density (GeV/c)
ηdφ
φ
Associated PTsum Density: dPT/dη
1.0
PTmax > 2.0 GeV/c
CDF Preliminary
PTmax > 1.0 GeV/c
0.8
data uncorrected
PTmax > 0.5 GeV/c
Transverse
Region
0.6
Charged Particles
(|η
η|<1.0, PT>0.5 GeV/c)
Transverse
Region
0.4
0.2
PTmax
Min-Bias
PTmax not included
0.0
0
30
60
90
120
150
180
210
240
270
300
330
360
∆φ (degrees)
Ave Min-Bias
0.24 GeV/c per unit η-φ
φ
Shows the data on the ∆φ dependence of the “associated” charged PTsum density,
dPTsum/dη
ηdφ
φ, for charged particles (pT > 0.5 GeV/c, |η
η| < 1, not including PTmax) relative
o
to PTmax (rotated to 180 ) 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!).
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 41
Min-Bias “Associated”
Charged Particle Density
PY Tune A
PTmax > 2.0 GeV/c
∆φ
“Toward”
“Transverse”
“Transverse”
Correlations in φ
“Away”
Associated Particle Density
PTmax Direction
Direction
PTmax
∆φ
ηdφ
φ
Associated Particle Density: dN/dη
1.0
0.8
PTmax > 2.0 GeV/c
PY Tune A
CDF Preliminary
PTmax > 0.5 GeV/c
data uncorrected
theory + CDFSIM
PY Tune A
Transverse
Region
0.6
PY Tune A 1.96 TeV
Transverse
Region
0.4
0.2
PTmax
PTmax not included
(|η
η|<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
∆φ (degrees)
Shows the data on the ∆φ dependence of the “associated” charged particle density,
dNchg/dη
ηdφ
φ, for charged particles (pT > 0.5 GeV/c, |η
η| < 1, not including PTmax) relative
o
to PTmax (rotated to 180 ) 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”).
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 42
Min-Bias “Associated”
Charged PTsum Density
PY Tune A
PTmax Direction
Direction
PTmax
∆φ
∆φ
“Toward”
“Transverse”
“Transverse”
Correlations in φ
“Away”
Associated PTsum Density (GeV/c)
PTmax > 2.0 GeV/c
ηdφ
φ
Associated PTsum Density: dPT/dη
1.0
PTmax > 2.0 GeV/c
PY Tune A
0.8
PTmax > 0.5 GeV/c
0.6
PY Tune A
Transverse
Region
CDF Preliminary
data uncorrected
theory + CDFSIM
PY Tune A 1.96 TeV
Transverse
Region
0.4
0.2
PTmax
(|η
η|<1.0, PT>0.5 GeV/c)
PTmax not included
0.0
0
30
60
90
120
PTmax > 0.5 GeV/c
150
180
210
240
270
300
330
360
∆φ (degrees)
Shows the data on the ∆φ dependence of the “associated” charged PTsum density,
dPTsum/dη
ηdφ
φ, for charged particles (pT > 0.5 GeV/c, |η
η| < 1, not including PTmax) relative
o
to PTmax (rotated to 180 ) 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”).
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 43
Min-Bias “Associated”
Charged Particle Density
PTmax Direction
Associated Charged Particle Density: dN/dη
ηdφ
φ
∆φ
10.0
Charged Particle Density
RDF Preliminary
py Tune A generator level
“Toward” Region
“Toward”
PTmax > 2.0 GeV/c
PTmax > 5.0 GeV/c
1.0
PTmax > 10.0 GeV/c
“Transverse”
“Transverse”
“Transverse”
“Transverse”
“Away”
0.1
Min-Bias
1.96 TeV
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
0.0
0
30
60
PTmax > 0.5 GeV/c
PTmax > 1.0 GeV/c
90
120
150
180
210
240
270
300
330
360
∆φ (degrees)
Shows the ∆φ dependence of the “associated” charged particle density, dNchg/dη
ηdφ
φ, for charged
particles (pT > 0.5 GeV/c, |η
η| < 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
∆φ
“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, |η
η| < 1, not including PTmax) for “min-bias” events at 1.96 TeV from
PYTHIA Tune A (generator level).
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 44
Min-Bias “Associated”
Charged Particle Density
PTmax Direction
ηdφ
φ
Associated Charged Particle Density: dN/dη
∆φ
Associated Charged Particle Density: dN/dη
ηdφ
φ
10.0
1.6
py Tune A generator level
“Toward” Region
RDF Preliminary
PTmax > 2.0 GeV/c
PTmax > 5.0 GeV/c
1.0
PTmax > 10.0 GeV/c
Charged Particle Density
Charged Particle Density
RDF Preliminary
“Transverse”
“Transverse”
0.1
Min-Bias
1.96 TeV
PTmax > 0.5 GeV/c
PTmax > 1.0 GeV/c
py Tune A generator level
1.2
Min-Bias
1.96 TeV
“Toward”
"Toward"
“Transverse”
“Transverse”
"Away"
0.8
"Transverse"
“Away”
0.4
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
0.0
0.0
0
30
60
90
120
150
180
210
240
270
300
330
360
0
2
∆φ (degrees)
4
6
8
10
12
14
16
18
PTmax (GeV/c)
Shows the ∆φ dependence of the “associated” charged particle density, dNchg/dη
ηdφ
φ, for charged
particles (pT > 0.5 GeV/c, |η
η| < 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
∆φ
“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, |η
η| < 1, not including PTmax) for “min-bias” events at 1.96 TeV from
PYTHIA Tune A (generator level).
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 45
20
Min-Bias “Associated”
Charged Particle Density
PTmax Direction
Associated Charged
Charged Particle
Particle Density:
Density: dN/dη
dN/dη
dφ
Associated
ηηdφ
φφ
∆φ
Associated Charged Particle Density: dN/dη
ηdφ
φ
10.0
1.6
2.5
py Tune A generator level
“Toward” Region
PTmax > 2.0 GeV/c
PTmax > 5.0 GeV/c
1.0
RDF
RDF Preliminary
Preliminary
PTmax > 10.0 GeV/c
Charged Particle Density
Charged Particle Density
RDF Preliminary
“Transverse”
“Transverse”
0.1
Min-Bias
1.96 TeV
PTmax > 0.5 GeV/c
PTmax > 1.0 GeV/c
py Tune A generator level
py Tune A generator level
2.0
1.2
Min-Bias
Min-Bias
14 TeV
1.96 TeV
“Toward”
"Toward"
"Away"
"Toward"
“Transverse”
1.5
“Transverse”
"Away"
0.8
"Transverse"
"Transverse"
1.0
“Away”
0.4
0.5
Charged
ηη|<1.0,
ChargedParticles
Particles(|η
(|η
|<1.0,PT>0.5
PT>0.5GeV/c)
GeV/c)
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
0.0
0.0
0.0
0
30
60
90
120
150
180
210
240
270
300
330
360
00
2
∆φ (degrees)
54
6
10
8
10
15
12
14
20
16
18
PTmax
PTmax (GeV/c)
(GeV/c)
Shows the ∆φ dependence of the “associated” charged particle density, dNchg/dη
ηdφ
φ, for charged
particles (pT > 0.5 GeV/c, |η
η| < 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
∆φ
“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, |η
η| < 1, not including PTmax) for “min-bias” events at 1.96 TeV from
PYTHIA Tune A (generator level).
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 46
25
20
Min-Bias “Associated”
Charged Particle Density
PTmax Direction
Associated Charged
Charged
Particle
Density:
dN/dη
dφ
Associated
ηηηdφ
φφφ
"Transverse"
ChargedParticle
ParticleDensity:
Density:dN/dη
dN/dη
dφ
∆φ
Associated Charged Particle Density: dN/dη
ηdφ
φ
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 (|η
η|<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
1.96 TeV
"Transverse"
"Transverse"
1.0
0.4
0.4
0.5
0.2
“Away”
Charged
ηη|<1.0,
ChargedParticles
Particles(|η
(|η
|<1.0,PT>0.5
PT>0.5GeV/c)
GeV/c)
Charged Particles (|η
η|<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
∆φ (degrees)
54
6
10
8
10
15
12
14
20
16
18
PTmax (GeV/c)
(GeV/c)
PTmax
Shows the ∆φ dependence of the “associated” charged particle density, dNchg/dη
ηdφ
φ, for charged
particles (pT > 0.5 GeV/c, |η
η| < 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
∆φ
“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, |η
η| < 1, not including PTmax) for “min-bias” events at 1.96 TeV from
PYTHIA Tune A (generator level).
Fermilab Energy Scaling Workshop
April 27, 2009
Rick Field – Florida/CDF/CMS
Page 47
25
20
25
1st Workshop on Energy Scaling
in Hadron-Hadron Collisions
Rick Field Talk 2 Tomorrow at 1:30pm
From Min-Bias to the Underlying Event
Comparing with the
630 GeV data
CDF Run 2 Underlying
Event Studies
Rick Field Talk 3 Wednesday at 9:00am
From CDF to CMS
Extrapolating to the
LHC
Fermilab Energy Scaling Workshop
April 27, 2009
Tune S320 and P329
compared with Tune A,
DW, and DWT
Rick Field – Florida/CDF/CMS
Page 48