Workshop on Early Physics
Opportunities at the LHC
“Min-Bias” and the “Underlying Event”
Rick Field
University of Florida
Outline of Talk
¨ The QCD Monte-Carlo Model tunes.
LBNL May 6, 2009
Outgoing Parton
¨ The Pythia MPI energy scaling
PT(hard)
Initial-State Radiation
parameter PARP(90).
Proton
AntiProton
Underlying Event
¨ “Min-Bias” and the “underlying
event” at the LHC.
Outgoing Parton
¨ The “underlying event” in Drell-Yan
Underlying Event
Final-State
Radiation
lepton-pair production.
¨ LHC predictions!
¨ Summary & Conclusions.
¨ Early LHC Thesis Projects.
Workshop on Early LHC Physics
May 6, 2009
CDF Run 2
Rick Field – Florida/CDF/CMS
CMS at the LHC
Page 1
QCD Monte-Carlo Models:
High Transverse Momentum Jets
Hard Scattering
Initial-State Radiation
Hard Scattering “Jet”
Initial-State Radiation
“Jet”
Outgoing Parton
PT(hard)
Outgoing Parton
PT(hard)
Proton
“Hard Scattering” Component
AntiProton
Final-State Radiation
Outgoing Parton
Underlying Event
Underlying Event
Proton
“Jet”
Final-State Radiation
AntiProton
Underlying Event
Outgoing Parton
Underlying Event
“Underlying Event”
¨ Start with the perturbative 2-to-2 (or sometimes 2-to-3) parton-parton scattering and add initial and finalstate gluon radiation (in the leading log approximation or modified leading log approximation).
¨ The “underlying event” consists of the “beam-beam remnants” and from particles arising from soft or
semi-soft multiple parton interactions (MPI).
The “underlying
event” is“jet”
an unavoidable
¨ Of course the outgoing colored partons fragment
into hadron
and inevitably “underlying event”
background to most collider observables
observables receive contributions from initial
and final-state radiation.
and having good understand of it leads to
more precise collider measurements!
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 2
QCD Monte-Carlo Models:
Lepton-Pair Production
Lepton-Pair
Production
High
PT Z-Boson
Production
Anti-Lepton
Outgoing Parton
Initial-State
Initial-State Radiation
Radiation
High Lepton-Pair
PT Z-Boson Production
Production
Initial-State
Initial-StateRadiation
Radiation
“Jet”
Proton
Proton
Final-State Radiation
Outgoing
Parton
Anti-Lepton
Final-State Radiation
“Hard Scattering” Component
AntiProton
AntiProton
Underlying Event
Lepton
Z-boson
Underlying Event
Proton
Lepton
Z-boson
Underlying Event
AntiProton
Underlying Event
“Underlying Event”
¨ Start with the perturbative Drell-Yan muon pair production and add initial-state gluon radiation (in the
leading log approximation or modified leading log approximation).
¨ The “underlying event” consists of the “beam-beam remnants” and from particles arising from soft or
semi-soft multiple parton interactions (MPI).
¨ Of course the outgoing colored partons fragment into hadron “jet” and inevitably “underlying event”
observables receive contributions from initial-state radiation.
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 3
Tuning PYTHIA:
Multiple Parton Interaction Parameters
Parameter
Default
Description
PARP(83)
0.5
Double-Gaussian: Fraction of total hadronic
matter within PARP(84)
PARP(84)
0.2
Double-Gaussian: Fraction of the overall hadron
radius containing the fraction PARP(83) of the
total hadronic matter.
Core
Hard
Multiple Parton Interaction
Color String
Color String
PARP(86)
PARP(89)
PARP(90)
PARP(67)
0.33
0.66
1 TeV
0.16
1.0
Probability that the MPI produces two gluons
with color connections to the “nearest neighbors.
Multiple PartonDetermine
Interactionby comparing
with 630 GeV data!
Probability that the MPI produces two gluons
either as described by PARP(85) or as a closed
gluon
loop.
remaining
fraction consists of
Affects
the The
amount
of
quark-antiquark
pairs.
initial-state radiation!
Color String
Hard-Scattering Cut-Off PT0
5
Determines the reference energy E0.
Determines the energy dependence of the cut-off
PT0 as follows PT0(Ecm) = PT0(Ecm/E0)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
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 4
“Transverse” Cones
vs “Transverse” Regions
“Cone Analysis”
2π
Transverse
Cone:
π(0.7)2=0.49π
Away Region
Transverse
Region
φ
(Tano, Kovacs, Huston, Bhatti)
Cone 1
φ
Leading
Jet
PT90 (GeV/c)
2π
MAX Data
CDF PRELIMINARY
MAX Herwig+QFL
MAX Pythia6.115+QFL (tuned)
MIN Data
MIN Herwig+QFL
MIN Pythia6.115+QFL (tuned)
5
Leading
Jet
4
Toward Region
Transverse
Region:
2π/3=0.67π
Transverse
Region
6
Cone 2
3
Away Region
0
0
-1
η
+1
-1
η
+1
¨ Sum the PT of charged particles in two cones of radius
0.7 at the same η as the leading jet but with |ΔΦ| = 90o.
¨ Plot the cone with the maximum and minimum PTsum
versus the ET of the leading (calorimeter) jet.
2
1
0
50
100
150
200
250
ET of leading jet (GeV)
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 5
CDF PRELIMINARY
2.5
2
MAX Data
MAX Herwig+QFL
MAX Pythia6.115+QFL (tuned)
MIN Data
MIN Herwig+QFL
MIN Pythia6.115+QFL (tuned)
“Cone Analysis”
PT90 (GeV/c)
PT90 (GeV/c)
Energy Dependence
of the “Underlying Event”
6
(Tano, Kovacs, Huston, Bhatti)
630 GeV
1,800 GeV
5
MAX Data
CDF PRELIMINARY
MAX Herwig+QFL
MAX Pythia6.115+QFL (tuned)
MIN Data
MIN Herwig+QFL
MIN Pythia6.115+QFL (tuned)
4
1.5
3
PYTHIA 6.115
PT0 = 1.4 GeV
1
0.5
PYTHIA 6.115
PT0 = 2.0 GeV
20
30
40
50
60
70
2
1
80
ET of leading Jet (GeV)
0
50
100
150
200
250
ET of leading jet (GeV)
¨ Sum the PT of charged particles (pT > 0.4 GeV/c) in two cones of radius 0.7 at the same η as the leading
jet but with |ΔΦ| = 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 ε = 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/dηdφ = 0.16 GeV/c
and 1.4 GeV/c in the MAX cone implies dPTsum/dηdφ = 0.91 GeV/c (average PTsum density of 0.54
GeV/c per unit η-φ).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 6
“Transverse” Charged Densities
Energy Dependence
"Transverse" Charged PTsum Density: dPTsum/dηdφ
"Min Transverse" PTsum Density: dPTsum/dηdφ
0.60
0.3
Charged PTsum Density (GeV)
Charged PTsum Density (GeV)
ε = 0.25
HERWIG 6.4
0.40
ε = 0.16
0.20
ε=0
CTEQ5L
Pythia 6.206 (Set A)
630 GeV |η|<1.0 PT>0.4 GeV
Pythia 6.206 (Set A)
HERWIG 6.4
ε = 0.25
0.2
0.1
CTEQ5L
ε = 0.16
ε=0
630 GeV |η|<1.0 PT>0.4 GeV
0.0
0.00
0
5
10
15
20
25
30
35
40
45
50
0
5
10
20
25
30
35
40
45
50
PT(charged jet#1) (GeV/c)
PT(charged jet#1) (GeV/c)
¨ Shows the “transverse” charged PTsum density
Hard-Scattering Cut-Off PT0
5
PYTHIA 6.206
ε = 0.25 (Set A))
4
PT0 (GeV/c)
(|η|<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, ε = 0, ε =
0.16 (default) and ε = 0.25 (preferred)).
¨ Also shown are the PTsum densities (0.16 GeV/c and
0.54 GeV/c) determined from the Tano cone
analysis at 630 GeV
Workshop on Early LHC Physics
May 6, 2009
15
3
2
ε = 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 7
“Transverse” Charged Densities
Energy Dependence
"Transverse" Charged PTsum Density: dPTsum/dηdφ
"Min Transverse" PTsum Density: dPTsum/dηdφ
0.60
0.3
Charged PTsum Density (GeV)
Charged PTsum Density (GeV)
ε = 0.25
HERWIG 6.4
0.40
ε = 0.16
0.20
ε=0
HERWIG 6.4
ε = 0.25
0.2
0.1
Increasing ε produces less energy
dependence for the
UE resulting
in
ε = 0.16
ε=0
less UE activity at the LHC!
CTEQ5L
Pythia 6.206 (Set A)
Pythia 6.206 (Set A)
630 GeV |η|<1.0 PT>0.4 GeV
CTEQ5L
630 GeV |η|<1.0 PT>0.4 GeV
0.0
0.00
0
5
10
15
20
25
30
35
40
45
50
0
5
10
20
25
30
35
40
45
50
PT(charged jet#1) (GeV/c)
PT(charged jet#1) (GeV/c)
Lowering PT0 at 630 GeV (i.e.
increasing
ε) increases
charged
PTsum
densityUE activity
resulting in less energy dependence.
(|η|<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, ε = 0, ε =
0.16 (default) and ε = 0.25 (preferred)).
¨ Also shown are the PTsum densities (0.16 GeV/c and
0.54 GeV/c) determined from the Tano cone
analysis at 630 GeV
Hard-Scattering Cut-Off PT0
5
PYTHIA 6.206
ε = 0.25 (Set A))
4
PT0 (GeV/c)
¨ Shows the “transverse”
15
3
2
ε = 0.16 (default)
1
Rick Field Fermilab MC Workshop
Reference point
October 4, 2002!
E = 1.8 TeV
100
1,000
10,000
100,000
CM Energy W (GeV)
0
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 8
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
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 9
All use LO αs
with Λ = 192 MeV!
PYTHIA 6.2 Tunes
UE Parameters
ISR 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
PARP(84)
0.4
0.4
0.5
PARP(85)
1.0
1.0
0.33
PARP(86)
1.0
1.0
0.66
PARP(89)
1.96 TeV
1.96 TeV
1.0 TeV
PARP(90)
0.16
0.16
0.16
PARP(62)
1.25
1.25
1.0
PARP(64)
0.2
0.2
1.0
PARP(67)
2.5
2.5
1.0
MSTP(91)
1
1
1
PARP(91)
2.1
2.1
1.0
PARP(93)
15.0
15.0
5.0
ATLAS energy dependence!
Intrinsic KT
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 10
All use LO αs
with Λ = 192 MeV!
PYTHIA 6.2 Tunes
UE Parameters
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
PARP(84)
Tune
AW
Tune A
ISR Parameter
0.4
0.4
Tune
B
PARP(85)
1.0
1.0
0.33
PARP(86)
1.0
1.0
0.66
PARP(89)
1.96 TeV
1.96 TeV
1.0 TeV
PARP(90)
0.16
0.16
0.16
PARP(62)
1.25
1.25
1.0
PARP(64)
0.2
0.2
1.0
PARP(67)
2.5
2.5
1.0
MSTP(91)
1
1
1
PARP(91)
PARP(93)
Tune 2.1
DW
15.0
2.1
15.0
ATLAS energy dependence!
Tune BW
1.0
Tune
D6
5.0
Tune D
Tune D6T
Intrinsic KT
Workshop on Early LHC Physics
May 6, 2009
0.5
Rick Field – Florida/CDF/CMS
Page 11
All use LO αs
with Λ = 192 MeV!
PYTHIA 6.2 Tunes
UE Parameters
Tune A
ISR 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
1.96S320,
TeV
1.0 TeV
Peter Skands
(Tune
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
Workshop on Early LHC Physics
May 6, 2009
1.0
Tune
D6
5.0
Rick Field – Florida/CDF/CMS
Page 12
Peter’s Pythia Tunes WEBsite
¨ http://home.fnal.gov/~skands/leshouches-plots/
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 13
Peter’s Pythia Tunes WEBsite
¨ http://home.fnal.gov/~skands/leshouches-plots/
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 14
1st Workshop on Energy Scaling
in Hadron-Hadron Collisions
Peter Skands!
Renee Fatemi gave a talk on the
“underlying event at ATAR!
“On the Boarder” restaurant, Aurora, IL
April 27, 2009
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 15
The “Underlying Event” at STAR
¨ At STAR they have measured the “underlying event at W = 200 GeV (|η| < 1, pT > 0.2 GeV)
and compared with Pythia Tune A.
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 16
The “Underlying Event” at STAR
¨ At STAR they have measured the “underlying event at W = 200 GeV (|η| < 1, pT > 0.2 GeV)
and compared with Pythia Tune A.
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 17
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| < 5.9
Proton
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
Final-State
Radiation
Outgoing Parton
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 18
Charged Particle Density: dN/dη
Charged Particle Density: dN/dη
Charged Particle Density: dN/dη
5.0
2.0
PY Tune A
generator level
4.0
3.0
2.0
PY64 Tune S320
PY64 Tune P329
1.0
Min-Bias
1.96 TeV
Charged Particles (all PT)
PY64 Tune P329
RDF Preliminary
Charged Particle Density
Charged Particle Density
RDF Preliminary
generator level
1.5
PY Tune A
1.0
PY64 Tune S320
0.5
Min-Bias
1.96 TeV
Charged Particles (PT>0.5 GeV/c)
0.0
0.0
-8
-6
-4
-2
0
2
4
6
8
-8
-6
PseudoRapidity η
-4
-2
0
2
4
6
8
PseudoRapidity η
¨Charged particle (all pT) pseudo-rapidity ¨Charged particle (pT>0.5 GeV/c) pseudodistribution, dNchg/dηdφ, at 1.96 TeV for
inelastic non-diffractive collisions from
PYTHIA Tune A, Tune S320, and Tune
P324.
Workshop on Early LHC Physics
May 6, 2009
rapidity distribution, dNchg/dηdφ, at 1.96
TeV for inelastic non-diffractive collisions
from PYTHIA Tune A, Tune S320, and
Tune P324.
Rick Field – Florida/CDF/CMS
Page 19
Charged Particle Density: dN/dη
RDF LHC Prediction!
Charged Particle Density: dN/dη
Charged Particle Density: dN/dη
8.0
5.0
generator level
4.0
3.0
2.0
PY64 Tune S320
PY64 Tune P329
1.0
PY64 Tune P329
PY Tune A
Charged Particle Density
Charged Particle Density
RDF Preliminary
Min-Bias
1.96 TeV
Charged Particles (all PT)
RDF Preliminary
generator level
6.0
4.0
PY Tune A
PY64 Tune S320
2.0
0.0
0.0
-8
-6
-4
-2
0
2
4
6
8
-8
-6
-4
-2
0
2
4
6
PseudoRapidity η
PseudoRapidity η
“Minumum Bias” Collisions
Proton
Min-Bias
14 TeV
Charged Particles (all PT)
“Minumum Bias” Collisions
AntiProton
Tevatron
Proton
Proton
LHC
¨Charged particle (all pT) pseudo-rapidity distribution, dNchg/dηdφ, at 1.96 TeV for
inelastic non-diffractive collisions from PYTHIA Tune A, Tune S320, and Tune P324.
¨Extrapolations of PYTHIA Tune A, Tune S320, and Tune P329 to the LHC.
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 20
8
Min-Bias Correlations
< pT > [GeV/c]
1.4
Average PT versus Nchg
Average PT (GeV/c)
1.4
CDF Run 2 Preliminary
pyDW
data corrected
generator level theory
“Minumum
Bias” Collisions
pyA
1.2
Proton
1.0
Min-Bias
1.96 TeV
AntiProton
CDF RunII Preliminary
1.3
1.2
1.1
ATLAS
0.8
1
Charged Particles (|η|<1.0, PT>0.4 GeV/c)
0.6
0
10
20
30
40
50
0.9
|η|≤ 1 and pT ≥ 0.4 GeV
Number of Charged Particles
0.8
Data RunII MB+HM
Pythia TuneA, hadron level
0.7
0
5
10
15
20
25
30
35
40
45
50
multiplicity
¨ Data at 1.96 TeV on the average pT of charged particles versus the number of charged particles (pT >
0.4 GeV/c, |η| < 1) for “min-bias” collisions at CDF Run 2. The data are corrected to the particle level
and are compared with PYTHIA Tune A at the particle level (i.e. generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 21
Min-Bias: Average PT versus Nchg
¨ Beam-beam remnants (i.e. soft hard core) produces
Average PT versus Nchg
Average PT (GeV/c)
1.4
CDF Run 2 Preliminary
Min-Bias
1.96 TeV
data corrected
generator level theory
1.2
low multiplicity and small <pT> with <pT>
independent of the multiplicity.
¨ Hard scattering (with no MPI) produces large
pyA
multiplicity and large <pT>.
pyAnoMPI
1.0
¨ Hard scattering (with MPI) produces large
0.8
multiplicity and medium <pT>.
ATLAS
Charged Particles (|η|<1.0, PT>0.4 GeV/c)
0.6
0
5
10
15
20
25
30
35
40
This observable is sensitive
to the MPI tuning!
Number of Charged Particles
“Hard” Hard Core (hard scattering)
Outgoing Parton
“Soft” Hard Core (no hard scattering)
PT(hard)
CDF “Min-Bias”
=
Proton
+
AntiProton
Proton
AntiProton
Underlying Event
Underlying Event
Initial-State
Radiation
Final-State
Radiation
Multiple-Parton Interactions
+
Proton
AntiProton
Underlying Event
Outgoing Parton
Workshop on Early LHC Physics
May 6, 2009
Outgoing Parton
PT(hard)
Initial-State
Radiation
The CDF “min-bias” trigger
picks up most of the “hard
core” component!
Outgoing Parton
Underlying Event
Final-State
Radiation
Rick Field – Florida/CDF/CMS
Page 22
Average PT versus Nchg
Average PT
PT versus
versus Nchg
Nchg
Average
Average PT versus Nchg
2.5
2.5
CDF Run 2 Preliminary
data corrected
generator level theory
1.2
CDFRun
Run22Preliminary
Preliminary
CDF
Min-Bias
1.96 TeV
Average
Average PT
PT (GeV/c)
(GeV/c)
Average PT (GeV/c)
1.4
pyA
pyAnoMPI
1.0
0.8
ATLAS
data corrected
generator
level theory
generator level theory
2.0
2.0
HW
HW
pyAW
pyAW
"Drell-YanProduction"
Production"
"Drell-Yan
70<<M(pair)
M(pair)<<110
110GeV
GeV
70
1.5
1.5
JIM
JIM
1.0
1.0
ATLAS
ATLAS
Charged Particles (|η|<1.0, PT>0.4 GeV/c)
0.6
ChargedParticles
Particles(|η|<1.0,
(|η|<1.0,PT>0.5
PT>0.5GeV/c)
GeV/c)
Charged
excludingthe
thelepton-pair
lepton-pair
excluding
0.5
0.5
0
5
10
15
20
25
30
35
40
00
55
10
10
Number of Charged Particles
15
15
20
20
25
25
30
30
Numberof
ofCharged
ChargedParticles
Particles
Number
Drell-Yan Production
Lepton
“Minumum Bias” Collisions
Proton
AntiProton
Proton
AntiProton
Underlying Event
Underlying Event
Anti-Lepton
¨ Data at 1.96 TeV on the average pT of charged particles versus the number of charged particles (pT > 0.4 GeV/c, |η| <
1) for “min-bias” collisions at CDF Run 2. The data are corrected to the particle leveland are compared with
PYTHIA Tune A, Tune DW, and the ATLAS tune at the particle level (i.e. generator level).
¨ Particle level predictions for the average pT of charged particles versus the number of charged particles (pT > 0.5
GeV/c, |η| < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV) at CDF Run 2.
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 23
35
35
Average PT versus Nchg
¨ Z-boson production (with low pT(Z) and no MPI)
No MPI!
Average PT versus Nchg
produces low multiplicity and small <pT>.
2.5
Average PT (GeV/c)
CDF Run 2 Preliminary
data corrected
generator level theory
2.0
HW
¨ High pT Z-boson production produces large
pyAW
multiplicity and high <pT>.
"Drell-Yan Production"
70 < M(pair) < 110 GeV
¨ Z-boson production (with MPI) produces large
1.5
multiplicity and medium <pT>.
JIM
1.0
ATLAS
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
0.5
0
5
10
15
20
25
30
35
Number of Charged Particles
Drell-Yan Production (no MPI)
High PT Z-Boson Production
Lepton
Initial-State Radiation
Outgoing Parton
Final-State Radiation
Drell-Yan
=
Proton
AntiProton
Underlying Event
Underlying Event
Anti-Lepton
+
+
Drell-Yan Production (with MPI)
Proton
Proton
Lepton
AntiProton
Z-boson
AntiProton
Underlying Event
Underlying Event
Anti-Lepton
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 24
Average PT(Z) versus Nchg
No MPI!
Average PT versus Nchg
PT(Z-Boson)
PT(Z-Boson) versus
versus Nchg
Nchg
80
80
2.5
data corrected
generator level theory
2.0
CDF
CDF Run
Run 22 Preliminary
Preliminary
HW
Average PT(Z) (GeV/c)
Average PT (GeV/c)
CDF Run 2 Preliminary
pyAW
"Drell-Yan Production"
70 < M(pair) < 110 GeV
1.5
JIM
1.0
ATLAS
generator
level theory
data corrected
generator level theory
60
60
pyAW
pyAW
HW
HW
"Drell-Yan
"Drell-Yan Production"
Production"
70
70 << M(pair)
M(pair) << 110
110 GeV
GeV
40
40
JIM
JIM
20
20
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
ATLAS
ATLAS
Charged
Charged Particles
Particles (|η|<1.0,
(|η|<1.0, PT>0.5
PT>0.5 GeV/c)
GeV/c)
excluding
excluding the
the lepton-pair
lepton-pair
00
0.5
0
5
10
15
20
25
30
35
00
55
Outgoing Parton
Lepton
Initial-State Radiation
Proton
Proton
AntiProton
AntiProton
Underlying Event
Underlying Event
15
15
20
20
25
25
30
30
35
35
40
40
Number
Number of
of Charged
Charged Particles
Particles
Number of Charged Particles
High PDrell-Yan
Production
T Z-BosonProduction
10
10
¨ Predictions for the average PT(Z-Boson) versus
the number of charged particles (pT > 0.5
GeV/c, |η| < 1, excluding the lepton-pair) for for
Drell-Yan production (70 < M(pair) < 110 GeV)
at CDF Run 2.
Anti-Lepton
Z-boson
¨ Data on the average pT of charged particles versus the number of charged particles (pT > 0.5 GeV/c, |η| < 1,
excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV) at CDF Run 2. The data are
corrected to the particle level and are compared with various Monte-Carlo tunes at the particle level (i.e.
generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 25
Average PT versus Nchg
PT(Z) < 10 GeV/c
Average
Charged
PT
versus
Nchg
Average
Average Charged
Charged PT
PT versus
versus Nchg
Nchg
Average
PT
(GeV/c)
AveragePT
PT(GeV/c)
(GeV/c)
Average
1.4
1.4
1.4
CDF
Run
Preliminary
CDF
CDF Run
Run 22
2 Preliminary
Preliminary
data corrected
generator
level
generator
level theory
theory
generator level theory
1.2
1.2
1.2
pyAW
pyAW
pyAW
JIM
JIM
No MPI!
1.0
1.0
1.0
HW
HW
HW
0.8
0.8
0.8
"Drell-Yan
Production"
"Drell-Yan
"Drell-Yan Production"
Production"
70
<
M(pair)
110
GeV
70
<
M(pair)
70 < M(pair) <<
< 110
110 GeV
GeV
PT(Z)
10
GeV/c
PT(Z)
PT(Z) <<
< 10
10 GeV/c
GeV/c
ATLAS
ATLAS
Charged
Particles
(|η|<1.0,
PT>0.5
GeV/c)
Charged
Charged Particles
Particles (|η|<1.0,
(|η|<1.0, PT>0.5
PT>0.5 GeV/c)
GeV/c)
excluding
the
lepton-pair
excluding
excluding the
the lepton-pair
lepton-pair
0.6
0.6
0.6
00
0
55
5
10
10
10
15
15
15
20
20
20
25
25
25
30
30
30
35
35
35
Number
of
Charged
Particles
Number
Number of
of Charged
Charged Particles
Particles
Drell-Yan Production
Proton
Lepton
AntiProton
Underlying Event
Underlying Event
Anti-Lepton
¨ Predictions
for thepTaverage
pT ofparticles
chargedversus
particles
theofnumber
charged(p
particles
(pT > 0.5
Data the average
of charged
theversus
number
chargedofparticles
|η| GeV/c,
< 1, |η|
T > 0.5 GeV/c,
10 GeV/c)
<
1, excluding
the lepton-pair)
forDrell-Yan
for Drell-Yan
production
< M(pair)
< GeV,
110 GeV,
PT(pair)
< 10<GeV/c)
at at
excluding
the lepton-pair)
for for
production
(70 <(70
M(pair)
< 110
PT(pair)
CDF Run 2. The data are corrected to the particle level and are compared with various Monte-Carlo tunes at
the particle level (i.e. generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 26
Average PT versus Nchg
PT(Z) < 10 GeV/c
Average
Charged
PT
versus
Nchg
Average
Average Charged
Charged PT
PT versus
versus Nchg
Nchg
CDF
Run
Preliminary
CDF
CDF Run
Run 22
2 Preliminary
Preliminary
data corrected
generator
level
generator
level theory
theory
generator level theory
1.2
1.2
1.2
pyAW
pyAW
pyAW
1.0
1.0
1.0
HW
HW
HW
0.8
0.8
0.8
"Drell-Yan
Production"
"Drell-Yan
"Drell-Yan Production"
Production"
70
<
M(pair)
110
GeV
70
<
M(pair)
70 < M(pair) <<
< 110
110 GeV
GeV
PT(Z)
10
GeV/c
PT(Z)
PT(Z) <<
< 10
10 GeV/c
GeV/c
CDF Run 2 Preliminary
JIM
JIM
Average PT (GeV/c)
Average
PT
(GeV/c)
AveragePT
PT(GeV/c)
(GeV/c)
Average
1.4
1.4
1.4
Average PT versus Nchg
1.4
ATLAS
ATLAS
Drell-Yan PT > 0.5 GeV PT(Z) < 10 GeV/c
data corrected
generator level theory
1.2
pyAW
No MPI!
1.0
Min-Bias PT > 0.4 GeV/c
0.8
Charged
Particles
(|η|<1.0,
PT>0.5
GeV/c)
Charged
Charged Particles
Particles (|η|<1.0,
(|η|<1.0, PT>0.5
PT>0.5 GeV/c)
GeV/c)
excluding
the
lepton-pair
excluding
excluding the
the lepton-pair
lepton-pair
Charged Particles (|η|<1.0)
pyA
0.6
0.6
0.6
0.6
00
0
55
5
10
10
10
15
15
15
20
20
20
25
25
25
30
30
30
35
35
35
0
Number
of
Charged
Particles
Number
Number of
of Charged
Charged Particles
Particles
Drell-Yan Production
Proton
20
30
40
Number of Charged Particles
Lepton
AntiProton
Underlying Event
10
Underlying Event
Remarkably similar behavior!
Perhaps indicating that MPIProton
playing an important role in
both processes.
“Minumum Bias” Collisions
AntiProton
Anti-Lepton
¨ Predictions
for thepTaverage
pT ofparticles
chargedversus
particles
theofnumber
charged(p
particles
(pT > 0.5
Data the average
of charged
theversus
number
chargedofparticles
|η| GeV/c,
< 1, |η|
T > 0.5 GeV/c,
10 GeV/c)
<
1, excluding
the lepton-pair)
forDrell-Yan
for Drell-Yan
production
< M(pair)
< GeV,
110 GeV,
PT(pair)
< 10<GeV/c)
at at
excluding
the lepton-pair)
for for
production
(70 <(70
M(pair)
< 110
PT(pair)
CDF Run 2. The data are corrected to the particle level and are compared with various Monte-Carlo tunes at
the particle level (i.e. generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 27
Min-Bias: Average PT versus Nchg
RDF LHC Prediction!
Average PT versus Nchg
Average PT versus Nchg
1.4
1.6
RDF Preliminary
generator level
PY Tune A
1.2
Average PT (GeV/c)
Average PT (GeV/c)
RDF Preliminary
PY64 Tune P329
PY Tune DW
1.0
PY64 Tune S320
0.8
PY64 Tune N324
Min-Bias
1.96 TeV
1.4
PY Tune A
1.2
PY64 Tune P329
1.0
PY64 Tune S320
0.8
Min-Bias
14 TeV
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.6
PY Tune DW
generator level
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.6
0
5
10
15
20
25
30
35
0
5
Number of Charged Particles
10
15
“Minumum Bias” Collisions
Proton
20
25
30
35
40
Number of Charged Particles
“Minumum Bias” Collisions
Proton
AntiProton
Tevatron
Proton
LHC
¨The average pT of charged particles versus the number of charged particles (pT > 0.5
GeV/c, |η| < 1) for “min-bias” collisions at 1.96 TeV from PYTHIA Tune A, Tune DW,
Tune S320, Tune N324, and Tune P324.
¨Extrapolations of PYTHIA Tune A, Tune DW, Tune S320, and Tune P324 to the
LHC.
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 28
CDF Run 2 Min-Bias “Associated”
Charged Particle Density
“Associated” densities do
not include PTmax!
Highest pT
charged particle!
Charged Particle Density: dN/dηdφ
0.5
PTmax Direction
Δφ
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|<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
Δφ (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
chg/dηdφ,
in “min-bias” collisions (pT > 0.5 GeV/c, |η| <
at the the “associated”
density, dN
accompanying
PTmax
than
it
is
to
1).
find a particle in the central region!
¨ Shows the data
on the Δφ dependence of the “associated” charged particle density,
dNchg/dηdφ, for charged particles (pT > 0.5 GeV/c, |η| < 1, not including PTmax) relative
to PTmax (rotated to 180o) for “min-bias” events. Also shown is the average charged
particle density, dNchg/dηdφ, for “min-bias” events.
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 29
CDF Run 2 Min-Bias “Associated”
Charged Particle Density Rapid rise in the particle
density in the “transverse”
region as PTmax increases!
Associated Particle Density: dN/dηdφ
PTmaxDirection
Direction
PTmax
Δφ
“Toward”
“Transverse”
“Transverse”
Correlations in φ
“Away”
Associated Particle Density
Jet #1
Δφ
PTmax > 2.0 GeV/c
1.0
PTmax > 2.0 GeV/c
PTmax > 1.0 GeV/c
PTmax > 0.5 GeV/c
Transverse
Region
0.8
0.6
Charged Particles
(|η|<1.0, PT>0.5 GeV/c)
CDF Preliminary
data uncorrected
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
Δφ (degrees)
Ave Min-Bias
0.25 per unit η-φ
PTmax > 0.5 GeV/c
¨ Shows the data on the Δφ dependence of the “associated” charged particle density,
dNchg/dηdφ, for charged particles (pT > 0.5 GeV/c, |η| < 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!).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 30
CDF Run 2 Min-Bias “Associated”
Charged Particle Density
PY Tune A
PTmax > 2.0 GeV/c
Δφ
“Toward”
“Transverse”
“Transverse”
Correlations in φ
“Away”
Associated Particle Density
PTmax Direction
Direction
PTmax
Δφ
Associated Particle Density: dN/dηdφ
1.0
PTmax > 2.0 GeV/c
PY Tune A
PTmax > 0.5 GeV/c
PY Tune A
Transverse
Region
0.8
0.6
CDF Preliminary
data uncorrected
theory + CDFSIM
PY Tune A 1.96 TeV
Transverse
Region
0.4
0.2
PTmax
PTmax not included
(|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
Δφ (degrees)
¨ Shows the data on the Δφ dependence of the “associated” charged particle density,
dNchg/dηdφ, for charged particles (pT > 0.5 GeV/c, |η| < 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”).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 31
Min-Bias “Associated”
Charged Particle Density
PTmax Direction
Associated Charged Particle Density: dN/dηdφ
Δφ
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
PTmax > 0.5 GeV/c
PTmax > 1.0 GeV/c
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
0
30
60
90
120
150
180
210
240
270
300
330
360
Δφ (degrees)
¨ Shows the Δφ dependence of the “associated” charged particle density, dNchg/dηdφ, for charged
particles (pT > 0.5 GeV/c, |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).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 32
Min-Bias “Associated”
Charged Particle Density
PTmax Direction
Associated Charged Particle Density: dN/dηdφ
Δφ
Associated Charged Particle Density: dN/dηdφ
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|<1.0, PT>0.5 GeV/c)
Charged Particles (|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
Δφ (degrees)
4
6
8
10
12
14
16
18
PTmax (GeV/c)
¨ Shows the Δφ dependence of the “associated” charged particle density, dNchg/dηdφ, for charged
particles (pT > 0.5 GeV/c, |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
Δφ
“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| < 1, not including PTmax) for “min-bias” events at 1.96 TeV from
PYTHIA Tune A (generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 33
20
Min-Bias “Associated”
Charged Particle Density
PTmax Direction
Associated Charged
Charged Particle
Particle Density:
Density: dN/d
dN/dηdφ
ηdφ
Associated
Δφ
Associated Charged Particle Density: dN/dηdφ
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"
1.0
"Transverse"
“Away”
0.4
0.5
Charged
ChargedParticles
Particles(|η|<1.0,
(|η|<1.0,PT>0.5
PT>0.5 GeV/c)
GeV/c)
Charged Particles (|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
Δφ (degrees)
54
6
10
8
10
15
12
14
20
16
18
PTmax
PTmax (GeV/c)
(GeV/c)
¨ Shows the Δφ dependence of the “associated” charged particle density, dNchg/dηdφ, for charged
particles (pT > 0.5 GeV/c, |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
Δφ
“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| < 1, not including PTmax) for “min-bias” events at 1.96 TeV from
PYTHIA Tune A (generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 34
25
20
Min-Bias “Associated”
Charged Particle Density
PTmax Direction
Associated Charged
Charged
Particle
Density:
dN/dηdφ
Associated
"Transverse"
ChargedParticle
ParticleDensity:
Density:dN/d
dN/dηηddφφ
Δφ
Associated Charged Particle Density: dN/dηdφ
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|<1.0, PT>0.5 GeV/c)
0.0
"Transverse"
Charged
Density
Charged Particle
Density
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(|η|<1.0,
(|η|<1.0,PT>0.5
PT>0.5 GeV/c)
GeV/c)
Charged Particles (|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
Δφ (degrees)
54
6
8
10
10
12
15
14
16
20
18
PTmax (GeV/c)
(GeV/c)
PTmax
¨ Shows the Δφ dependence of the “associated” charged particle density, dNchg/dηdφ, for charged
particles (pT > 0.5 GeV/c, |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
Δφ
“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| < 1, not including PTmax) for “min-bias” events at 1.96 TeV from
PYTHIA Tune A (generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 35
25
20
25
Min-Bias “Associated”
Charged Particle Density
Associated Charged Particle Density: dN/dηdφ
ηdφ
Associated
Associated Charged
Charged Particle
Particle Density:
Density: dN/d
dN/dηdφ
0.60
PY64 Tune P329
PY64 Tune N324
RDF
Preliminary
RDF
Preliminary
generator
level
generator
level
0.15
0.40
0.10
PY64 Tune S320
0.20
0.05
PY64
Tune
PY
Tune
A S320
Min-Bias
Min-Bias
1.96
1.96 TeV
TeV
PTmax
> 0.5
GeV/c
PTmax
> 2.0
GeV/c
Charged
Particles
(PT>0.5
GeV/c)
Charged
Particles
(PT>0.5
GeV/c)
Associated Charged Density
Associated Charged
Charged Density
Density
Associated
0.20
0.60
RDF Preliminary
PY Tune A
generator level
PY64 Tune P329
0.40
0.20
PY64 Tune S320
Min-Bias
1.96 TeV
PTmax > 2.0 GeV/c
Charged Particles (PT>0.5 GeV/c)
0.00
0.00
0.00
00
30
30
60
60
90
90
120
120 150
150 180
180 210
210 240
240 270
270 300
300 330
330 360
360
0
30
60
90
120
150
180
210
240
270
300
330
360
Δφ (degrees)
Δφ
Δφ (degrees)
(degrees)
¨ Shows the Δφ dependence of the “associated” charged particle density, dNchg/dηdφ, for charged
particles (pT > 0.5 GeV/c, |η| < 1, not including PTmax) relative to PTmax (rotated to 180o) for
“min-bias” events at 1.96 TeV with PTmax > 0.5 GeV/c for PYTHIA Tune A, Tune S320, Tune
P320 (generator level).
¨ Shows the Δφ dependence of the “associated” charged particle density, dNchg/dηdφ, for charged
particles (pT > 0.5 GeV/c, |η| < 1, not including PTmax) relative to PTmax (rotated to 180o) for
“min-bias” events at 1.96 TeV with PTmax > 2.0 GeV/c for PYTHIA Tune A, Tune S320, Tune
P320 (generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 36
Min-Bias “Associated”
Charged Particle Density
Associated Charged Particle Density: dN/dηdφ
Associated Charged Particle Density: dN/dηdφ
1.6
1.6
py Tune A generator level
Charged Particle Density
Charged Particle Density
RDF Preliminary
Min-Bias
1.96 TeV
RDF Preliminary
1.2
"Toward"
"Away"
0.8
"Transverse"
0.4
Min-Bias
1.96 TeV
py64 Tune S320 generator level
1.2
"Toward"
0.8
"Away"
"Transverse"
0.4
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
Charged Particles (|η|<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
10
14
16
18
20
PTmax (GeV/c)
PTmax (GeV/c)
PTmax Direction
PTmax Direction
Δφ
Δφ
“Toward”
“Toward”
“Transverse”
12
“Transverse”
“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, |η| < 1, not including PTmax) for
“min-bias” events at 1.96 TeV from PYTHIA Tune A and Tune S320 at the particle level (i.e.
generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 37
Min-Bias “Associated”
Charged Particle Density
"Toward"
Associated
ChargedDensity:
Density:dN/dηdφ
dN/dηdφ
Associated
Charged Particle
Associated Charged Particle Density: dN/dηdφ
1.6
1.6
1.6
Charged Particle Density
Charged Particle
Density
Associated
Charged
Density
Min-Bias
1.96 TeV
RDF Preliminary
py Tune A generator level
1.2
"Toward"
"Away"
0.8
"Transverse"
0.4
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
RDF
Preliminary
RDF
Preliminary
Min-Bias
PY Tune
A
py64 generator
Tune S320level
generator level
1.96 TeV
1.2
1.2
"Toward"
0.8
0.8
"Away"
"Transverse"
Min-Bias
PY64 Tune P329
1.96 TeV
0.4
0.4
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
PY64 Tune S320
0.0
0.0
0.0
0
2
4
6
8
10
12
14
16
18
20
00
22
44
66
88
10
10
14
14
16
16
18
18
20
20
PTmax (GeV/c)
(GeV/c)
PTmax
PTmax (GeV/c)
PTmax Direction
PTmax Direction
Δφ
Δφ
“Toward”
“Toward”
“Transverse”
12
12
“Transverse”
“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, |η| < 1, not including PTmax) for
“min-bias” events at 1.96 TeV from PYTHIA Tune A and Tune S320 at the particle level (i.e.
generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 38
Min-Bias “Associated”
Charged Particle Density
RDF LHC Prediction!
"Transverse" Charged Particle Density: dN/dηdφ
"Transverse" Charged Particle Density: dN/dηdφ
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
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
PY Tune DWT
RDF Preliminary
generator level
1.2
0.8
PY64 Tune P329
PY Tune A
0.4
PY Tune DW
PY64 Tune S320
Min-Bias
14 TeV
Charged Particles (|η|<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
15
PTmax Direction
PTmax Direction
Δφ
Δφ
“Toward”
“Toward”
“Transverse”
25
PTmax (GeV/c)
PTmax (GeV/c)
“Transverse”
20
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, |η| < 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, and Tune P329 to the LHC.
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 39
Charged Particle Density
Charged Particle Density: dN/dηdφ
Charged Particle Density: dN/dηdφ
4
CDF Run 2 Preliminary
CDF Run 2 Preliminary
data corrected
pyAW generator level
2
"Away"
"Drell-Yan Production"
70 < M(pair) < 110 GeV
1
"Transverse"
"Toward"
0
0
20
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
40
60
80
100
Average Charged Density
Average Charged Density
3
data corrected
pyA generator level
3
"Toward"
2
"Leading Jet"
MidPoint R=0.7 |η(jet#1)|<2
1
"Transverse"
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0
0
20
40
Δφ
High PT Z-Boson Production
60
80
100
120
140
Jet #1 Direction
Outgoing Parton
“Transverse”
200
PT(hard)
“Toward”
AntiProton
“Transverse”
“Transverse”
180
Outgoing Parton
Δφ
Initial-State Radiation
“Toward”
Proton
160
PT(jet#1) (GeV/c)
PT(Z-Boson) (GeV/c)
Z-Boson Direction
"Away"
“Transverse”
Initial-State Radiation
Proton
AntiProton
Underlying Event
Underlying Event
“Away”
“Away”
Outgoing Parton
Z-boson
Final-State
Radiation
¨ Data at 1.96 TeV on the density of charged particles, dN/dηdφ, with pT > 0.5 GeV/c and |η| < 1 for “Z-Boson”
and “Leading Jet” events as a function of the leading jet pT or PT(Z) for the “toward”, “away”, and
“transverse” regions. The data are corrected to the particle level (with errors that include both the statistical
error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the
particle level (i.e. generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 40
Charged Particle Density
Charged
ParticleParticle
Density:Density:
dN/dηdφdN/dηdφ
"Transverse"
Charged
"Away"
Charged
Particle
Density:
dN/dηdφ
Charged
Particle
Density:
dN/dηdφ
44
CDFRun
Run22Preliminary
Preliminary
CDF
CDF
CDFRun
Run22Preliminary
Preliminary
data corrected
data corrected
generator level theory
pyAW generator level
0.9
2
"Leading
Jet"
"Away"
"Drell-Yan Production"
70 < M(pair) < 110 GeV
0.6
1
"Transverse"
"Z-Boson"
0.3
"Toward"
0
0.0
00
20
20
40
60
40
80
Charged Particles
Particles (|η|<1.0,
PT>0.5 GeV/c)
GeV/c)
Charged
(|η|<1.0, PT>0.5
excluding the lepton-pair
100
60
120
80
160
140
180
100
200
Average
Density
"Away" Charged
Charged Density
"Transverse"
ChargedDensity
Density
Average Charged
3
1.2
33
Δφ
High PT Z-Boson Production
"Away"
"Toward"
22
"Leading Jet"
MidPoint R=0.7 |η(jet#1)|<2
11
"Z-Boson""Transverse"
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
00
00
20
20
40
40
60
60
80
80
100
100
120
120
140
140
Jet #1 Direction
Outgoing Parton
“Transverse”
200
200
PT(hard)
“Toward”
AntiProton
“Transverse”
“Transverse”
180
180
Outgoing Parton
Δφ
Initial-State Radiation
“Toward”
Proton
160
160
PT(jet#1)
or PT(Z-Boson)
PT(jet#1)
(GeV/c) (GeV/c)
PT(Z-Boson)
(GeV/c)(GeV/c)
PT(jet#1)
or PT(Z-Boson)
Z-Boson Direction
"Leading Jet"
data
datacorrected
corrected
pyA generator
generator
levellevel
theory
“Transverse”
Initial-State Radiation
Proton
AntiProton
Underlying Event
Underlying Event
“Away”
“Away”
Outgoing Parton
Z-boson
Final-State
Radiation
¨ Data at 1.96 TeV on the density of charged particles, dN/dηdφ, with pT > 0.5 GeV/c and |η| < 1 for “Z-Boson”
and “Leading Jet” events as a function of the leading jet pT or PT(Z) for the “toward”, “away”, and
“transverse” regions. The data are corrected to the particle level (with errors that include both the statistical
error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the
particle level (i.e. generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 41
Charged Particle Density
HERWIG + JIMMY
Tune
(PTJIM
= 3.6)
Charged
ParticleParticle
Density:Density:
dN/dηdφ
"Transverse"
Charged
dN/dηdφCharged Particle Density:"Away"
Charged
Particle
Density:
dN/dηdφ
"Away"
dN/dηdφ
Charged
Particle
Density:
dN/dηdφ
3
CDF Run 2 Preliminary
data corrected
data corrected
generator level theory
pyAW generator level
0.9
2
"Drell-Yan Production"
70 < M(pair) < 110 GeV
0.6
1
"Toward"
0
0.0
00
20
20
40
60
"Leading
Jet"
"Away" data corrected
generator level theory
2
"Drell-Yan Production"
70 < M(pair) < 110 GeV
40
80
Charged Particles
Particles (|η|<1.0,
PT>0.5
GeV/c)
HW
Charged
(|η|<1.0, PT>0.5
GeV/c)
excluding the lepton-pair
100
0
60
120
0
80
160
20
140
180
PT(Z-Boson)
(GeV/c)(GeV/c)
PT(jet#1)
or PT(Z-Boson)
Z-Boson Direction
Δφ
High PT Z-Boson Production
CDF
CDFRun
Run22Preliminary
Preliminary
100
200
40
"Leading Jet"
data
datacorrected
corrected
pyA generator
generator
levellevel
theory
pyAW
1
"Transverse"
"Z-Boson"
0.3
44
Average
Density
"Away" Charged
Charged Density
CDFRun
Run22Preliminary
Preliminary
CDF
"Away" Charged Density
"Transverse"
ChargedDensity
Density
Average Charged
3
1.2
33
"Away"
"Toward"
22
JIM
11
"Leading Jet"
MidPoint R=0.7 |η(jet#1)|<2
"Z-Boson""Transverse"
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
00
00
60
20
20
40
40
60
60
80
80
80
100
100
100
120
120
140
140
Jet #1 Direction
“Transverse”
PT(hard)
“Toward”
AntiProton
“Transverse”
“Transverse”
200
200
Outgoing Parton
Δφ
Initial-State Radiation
“Toward”
Proton
180
180
PT(jet#1)
or PT(Z-Boson)
PT(jet#1)
(GeV/c) (GeV/c)
PT(Z-Boson) (GeV/c)
Outgoing Parton
160
160
“Transverse”
Initial-State Radiation
Proton
AntiProton
Underlying Event
Underlying Event
“Away”
“Away”
Outgoing Parton
Z-boson
Final-State
Radiation
¨ Data at 1.96 TeV on the density of charged particles, dN/dηdφ, with pT > 0.5 GeV/c and |η| < 1 for “Z-Boson”
and “Leading Jet” events as a function of the leading jet pT or PT(Z) for the “toward”, “away”, and
“transverse” regions. The data are corrected to the particle level (with errors that include both the statistical
error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the
particle level (i.e. generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 42
Charged Particle <pT>
"Toward" Average PT Charged
"Transverse" Average PT
1.6
CDF Run 2 Preliminary
CDF Run 2 Preliminary
data corrected
generator level theory
"Toward" <PT> (GeV/c)
"Transverse" Average PT (GeV/c)
2.0
PY Tune A
1.5
1.0
"Leading Jet"
MidPoint R=0.7 |η(jet#1)|<2
HW
data corrected
generator level theory
"Drell-Yan Production"
70 < M(pair) < 110 GeV
pyDW
pyAW
1.2
0.8
ATLAS
JIM
HW
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.4
0.5
0
50
100
150
200
250
300
350
400
0
20
40
60
PT(jet#1) (GeV/c)
Jet #1 Direction
100
Z-BosonDirection
Δφ
Δφ
“Toward”
“Transverse”
80
PT(Z-Boson) (GeV/c)
“Toward”
“Transverse”
“Transverse”
“Away”
“Transverse”
“Away”
¨ Data at 1.96 TeV on the charged particle average pT, with pT > 0.5 GeV/c and |η| < 1 for the “toward”
region for “Z-Boson” and the “transverse” region for “Leading Jet” events as a function of the
leading jet pT or PT(Z). The data are corrected to the particle level (with errors that include both the
statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune
A, respectively, at the particle level (i.e. generator level). The Z-Boson data are also compared with
PYTHIA Tune DW, the ATLAS tune, and HERWIG (without MPI)
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 43
Z-Boson: “Towards”, Transverse”,
& “TransMIN” Charge Density
Charged Particle Density: dN/dηdφ
Charged
Particle
Density: dN/dηdφ
High
PT Z-Boson
Production
Outgoing Parton
0.9
0.9
CDF Run 2 Preliminary
data corrected
pyAW generator level
"Transverse
Charged Density
Charged Density
Initial-State Radiation
Initial-State Radiation
"Drell-Yan Production"
70 < M(pair) < 110 GeV
CDF Run 2 Preliminary
0.6
"Toward"
0.3
"Drell-Yan Production"
70 < M(pair) < 110 GeV
data corrected
Proton
pyAW
generator level
0.6
"Toward"
0.3
Z-boson
Z-boson
"transMIN"
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
0.0
AntiProton
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
0.0
0
20
40
60
80
100
0
PT(Z-Boson) (GeV/c)
20
40
60
100
PT(Z-Boson) (GeV/c)
Z-BosonDirection
Z-Boson Direction
Δφ
Δφ
“Toward”
“Toward”
“Transverse”
80
“TransMAX”
“Transverse”
“TransMIN”
“Away”
“Away”
¨ Data at 1.96 TeV on the density of charged particles, dN/dηdφ, with pT > 0.5 GeV/c and |η| < 1 for “ZBoson” events as a function of PT(Z) for the “toward” and “transverse” regions. The data are
corrected to the particle level (with errors that include both the statistical error and the systematic
uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle
level (i.e. generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 44
Z-Boson: “Towards”, Transverse”,
& “TransMIN” Charge Density
Charged
Particle
Density:
dN/dηdφ
"Toward"
Charged
Particle
Density:
dN/dηdφ
CDF Run 2 Preliminary
CDF Run
2 Preliminary
data corrected
datagenerator
correctedlevel
pyAW
generator level theory
Charged
Particle
Density:
dN/dηdφ
"TransMIN"
Charged
Particle
Density:
dN/dηdφ
High
PT Z-Boson
Production
Outgoing Parton
0.9
0.6
"Transverse
ATLAS
JIM
pyDW
0.6
0.6
"Toward"
0.3
0.3
pyAW
"Drell-Yan Production"
Production"
"Drell-Yan
70 << M(pair)
M(pair) <
70
< 110
110 GeV
GeV
HW
Charged
Charged Particles
Particles (|η|<1.0,
(|η|<1.0, PT>0.5
PT>0.5 GeV/c)
GeV/c)
excluding
excluding the
the lepton-pair
lepton-pair
0.0
0.0
Charged
Density
"TransMIN"
Charged
Density
Charged
Density
"Toward"
Charged
Density
0.9
0.9
Initial-State Radiation
Initial-State Radiation
CDF Run 2 Preliminary
data corrected
Proton
generator
level theory
pyAW
generator
level
"Drell-Yan Production"
"Drell-Yan Production"
70 < M(pair) < 110 GeV
70 < M(pair) < 110 GeV
AntiProtonpyDW
ATLAS
JIM
"Toward"
0.6
0.4
0.3
0.2
Z-boson
Z-boson
"transMIN"
pyAW
HW
Charged
Charged Particles
Particles (|η|<1.0,
(|η|<1.0, PT>0.5
PT>0.5 GeV/c)
GeV/c)
excluding
excluding the
the lepton-pair
lepton-pair
0.0
00
20
20
40
40
60
60
80
80
100
100
0
PT(Z-Boson)
PT(Z-Boson) (GeV/c)
(GeV/c)
20
40
60
100
PT(Z-Boson) (GeV/c)
Z-BosonDirection
Z-Boson Direction
Δφ
Δφ
“Toward”
“Toward”
“Transverse”
80
“TransMAX”
“Transverse”
“TransMIN”
“Away”
“Away”
¨ Data at 1.96 TeV on the density of charged particles, dN/dηdφ, with pT > 0.5 GeV/c and |η| < 1 for “ZBoson” events as a function of PT(Z) for the “toward” and “transverse” regions. The data are
corrected to the particle level (with errors that include both the statistical error and the systematic
uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle
level (i.e. generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 45
Z-Boson: “Towards”, Transverse”,
& “TransMIN” Charge Density
Charged
Particle
Density:
dN/dηdφ
Charged
Particle
Density:
dN/dηdφ
"TransMIN"
Charged
Particle
Density:
dN/dηdφ
"Toward"
Charged
Particle
Density:
dN/dηdφ
"TransMIN" Charged Particle Density:
dN/dηdφ
High
PT Z-Boson
Production
Outgoing Parton
datagenerator
correctedlevel
pyAW
generator level theory
"Toward"
0.3
0.3
HW
20
20
0.6
pyDW
data corrected
generator level theory
0.4
0.2
pyAW
Charged
Charged Particles
Particles (|η|<1.0,
(|η|<1.0, PT>0.5
PT>0.5 GeV/c)
GeV/c)
"Z-Boson"
excluding
excluding the
the lepton-pair
lepton-pair
0.0
0.0
00
CDF Run 2 Preliminary
"Transverse
ATLAS
JIM
0.6
0.6
"Drell-Yan Production"
Production"
"Drell-Yan
70 << M(pair)
M(pair) <
70
< 110
110 GeV
GeV
0.9
0.6
0.8
0.0
60
60 0
40
40
PT(Z-Boson)
PT(Z-Boson) (GeV/c)
(GeV/c)
Charged
Density
"TransMIN"
Charged
Density
CDF Run 2 Preliminary
CDF Run
2 Preliminary
data corrected
"TransMIN" Charged Density
Charged
Density
"Toward"
Charged
Density
0.9
0.9
Initial-State Radiation
Initial-State Radiation
CDF Run 2 Preliminary
data corrected
Proton
generator
level theory
pyAW
generator
level
0.6
0.4
"Leading Jet"
"Drell-Yan Production"
"Drell-Yan Production"
70 < M(pair) < 110 GeV
70 < M(pair) < 110 GeV
AntiProtonpyDW
ATLAS
JIM
"Toward"
0.3
0.2
Z-boson
Z-boson
"transMIN"
Charged
Charged Particles
Particles (|η|<1.0,
(|η|<1.0, PT>0.5
PT>0.5 GeV/c)
GeV/c)
pyAW
HW
excluding
excluding the
the lepton-pair
lepton-pair
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
80 40
20 80
100 80
60100
1000
120
20
140
PT(jet#1) or PT(Z-Boson) (GeV/c)
160
40
180
60
200
100
PT(Z-Boson) (GeV/c)
Z-BosonDirection
Z-Boson Direction
Δφ
Δφ
“Toward”
“Toward”
“Transverse”
80
“TransMAX”
“Transverse”
“TransMIN”
“Away”
“Away”
¨ Data at 1.96 TeV on the density of charged particles, dN/dηdφ, with pT > 0.5 GeV/c and |η| < 1 for “ZBoson” events as a function of PT(Z) for the “toward” and “transverse” regions. The data are
corrected to the particle level (with errors that include both the statistical error and the systematic
uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle
level (i.e. generator level).
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 46
Z-Boson: “Towards” Region
RDF LHC
Prediction!
"Toward" Charged Particle Density:
dN/dηdφ
"Toward" Charged Particle Density: dN/dηdφ
1.6
RDF Preliminary
PY Tune AW
PY Tune DW
generator level
RDF Preliminary
Drell-Yan
1.96 TeV
"Toward" Charged Density
"Toward" Charged Density
0.8
0.6
0.4
PY64 Tune P329
PY64 Tune S320
0.2
70 < M(pair) < 110 GeV
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
PY Tune DWT
PY Tune DW
generator level
1.2
0.8
PY64 Tune P329
PY64 Tune S320
70 < M(pair) < 110 GeV
0.4
Drell-Yan
14 TeV
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
0
25
50
75
100
125
150
0
25
Lepton-Pair PT (GeV/c)
50
75
100
Lepton-Pair PT (GeV/c)
Z-BosonDirection
Z-BosonDirection
Δφ
Δφ
“Toward”
“Toward”
“Transverse”
“Transverse”
125
Tevatron
LHC
“Transverse”
“Transverse”
“Away”
“Away”
¨ Data at 1.96 TeV on the density of charged particles, dN/dηdφ, with pT > 0.5 GeV/c and |η| < 1 for “ZBoson” events as a function of PT(Z) for the “toward” region from PYTHIA Tune AW, Tune DW, Tune
S320, and Tune P329 at the particle level (i.e. generator level).
¨ Extrapolations of PYTHIA Tune AW, Tune DW, Tune DWT, Tune S320, and Tune P329 to the LHC.
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 47
150
Z-Boson: “Towards” Region
RDF LHC Prediction!
"Toward" Charged PTsum Density: dN/dηdφ
"Toward" Charged PTsum Density: dN/dηdφ
2.0
1.0
generator level
0.8
PY Tune DW
0.6
0.4
PY64 Tune P329
70 < M(pair) < 110 GeV
0.2
Drell-Yan
1.96 TeV
RDF Preliminary
PY Tune AW
"Toward" PTsum Density
"Toward" PTsum Density
RDF Preliminary
PY64 Tune S320
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
PY Tune DWT
generator level
1.6
1.2
PY Tune DW
0.8
PY64 Tune P329
0.4
70 < M(pair) < 110 GeV
PY64 Tune S320
Drell-Yan
14 TeV
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
0.0
0
25
50
75
100
125
150
0
25
Lepton-Pair PT (GeV/c)
50
75
100
Lepton-Pair PT (GeV/c)
Z-BosonDirection
Z-BosonDirection
Δφ
Δφ
“Toward”
“Toward”
“Transverse”
“Transverse”
125
Tevatron
LHC
“Transverse”
“Transverse”
“Away”
“Away”
¨ Data at 1.96 TeV on the charged PTsum density, dPT/dηdφ, with pT > 0.5 GeV/c and |η| < 1 for “Z-Boson”
events as a function of PT(Z) for the “toward” region from PYTHIA Tune AW, Tune DW, Tune S320, and
Tune P329 at the particle level (i.e. generator level).
¨ Extrapolations of PYTHIA Tune AW, Tune DW, Tune DWT, Tune S320, and Tune P329 to the LHC.
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 48
150
LHC Predictions
“Minumum Bias” Collisions
Proton
AntiProton
Charged Particle Density: dN/dη
4.0
RDF Preliminary
Charged Particle Density
I believe we are now in a position to make
some predictions at the LHC!
PY64 Tune P329
generator level
3.0
PY64 Tune S320
2.0
PY Tune A
1.0
Min-Bias
14 TeV
Charged Particles (PT>0.5 GeV/c)
¨ The amount of activity in “min-bias” collisions.
Outgoing Parton
0.0
-8
-6
Δφ
“Toward”
Underlying Event
“Transverse”
Outgoing Parton
“Transverse”
Final-State
Radiation
“Away”
¨ The amount of activity in the “underlying event” in hard
scattering events.
Drell-Yan Production
2
4
6
8
"Transverse" Charged Particle Density: dN/dηdφ
1.6
"Transverse" Charged Density
Underlying Event
0
PseudoRapidity η
Initial-State Radiation
AntiProton
-2
PTmax Direction
PT(hard)
Proton
-4
PY Tune DWT
RDF Preliminary
generator level
1.2
0.8
PY64 Tune P329
PY Tune A
0.4
PY Tune DW
PY64 Tune S320
Min-Bias
14 TeV
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
0
5
10
15
20
25
PTmax (GeV/c)
Z-BosonDirection
Δφ
Lepton
"Toward" Charged Particle Density: dN/dηdφ
“Toward”
RDF Preliminary
AntiProton
Underlying Event
Underlying Event
“Transverse”
“Transverse”
“Away”
Anti-Lepton
¨ The amount of activity in the “underlying event” in DrellYan events.
"Toward" Charged Density
Proton
1.6
PY Tune DWT
PY Tune DW
generator level
1.2
0.8
PY64 Tune P329
PY64 Tune S320
70 < M(pair) < 110 GeV
0.4
Drell-Yan
14 TeV
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
0
25
50
75
100
125
150
Lepton-Pair PT (GeV/c)
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 49
LHC Predictions
“Minumum Bias” Collisions
Proton
AntiProton
Charged Particle Density: dN/dη
4.0
RDF Preliminary
Charged Particle Density
I believe we are now in a position to make
some predictions at the LHC!
PY64 Tune P329
generator level
3.0
PY64 Tune S320
2.0
PY Tune A
1.0
Min-Bias
14 TeV
Charged Particles (PT>0.5 GeV/c)
¨ The amount of activity in “min-bias” collisions.
Outgoing Parton
Underlying Event
1.6
“Toward”
“Transverse”
“Away”
¨ The amount of activity in the “underlying event” in hard
scattering events.
Drell-Yan Production
-2
0
2
4
6
8
"Transverse" Charged Particle Density: dN/dηdφ
If the LHC data are not in
the range shown here then
we learn new physics!
“Transverse”
Final-State
Radiation
-4
PseudoRapidity η
"Transverse" Charged Density
AntiProton
Outgoing Parton
-6
Δφ
Initial-State Radiation
Underlying Event
-8
PTmax Direction
PT(hard)
Proton
0.0
PY Tune DWT
RDF Preliminary
generator level
1.2
0.8
PY64 Tune P329
PY Tune A
0.4
PY Tune DW
PY64 Tune S320
Min-Bias
14 TeV
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
0
5
10
15
20
25
PTmax (GeV/c)
Z-BosonDirection
Δφ
Lepton
"Toward" Charged Particle Density: dN/dηdφ
“Toward”
RDF Preliminary
AntiProton
Underlying Event
Underlying Event
“Transverse”
“Transverse”
“Away”
Anti-Lepton
¨ The amount of activity in the “underlying event” in DrellYan events.
"Toward" Charged Density
Proton
1.6
PY Tune DWT
PY Tune DW
generator level
1.2
0.8
PY64 Tune P329
PY64 Tune S320
70 < M(pair) < 110 GeV
0.4
Drell-Yan
14 TeV
Charged Particles (|η|<1.0, PT>0.5 GeV/c)
0.0
0
25
50
75
100
125
150
Lepton-Pair PT (GeV/c)
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 50
However, I believe that the
better fits to the LEP
fragmentation data at high z
will lead to small improvements
Outgoing Parton
of Tune A at the
Tevatron!
Summary & Conclusions
¨ We are making good progress in understanding and modeling the
“underlying event”.
¨ The new Pythia pT ordered tunes (py64 S320 and py64 P329)
are very similar to Tune A, Tune AW, and Tune DW. At
present the new tunes do not fit the data better than Tune AW
and Tune DW. However, the new tune are theoretically
preferred!
¨ All tunes with the default value PARP(90) = 0.16
are wrong and are overestimating the activity of
min-bias and the underlying event at the LHC!
This includes all the ATLAS tunes!
¨ Need to measure “Min-Bias” and the “underlying
event” at the LHC as soon as possible to see if there is
new QCD physics to be learned!
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Initial-State Radiation
Proton
AntiProton
Underlying Event
Underlying Event
Outgoing Parton
Final-State
Radiation
Hard-Scattering Cut-Off PT0
5
PYTHIA 6.206
ε = 0.25 (Set A))
4
PT0 (GeV/c)
¨ It is clear now that the default value PARP(90) = 0.16 is
not correct and the value should be closer to the Tune A
value of 0.25.
PT(hard)
3
2
ε = 0.16 (default)
1
100
1,000
10,000
100,000
CM Energy W (GeV)
UE&MB@CMS
Page 51
Early LHC Thesis Projects
Thesis 1: Measure dNchg/dη and <PT> versus Nchg
in “min-bias” collisions.
“Minumum Bias” Collisions
Proton
Proton
ChgJet#1 Direction
PTmax Direction
Thesis 2: Measure the “toward”, “away”, and “transverse”
region as a function of PTmax in “min-bias” collisions.
Δφ
Δφ
“Toward”
“Toward”
“Transverse”
Z-Boson Direction
Δφ
“Transverse”
“Transverse”
“Toward”
“Transverse”
“Transverse”
“Away”
“Away”
Thesis 3: Measure the “toward”, “away”, and “transverse”
region as a function of PT(chgjet#1).
“Away”
Outgoing Parton
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Thesis 4: Measure the “toward”, “away”, and “transverse”
region as a function of PT(Z) for Z-boson production.
Underlying Event
Outgoing Parton
Final-State
Radiation
Drell-Yan Production
Proton
Thesis 5: Measure PT(Z) and <pT> versus Nchg
for Z-boson production (all PT(Z), PT(Z) < 10 GeV/c).
“Transverse”
Lepton
Proton
Underlying Event
Underlying Event
Anti-Lepton
Workshop on Early LHC Physics
May 6, 2009
Rick Field – Florida/CDF/CMS
Page 52