Physics in Collision
Min-Bias and the Underlying Event at the LHC
Rick Field
University of Florida
Outline
How well did we do at predicting the behavior of the
“underlying event” at the LHC (900 GeV and 7 TeV)?
How universal are the QCD Monte-Carlo model tunes?
Examine the connection between the “underlying event”
in a hard scattering process (UE) and “min-bias”
collisions (MB).
How well can we predict “min-bias” collisions at the LHC?
CMS
Outgoing Parton
“Minimum Bias” Collisions
PT(hard)
Strange particle and baryon production
Proton
Proton
at the LHC.
Kshort
K+
u s
d s +d s
K-
u s
PIC 2011, Vancouver
August 29, 2011
p
uud
Λ
ud s
Ξ−
Initial-State Radiation
Proton
Proton
Underlying Event
dss
Outgoing Parton
Underlying Event
ATLAS
Final-State
Radiation
UE&MB@CMS
Rick Field – Florida/CDF/CMS
Page 1
“Towards”, “Away”, “Transverse”
“Leading Jet”
Charged Particle Density: dN/dη
ηdφ
φ
5
Jet #1 Direction
∆φ
“Toward”
“Transverse”
“Transverse”
“Away”
Average Charged Density
CDF Run 2 Preliminary
"Away"
data corrected
pyA generator level
4
"Toward"
3
"Leading Jet"
2
Factor of MidPoint
~4.5 R=0.7 |ηη(jet#1)|<2
"Transverse"
1
η|<1.0, PT>0.5 GeV/c)
Charged Particles (|η
0
0
50
100
150
200
250
300
350
400
PT(jet#1) (GeV/c)
CDF data at 1.96 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for
“leading jet” events as a function of the leading jet pT 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 A at the particle level (i.e. generator
level).
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 2
“Towards”, “Away”, “Transverse”
“Leading Jet”
Jet #1 Direction
∆φ
“Toward”
“Transverse”
“Transverse”
“Away”
Charged
PTsum
Density
(GeV/c)
Average
Charged
Density
ChargedPTsum
ParticleDensity:
Density:dPT/dη
dN/dη
η
φ
Charged
dφ
ηdφ
φ
5
100.0
CDFCDF
RunRun
2 Preliminary
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4
data corrected
data corrected
pyA generator level
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1.0
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1
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η(jet#1)|<2
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(|η
|<1.0,PT>0.5
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0 0.1
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(GeV/c)
charged
particles,
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pTη>dφ
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ηGeV/c
| < 1 for
CDF
CDF data
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at 1.96
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|η
η| < 1 forjet”
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and
regions.
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data
are
corrected
to
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that
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level (i.e. generator level).
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 3
Charged Particle Density
Charged Particle Density: dN/dη
ηdφ
φ
Charged Particle Density: dN/dη
ηdφ
φ
3
4
data corrected
pyA generator level
3
Average Charged Density
Average Charged Density
CDF Run 2 Preliminary
"Away"
"Toward"
2
"Leading Jet"
η(jet#1)|<2
MidPoint R=0.7 |η
1
"Transverse"
CDF Run 2 Preliminary
data corrected
pyAW generator level
2
"Drell-Yan Production"
70 < M(pair) < 110 GeV
1
"Transverse"
"Toward"
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
0
"Away"
0
0
20
40
60
80
100
120
140
160
180
200
0
20
40
PT(jet#1) (GeV/c)
Z-Boson Direction
∆φ
Outgoing Parton
High PT Z-Boson Production
PT(hard)
“Toward”
“Transverse”
Underlying Event
“Away”
100
Outgoing Parton
“Toward”
Proton
AntiProton
Underlying Event
80
Initial-State Radiation
Initial-State Radiation
Proton
“Transverse”
60
PT(Z-Boson) (GeV/c)
Jet #1 Direction
∆φ
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
“Transverse”
AntiProton
“Transverse”
“Away”
Outgoing Parton
Final-State
Radiation
Z-boson
CDF data at 1.96 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for “ZBoson” 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 and are compared with PYTHIA Tune AW
and Tune A, respectively, at the particle level (i.e. generator level).
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 4
Charged Particle Density
Charged
Particle
Density:
dN/dη
ηdφ
φ ηdφ
"Away"
Charged
Particle
Density:
dN/dη
φ
"Transverse"
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φ
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Density:Density:
dN/dη
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34
CDFRun
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corrected
data
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levellevel
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0.9
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1.2
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η(jet#1)|<2
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"Z-Boson"
1
0.3
"Transverse"
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ηη|<1.0,
Charged Particles
Particles(|η
(|η
|<1.0,PT>0.5
PT>0.5GeV/c)
GeV/c)
0
0.0
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20
20
40
40
60
60
80
80
100
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120
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140
140
160
160
180
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"Away"
"Drell-Yan Production"
70 < M(pair) < 110 GeV
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200
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140
160
80
180
200
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120
60
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100
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PT(hard)
“Toward”
80
40
Charged
Particles
(|η
|<1.0,
PT>0.5
GeV/c)
η(|η
Charged
Particles
η|<1.0,
PT>0.5
GeV/c)
excluding the lepton-pair
PT(jet#1)
or PT(Z-Boson)
(GeV/c)
PT(Z-Boson)
(GeV/c)
PT(jet#1)
(GeV/c) (GeV/c)
PT(jet#1)
or PT(Z-Boson)
∆φ
"Leading Jet"
data
data corrected
corrected
generator
level theory
pyAW generator
level
“Transverse”
AntiProton
“Transverse”
“Away”
Outgoing Parton
Final-State
Radiation
Z-boson
CDF data at 1.96 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for “ZBoson” 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 and are compared with PYTHIA Tune AW
and Tune A, respectively, at the particle level (i.e. generator level).
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 5
Charged Particle Density
Charged Particle Density: dN/dη
ηdφ
φ
Charged Particle Density: dN/dη
ηdφ
φ
3
3
CMS Preliminary
1.96 TeV
data corrected
pyDW generator level
Average Charged Density
Average Charged Density
CDF Run 2
"Away"
Drell-Yan Production
70 < M(pair) < 110 GeV
2
1
"Transverse"
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
"Toward"
0
0
10
20
30
40
50
60
70
80
90
7 TeV
data corrected
pyDW generator level
"Away"
Drell-Yan Production
60 < M(pair) < 120 GeV
2
"Transverse"
1
"Toward"
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
excluding the lepton-pair
0
100
0
20
40
PT(lepton-pair) GeV/c
Z-Boson Direction
∆φ
High PT Z-Boson Production
60
80
100
PT(lepton-pair) GeV/c
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Outgoing Parton
∆φ
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Proton
AntiProton
“Transverse”
“Transverse”
“Away”
Proton
“Transverse”
“Away”
Z-boson
Z-boson
CDF data at 1.96 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for
Drell-Yan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared
with PYTHIA Tune DW.
CMS data at 7 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 2 for DrellYan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune DW.
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 6
Charged Particle Density
Charged Particle Density: dN/dη
ηdφ
φ
Charged Particle Density: dN/dη
ηdφ
φ
3
3
CMS Preliminary
1.96 TeV
data corrected
pyDW generator level
Average Charged Density
Average Charged Density
CDF Run 2
"Away"
Drell-Yan Production
70 < M(pair) < 110 GeV
2
1
"Transverse"
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
"Toward"
0
0
10
20
30
40
50
60
70
80
90
Outgoing Parton
Initial-State Radiation
“Transverse”
“Transverse”
“Away”
"Away"
"Transverse"
1
"Toward"
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
excluding the lepton-pair
0
100
0
20
40
60
80
100
PT(lepton-pair) GeV/c
High P Z-Boson Production
CDF: Proton-Antiproton
Collisions at 1.96 GeV
∆φ
Lepton Cuts: pT > 20 GeV |η
η| < 1.0
“Toward”
Proton
Mass Cut:
70 < M(lepton-pair) < 110
GeV
AntiProton
Charged Particles: pT > 0.5 GeV/c |η
η| < 1.0
T
CMS
Drell-Yan Production
60 < M(pair) < 120 GeV
2
PT(lepton-pair) GeV/c
Z-Boson Direction
7 TeV
data corrected
pyDW generator level
CMS: Proton-Proton
High P Z-Boson Production
Collisions at 7 GeV
∆φ
Lepton Cuts: pT > 20 GeV |η
η| < 2.4
“Toward”
Mass Cut:Proton
60 < M(lepton-pair) < 120 Proton
GeV
η| < 2.0
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Z-Boson Direction
Outgoing Parton
T
Initial-State Radiation
“Transverse”
“Transverse”
“Away”
Z-boson
Z-boson
CDF data at 1.96 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for
Drell-Yan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared
with PYTHIA Tune DW.
CMS data at 7 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 2 for DrellYan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune DW.
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 7
Charged Particle Density
1.96 TeV
data corrected
pyDW generator level
Charged Particle Density
Average Charged Density
3
Drell-Yan Production
70 < M(pair) < 110 GeV
2
1
Average Charged Density
Large increase in the UE
in going from 1.96 TeV
Charged Particle Density: dN/dη
ηdφ
φ
Charged
Particle Density: dN/dη
ηdφ
φ
"Toward"
Charged Particle Density: dN/dη
ηdφ
φ
to 7 TeV as predicted by
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2
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data corrected
"Away"
pyDW generator level
0.8
Drell-Yan
Production
Charged Particles
(|η
GeV/c)
η|<1.0, PT>0.5
excluding the lepton-pair
0
10
20
30
40
50
60
0
70
PT(lepton-pair) GeV/c
80
20
90
Initial-State Radiation
“Transverse”
“Transverse”
“Away”
"Toward"
Charged Particles (PT>0.5 GeV/c)
0 60
PT(lepton-pair) GeV/c
Outgoing Parton
T
"Transverse"
1
100
40
High P Z-Boson Production
CDF: Proton-Antiproton
Collisions at 1.96 GeV
∆φ
Lepton Cuts: pT > 20 GeV |η
η| < 1.0
“Toward”
Proton
Mass Cut:
70 < M(lepton-pair) < 110
GeV
AntiProton
Charged Particles: pT > 0.5 GeV/c |η
η| < 1.0
Z-Boson Direction
"Away"
Drell-Yan Production
60 < M(pair) < 120 GeV
2
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
excluding the lepton-pair
0
0.0
0
CMS
CDF 1.96 TeV
0.4
"Transverse"
"Toward"
7 TeV
data corrected
CMS pyDW
7 TeV
generator level
2080
40
100
60
80
100
PT(lepton-pair) GeV/c
CMS: Proton-Proton
High P Z-Boson Production
Collisions at 7 GeV
∆φ
Lepton Cuts: pT > 20 GeV |η
η| < 2.4
“Toward”
Mass Cut:Proton
60 < M(lepton-pair) < 120 Proton
GeV
η| < 2.0
Charged Particles: pT > 0.5 GeV/c |η
Z-Boson Direction
Outgoing Parton
T
Initial-State Radiation
“Transverse”
“Transverse”
“Away”
Z-boson
Z-boson
CDF data at 1.96 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for
Drell-Yan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared
with PYTHIA Tune DW.
CMS data at 7 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 2 for DrellYan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune DW.
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 8
Charged PTsum Density
Charged PTsum Density: dPT/dη
ηdφ
φ
10.0
100.0
CDF Run 2 Preliminary
data corrected
pyA generator level
"Toward"
10.0
"Away"
"Transverse"
1.0
"Leading Jet"
MidPoint R=0.7 |η
η(jet#1)|<2
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
0.1
Charged PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
Charged PTsum Density: dPT/dη
ηdφ
φ
CDF Run 2 Preliminary
"Away"
data corrected
pyAW generator level
"Transverse"
1.0
"Toward"
"Drell-Yan Production"
70 < M(pair) < 110 GeV
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
0.1
0
20
40
60
80
100
120
140
160
180
200
0
20
40
PT(jet#1) (GeV/c)
Jet #1 Direction
Outgoing Parton
∆φ
Z-Boson Direction
∆φ
High PT Z-Boson Production
PT(hard)
Proton
“Transverse”
“Transverse”
Underlying Event
“Away”
100
Outgoing Parton
“Toward”
AntiProton
Underlying Event
80
Initial-State Radiation
Initial-State Radiation
“Toward”
60
PT(Z-Boson) (GeV/c)
Proton
“Transverse”
AntiProton
“Transverse”
“Away”
Outgoing Parton
Final-State
Radiation
Z-boson
CDF data at 1.96 TeV on the charged scalar PTsum density, dPT/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for “ZBoson” 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 and are compared with PYTHIA Tune AW
and Tune A, respectively, at the particle level (i.e. generator level).
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 9
Charged PTsum Density
"Away"
Charged
Charged
PTsum
PTsum
Density:
Density:
dPT/dη
dPT/dη
ηdφ
φ ηdφ
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20
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corrected
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1.0
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1.0
"Leading Jet"
MidPoint R=0.7 |η
η(jet#1)|<2
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
Charged Particles (|η
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0.5
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0.00.1
0 0
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100
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120
140
140
160
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Density
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Density(GeV/c)
(GeV/c)
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Density:
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22
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15
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5
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70 < M(pair) < 110 GeV
0
0.1
00
20
40
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60
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∆φ
“Transverse”
“Transverse”
120
60
140
160
80
180
200
100
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“Toward”
AntiProton
Underlying Event
“Away”
100
Initial-State Radiation
Initial-State Radiation
Underlying Event
80
40
High PT Z-Boson Production
PT(hard)
Proton
Charged
ηη|<1.0,
ChargedParticles
Particles(|η
(|η
|<1.0,PT>0.5
PT>0.5GeV/c)
GeV/c)
excluding the lepton-pair
PT(jet#1)
or PT(Z-Boson)
(GeV/c)
PT(Z-Boson)
(GeV/c)
Jet #1 Direction
“Toward”
"Transverse"
"Z-Boson"
10
1.0
(GeV/c)(GeV/c)
PT(jet#1)PT(jet#1)
or PT(Z-Boson)
∆φ
"Away"
"Leading Jet"
data
corrected
data
corrected
pyAW generator
level
generator
level theory
Proton
“Transverse”
AntiProton
“Transverse”
“Away”
Outgoing Parton
Final-State
Radiation
Z-boson
CDF data at 1.96 TeV on the charged scalar PTsum density, dPT/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for “ZBoson” 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 and are compared with PYTHIA Tune AW
and Tune A, respectively, at the particle level (i.e. generator level).
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 10
Charged PTsum Density
Charged PTsum Density: dPT/dη
ηdφ
φ
Charged PTsum Density: dPT/dη
ηdφ
φ
10.0
CDF Run 2
"Away"
1.96 TeV
data corrected
pyDW generator level
"Transverse"
1.0
"Toward"
Drell-Yan Production
70 < M(pair) < 110 GeV
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
Charged PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
10.0
CMS Preliminary
7 TeV
"Transverse"
1.0
"Toward"
CMS
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
excluding the lepton-pair
Drell-Yan Production
60 < M(pair) < 120 GeV
0.1
0.1
0
20
40
60
80
0
100
20
40
Z-Boson Direction
∆φ
High PT Z-Boson Production
60
80
100
PT(lepton-pair) GeV/c
PT(lepton-pair) GeV/c
Z-Boson Direction
Outgoing Parton
∆φ
Initial-State Radiation
High PT Z-Boson Production
Outgoing Parton
Initial-State Radiation
“Toward”
“Toward”
Proton
“Transverse”
"Away"
data corrected
pyDW generator level
Proton
AntiProton
“Transverse”
“Transverse”
“Away”
Proton
“Transverse”
“Away”
Z-boson
Z-boson
CDF data at 1.96 TeV on the charged PTsum density, dPT/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for Drell
Yan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune DW.
CMS data at 7 TeV on the charged PTsum density, dPT/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for Drell-Yan
production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune DW.
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 11
Charged PTsum Density
data corrected
pyDW generator level
data corrected
pyDW generator level
"Toward"
Drell-Yan Production
70 < M(pair) < 110 GeV
1.0
CDF 1.96 TeV
0.5
Charged Particles
(|η
PT>0.5 GeV/c)
η|<1.0,
Drell-Yan
Production
excluding the lepton-pair
0.1
20
40
60
0
80
20
PT(lepton-pair) GeV/c
Z-Boson Direction
∆φ
High PT Z-Boson Production
"Transverse"
1.0
"Toward"
CMS
0
60
100
40
20
80
40
100
Z-Boson Direction
Outgoing Parton
∆φ
60
80
100
PT(lepton-pair) GeV/c
PT(lepton-pair) GeV/c
Initial-State Radiation
High PT Z-Boson Production
Outgoing Parton
Initial-State Radiation
“Toward”
“Toward”
Proton
“Transverse”
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
excluding the lepton-pair
Drell-Yan Production
Charged Particles (PT>0.5 GeV/c)
60 < M(pair) < 120 GeV
0.1
0.0
0
data corrected
pyDW generator level
CMS 7 TeV
"Transverse"
1.0
Charged PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
10.0
Charged PTsum Density (GeV/c)
Large increase in the UE
inCharged
going from
1.96Density:
TeV dPT/dη
Charged
PTsum Density: dPT/dη
ηdφ
φ
PTsum
ηdφ
φ
"Toward"
Charged PTsum Density: dPT/dη
ηdφ
φ
to 7 TeV as predicted by
10.0
1.5
CDF Run
2
CMS Preliminary
1.96
TeV DW! "Away"
7 TeV
RDF Preliminary
PYTHIA
Tune
"Away"
Proton
AntiProton
“Transverse”
“Transverse”
“Away”
Proton
“Transverse”
“Away”
Z-boson
Z-boson
CDF data at 1.96 TeV on the charged PTsum density, dPT/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for Drell
Yan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune DW.
CMS data at 7 TeV on the charged PTsum density, dPT/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for Drell-Yan
production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune DW.
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 12
PYTHIA Tune DW
"Transverse" Charged Particle Density: dN/dη
ηdφ
φ
ηdφ
φ
"Transverse" Charged Particle Density: dN/dη
Charged Particle Density
CMS Preliminary
"Transverse" Charged Density
1.2
7 TeV
data uncorrected
pyDW + SIM
0.8
CMS
900 GeV
0.4
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
1.2
RDF Preliminary
7 TeV
ATLAS corrected data
Tune DW generator level
0.8
ATLAS
900 GeV
0.4
Charged Particles (|η
η|<2.5, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
30
35
40
45
50
0
2
4
6
8
10
CMS preliminary data at 900 GeV and 7 TeV on the “transverse” charged particle density,
dN/dη
ηdφ
φ, as defined by the leading charged
particle jet (chgjet#1) for charged particles
with pT > 0.5 GeV/c and |η
η| < 2. The data are
uncorrected and compared with PYTHIA
Tune DW after detector simulation.
16
18
20
ATLAS preliminary data at 900 GeV and 7
TeV on the “transverse” charged particle
density, dN/dη
ηdφ
φ, as defined by the leading
charged particle (PTmax) for charged particles
with pT > 0.5 GeV/c and |η
η| < 2.5. The data are
corrected and compared with PYTHIA Tune
DW at the generator level.
PT(chgjet#1) Direction
PTmax Direction
∆φ
∆φ
“Toward”
“Toward”
“Transverse”
“Transverse”
“Away”
PIC 2011, Vancouver
August 29, 2011
14
PTmax (GeV/c)
PT(chgjet#1) GeV/c
“Transverse”
12
“Transverse”
“Away”
Rick Field – Florida/CDF/CMS
Page 13
PYTHIA Tune DW
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
1.5
CMS Preliminary
RDF Preliminary
7 TeV
data uncorrected
pyDW + SIM
1.2
PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
1.6
CMS
0.8
900 GeV
0.4
7 TeV
ATLAS corrected data
Tune DW generator level
1.0
ATLAS
900 GeV
0.5
Charged Particles (|η
η|<2.5, PT>0.5 GeV/c)
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
30
35
40
45
50
0
2
CMS preliminary data at 900 GeV and 7
TeV on the “transverse” charged PTsum
density, dPT/dη
ηdφ
φ, as defined by the leading
charged particle jet (chgjet#1) for charged
particles with pT > 0.5 GeV/c and |η
η| < 2.
The data are uncorrected and compared
with PYTHIAPT(chgjet#1)
TuneDirection
DW after detector
simulation.
∆φ
8
10
12
14
16
18
ATLAS preliminary data at 900 GeV and
7 TeV on the “transverse” charged PTsum
density, dPT/dη
ηdφ
φ, as defined by the
leading charged particle (PTmax) for
charged particles with pT > 0.5 GeV/c and
|η
η| < 2.5. The data are corrected and
compared with PYTHIA Tune DW at the
generator level. PTmax Direction∆φ
“Toward”
“Toward”
“Transverse”
“Transverse”
“Away”
PIC 2011, Vancouver
August 29, 2011
6
PTmax (GeV/c)
PT(chgjet#1) (GeV/c)
“Transverse”
4
“Transverse”
“Away”
Rick Field – Florida/CDF/CMS
Page 14
20
PYTHIA Tune DW
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
1.5
CMS Preliminary
1.2
RDF Preliminary
7 TeV
data uncorrected
pyDW + SIM
CMS
0.8
PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
1.6
7 TeV
ATLAS corrected data
Tune DW generator level
1.0
900 GeV
ATLAS
Overall PYTHIA Tune DW
is in amazingly
good agreement with the Charged Particles (|ηη|<2.5, PT>0.5 GeV/c)
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
0.0
Tevatron Jet production 0.0
and
Drell-Yan
data
0
2
4
6
8
10
12
14
16
18
20
0
5
10
15
20
25
30
35
40
45
50
and
did a very good job in predicting thePTmax (GeV/c)
PT(chgjet#1)
(GeV/c)
LHC Jet production and Drell-Yan data!
ATLAS preliminary data at 900 GeV and
CMS preliminary data at 900 GeV and 7
(although
not
perfect)
7 TeV on the “transverse” charged PTsum
TeV on the “transverse” charged PTsum
900 GeV
0.4
density, dPT/dη
ηdφ
φ, as defined by the leading
charged particle jet (chgjet#1) for charged
particles with pT > 0.5 GeV/c and |η
η| < 2.
The data are uncorrected and compared
with PYTHIAPT(chgjet#1)
TuneDirection
DW after detector
simulation.
∆φ
0.5
density, dPT/dη
ηdφ
φ, as defined by the
leading charged particle (PTmax) for
charged particles with pT > 0.5 GeV/c and
|η
η| < 2.5. The data are corrected and
compared with PYTHIA Tune DW at the
generator level. PTmax Direction∆φ
“Toward”
“Transverse”
“Toward”
“Transverse”
“Transverse”
“Away”
PIC 2011, Vancouver
August 29, 2011
“Transverse”
“Away”
Rick Field – Florida/CDF/CMS
Page 15
PYTHIA Tune Z1
All my previous tunes (A, DW, DWT, D6,
D6T, CW, X1, and X2) were PYTHIA 6.4
tunes using the old Q2-ordered parton
showers and the old MPI model (really 6.2
tunes)!
I believe that it is time to move to PYTHIA
6.4 (pT-ordered parton showers and new
MPI model)!
Tune Z1: I started with the parameters of
ATLAS Tune AMBT1, but I changed LO* to
CTEQ5L and I varied PARP(82) and PARP(90)
to get a very good fit of the CMS UE data at 900
GeV and 7 TeV.
The ATLAS Tune AMBT1 was designed to fit
the inelastic data for Nchg ≥ 6 and to fit the
PTmax UE data with PTmax > 10 GeV/c. Tune
AMBT1 is primarily a min-bias tune, while
Tune Z1 is a UE tune!
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
PARP(90)
PARP(82)
Color
Connections
Diffraction
Outgoing Parton
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
Underlying Event
Final-State
Radiation
UE&MB@CMS
Page 16
PYTHIA Tune Z1
Tune Z1
(R. Field CMS)
Tune AMBT1
(ATLAS)
CTEQ5L
LO*
PARP(82) – MPI Cut-off
1.932
2.292
PARP(89) – Reference energy, E0
1800.0
1800.0
PARP(90) – MPI Energy Extrapolation
0.275
0.25
PARP(77) – CR Suppression
1.016
1.016
PARP(78) – CR Strength
0.538
0.538
0.1
0.1
PARP(83) – Matter fraction in core
0.356
0.356
PARP(84) – Core of matter overlap
0.651
0.651
PARP(62) – ISR Cut-off
1.025
1.025
PARP(93) – primordial kT-max
10.0
10.0
MSTP(81) – MPI, ISR, FSR, BBR model
21
21
MSTP(82) – Double gaussion matter distribution
4
4
MSTP(91) – Gaussian primordial kT
1
1
MSTP(95) – strategy for color reconnection
6
6
Parameter
Parton Distribution Function
Parameters not
shown are the
PYTHIA 6.4 defaults!
PARP(80) – Probability colored parton from BBR
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 17
CMS UE Data
ηdφ
φ
"Transverse" Charged PTsum Density: dPT/dη
"Transverse" Charged Particle Density: dN/dη
ηdφ
φ
2.0
CMS Preliminary
CMS Preliminary
data corrected
Tune Z1 generator level
7 TeV
PTsum Density (GeV/c)
Charged Particle Density
1.6
1.2
0.8
900 GeV
CMS
0.4
Tune Z1
data corrected
Tune Z1 generator level
1.6
7 TeV
1.2
CMS
0.8
900 GeV
Tune Z1
0.4
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
0.0
0.0
0
10
20
30
40
50
60
70
80
90
100
0
10
PT(chgjet#1) GeV/c
PIC 2011, Vancouver
August 29, 2011
30
40
50
60
70
80
90
100
PT(chgjet#1) GeV/c
CMS preliminary data at 900 GeV and 7
TeV on the “transverse” charged particle
density, dN/dη
ηdφ
φ, as defined by the leading
charged particle jet (chgjet#1) for charged
particles with pT > 0.5 GeV/c and |η
η| < 2.0.
The data are corrected and compared with
PYTHIA Tune Z1 at the generator level.
CMS corrected
data!
20
CMS preliminary data at 900 GeV and 7
TeV on the “transverse” charged PTsum
density, dPT/dη
ηdφ
φ, as defined by the leading
charged particle jet (chgjet#1) for charged
particles with pT > 0.5 GeV/c and |η
η| < 2.0.
The data are corrected and compared with
PYTHIA Tune Z1 at the generator level.
Very nice agreement!
Rick Field – Florida/CDF/CMS
CMS corrected
data!
Page 18
ATLAS UE Data
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
"Transverse" Charged Particle Density: dN/dη
ηdφ
φ
1.5
RDF Preliminary
RDF Preliminary
7 TeV
ATLAS corrected data
Tune Z1 generator level
PTsum Density (GeV/c)
"Transverse" Charged Density
1.2
0.8
ATLAS
900 GeV
0.4
Tune Z1
7 TeV
ATLAS corrected data
Tune Z1 generator level
1.0
ATLAS
900 GeV
0.5
Tune Z1
Charged Particles (|η
η|<2.5, PT>0.5 GeV/c)
Charged Particles (|η
η|<2.5, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
0
5
10
15
20
25
PTmax (GeV/c)
PTmax (GeV/c)
ATLAS published data at 900 GeV and 7
TeV on the “transverse” charged particle
density, dN/dη
ηdφ
φ, as defined by the leading
charged particle (PTmax) for charged
particles with pT > 0.5 GeV/c and |η
η| < 2.5.
The data are corrected and compared with
PYTHIA Tune Z1 at the generator level.
ATLAS published data at 900 GeV and 7
TeV on the “transverse” charged PTsum
density, dPT/dη
ηdφ
φ, as defined by the leading
charged particle (PTmax) for charged
particles with pT > 0.5 GeV/c and |η
η| < 2.5.
The data are corrected and compared with
PYTHIA Tune Z1 at the generrator level.
ATLAS publication – arXiv:1012.0791
December 3, 2010
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 19
CMS-ATLAS UE Data
ηdφ
φ
"Transverse" Charged Particle Density: dN/dη
ηdφ
φ
"Transverse" Charged Particle Density: dN/dη
1.6
RDF Preliminary
RDF Preliminary
CMS: Chgjet#1
data corrected
Tune Z1 generator level
Charged Particle Density
Charged Particle Density
1.6
1.2
0.8
CMS (red)
ATLAS (blue)
ATLAS: PTmax
0.4
Tune Z1
data corrected
Tune Z1 generator level
1.2
0.8
CMS (red)
ATLAS (blue)
Tune Z1
0.4
Charged Particles (PT > 0.5 GeV/c)
7 TeV
Charged Particles (PT > 0.5 GeV/c)
7 TeV
0.0
0.0
0
5
10
15
20
25
30
0
10
20
30
40
50
60
70
80
90
100
PTmax or PT(chgjet#1) (GeV/c)
PTmax or PT(chgjet#1) (GeV/c)
CMS preliminary data at 7 TeV on the “transverse” charged particle density, dN/dη
ηdφ
φ, as
defined by the leading charged particle jet (chgjet#1) for charged particles with pT > 0.5 GeV/c
and |η
η| < 2.0 together with the ATLAS published data at 7 TeV on the “transverse” charged
particle density, dN/dη
ηdφ
φ, as defined by the leading charged particle (PTmax) for charged
particles with pT > 0.5 GeV/c and |η
η| < 2.5 The data are corrected and compared with PYTHIA
Tune Z1 at the generator level.
Amazing agreement!
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 20
ALICE UE Data
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
"Transverse" Charged Particle Density: dN/dη
ηdφ
φ
1.5
RDF Preliminary
RDF Preliminary
7 TeV
ALICE corrected data
Tune Z1 generator level
PTsum Density (GeV/c)
"Transverse" Charged Density
1.2
0.8
900 GeV
0.4
ALICE
Tune Z1
7 TeV
ALICE corrected data
Tune Z1 generator level
1.0
900 GeV
0.5
ALICE
Tune Z1
Charged Particles (|η
η|<0.8, PT>0.5 GeV/c)
Charged Particles (|η
η|<0.8, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
0
5
ALICE preliminary data at 900 GeV and 7
TeV on the “transverse” charged particle
density, dN/dη
ηdφ
φ, as defined by the leading
charged particle (PTmax) for charged
particles with pT > 0.5 GeV/c and |η
η| < 0.8.
The data are corrected and compared with
PYTHIA Tune Z1 at the generator level.
PIC 2011, Vancouver
August 29, 2011
15
20
25
PTmax (GeV/c)
PTmax (GeV/c)
I read the points off
with a ruler!
10
ALICE preliminary data at 900 GeV and 7
TeV on the “transverse” charged PTsum
density, dPT/dη
ηdφ
φ, as defined by the leading
charged particle (PTmax) for charged
particles with pT > 0.5 GeV/c and |η
η| < 0.8.
The data are corrected and compared with
PYTHIA Tune Z1 at the generrator level.
ALICE UE Data: Talk by S. Vallero
MPI@LHC 2010 Glasgow, Scotland
November 30, 2010
Rick Field – Florida/CDF/CMS
Page 21
PYTHIA Tune Z1
"Transverse"Charged
ChargedParticle
ParticleDensity:
Density:dN/dη
dN/dη
dφ
"Transverse"
ηηdφ
φφ
1.2
"Transverse" Charged Particle Density: dN/dη
ηdφ
φ
1.5
CMSPreliminary
Preliminary
RDF
RDF Preliminary
data
corrected
data
corrected
Tune generator
Z1 generator
level
pyZ1
level
CMS 7 TeV7 TeV
1.0
CDF 1.96 TeV
0.8
900 GeV
0.5
0.4
CMS 900 GeV
Tune Z1
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
Charged Particles (PT>0.5 GeV/c)
0.0
0.0
Charged Particle Density
Charged
Charged Particle
Particle Density
Density
1.6
1.5
data corrected
pyZ1 generator level
CMS 7 TeV
1.0
CDF 1.96 TeV
0.5
CMS 900 GeV
Tune Z1
Charged Particles (PT>0.5 GeV/c)
0.0
00
10
20
20
30
40
40
50
60
60
70
80
80
90
100
100
0
50
PT(chgjet#1)
GeV/c
PT(chgjet#1
or jet#1)
GeV/c
CMS data at 900 GeV on the “transverse”
charged particle density, dN/dη
ηdφ
φ, as
defined by the leading charged particle jet
(chgjet#1) for charged particles with pT >
0.5 GeV/c and |η
η| < 2.0. The data are
corrected and compared with PYTHIA
Tune Z1 at the generator level.
PIC 2011, Vancouver
August 29, 2011
100
150
200
250
300
PT(chgjet#1 or jet#1) GeV/c
CDF data at 1.96 TeV on the “transverse”
charged particle density, dN/dη
ηdφ
φ, as
defined by the leading calorimeter jet (jet#1)
for charged particles with pT > 0.5 GeV/c
and |η
η| < 1.0. The data are corrected and
compared with PYTHIA Tune Z1 at the
generator level.
Rick Field – Florida/CDF/CMS
Page 22
PYTHIA Tune Z1
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
2.0
2.0
RDF Preliminary
datacorrected
corrected
data
Tune
generator
level
pyZ1 Z1
generator
level
1.6
7 TeV
CMS
7 TeV
1.2
PTsum Density (GeV/c)
PTsum Density (GeV/c)
CMSPreliminary
Preliminary
RDF
CDF 1.96 TeV
0.8
900 GeV
CMS 900 GeV
Tune Z1
0.4
CMS 7 TeV
data corrected
pyZ1 generator level
1.6
CDF 1.96 TeV
1.2
0.8
Tune Z1
CMS 900 GeV
0.4
Charged Particles (PT>0.5 GeV/c)
Charged Particles (PT>0.5 GeV/c)
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
0.0
0.0
0
10
20
30
40
50
60
70
80
90
100
0
100
150
200
250
300
PT(chgjet#1 or jet#1) GeV/c
PT(chgjet#1
or jet#1)
GeV/c
PT(chgjet#1)
GeV/c
CMS data at 900 GeV and 7 TeV on the
“transverse” charged PTsum density,
dPT/dη
ηdφ
φ, as defined by the leading charged
particle jet (chgjet#1) for charged particles
with pT > 0.5 GeV/c and |η
η| < 2.0. The data
are corrected and compared with PYTHIA
Tune Z1 at the generator level.
PIC 2011, Vancouver
August 29, 2011
50
CDF data at 1.96 TeV on the “transverse”
charged PTsum density, dPT/dη
ηdφ
φ, as
defined by the leading calorimeter jet (jet#1)
for charged particles with pT > 0.5 GeV/c
and |η
η| < 1.0. The data are corrected and
compared with PYTHIA Tune Z1 at the
generator level.
Rick Field – Florida/CDF/CMS
Page 23
PYTHIA Tune Z1
Charged Particle Density: dN/dη
ηdφ
φ
Charged Particle Density: dN/dη
ηdφ
φ
3
3
CMS Preliminary
1.96 TeV
data corrected
pyZ1 generator level
Average Charged Density
Average Charged Density
CDF Run 2
"Away"
Drell-Yan Production
70 < M(pair) < 110 GeV
2
1
"Transverse"
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
"Toward"
0
0
10
20
30
40
50
60
70
80
90
∆φ
High PT Z-Boson Production
"Transverse"
1
"Toward"
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
excluding the lepton-pair
0
100
0
20
40
60
80
100
PT(lepton-pair) GeV/c
Z-Boson Direction
Outgoing Parton
∆φ
Initial-State Radiation
High PT Z-Boson Production
Outgoing Parton
Initial-State Radiation
“Toward”
“Toward”
Proton
“Transverse”
"Away"
Drell-Yan Production
60 < M(pair) < 120 GeV
2
PT(lepton-pair) GeV/c
Z-Boson Direction
CMS
7 TeV
data corrected
pyZ1 generator level
Proton
AntiProton
“Transverse”
“Transverse”
“Away”
Proton
“Transverse”
“Away”
Z-boson
Z-boson
CDF data at 1.96 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for
Drell-Yan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared
with PYTHIA Tune Z1.
CMS data at 7 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 2 for DrellYan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune Z1.
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 24
PYTHIA Tune Z1
Tune Z1 describes the
energy dependence
Charged Particle Density: dN/dη
ηdφ
φ
Charged
Particle Density: dN/dη
ηdφ
φ
"Toward"
Charged Particle Density: dN/dη
ηdφ
φ
fairly well!
3
1.2
Drell-Yan Production
70 < M(pair) < 110 GeV
2
1
CMS Preliminary
RDF Preliminary
1.96 TeV
data corrected
pyZ1 generator level
Charged Particle Density
Average Charged Density
CDF Run 2
Average Charged Density
3
data corrected
"Away"
pyZ1 generator level
0.8
Charged Particles
(|η
PT>0.5 GeV/c)
η|<1.0, Production
Drell-Yan
excluding the lepton-pair
0
10
20
30
40
50
60
0
70
80
20
PT(lepton-pair) GeV/c
Z-Boson Direction
∆φ
High PT Z-Boson Production
90
"Transverse"
1
"Toward"
0
100
40
0 60
40
100
60
80
100
PT(lepton-pair) GeV/c
Z-Boson Direction
∆φ
Initial-State Radiation
High PT Z-Boson Production
Outgoing Parton
Initial-State Radiation
“Toward”
“Toward”
Proton
“Transverse”
2080
PT(lepton-pair) GeV/c
Outgoing Parton
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
excluding the lepton-pair
Charged Particles (PT>0.5 GeV/c)
0.0
0
"Away"
Drell-Yan Production
60 < M(pair) < 120 GeV
2
CDF 1.96 TeV
0.4
"Transverse"
"Toward"
CMS
7 TeV
data corrected
pyZ1
generator level
CMS 7
TeV
Proton
AntiProton
“Transverse”
“Transverse”
“Away”
Proton
“Transverse”
“Away”
Z-boson
Z-boson
CDF data at 1.96 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for
Drell-Yan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared
with PYTHIA Tune Z1.
CMS data at 7 TeV on the density of charged particles, dN/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 2 for DrellYan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune Z1.
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 25
PYTHIA Tune Z1
Charged PTsum Density: dPT/dη
ηdφ
φ
Charged PTsum Density: dPT/dη
ηdφ
φ
10.0
CDF Run 2
"Away"
1.96 TeV
data corrected
pyZ1 generator level
"Transverse"
1.0
"Toward"
Drell-Yan Production
70 < M(pair) < 110 GeV
Charged Particles (|η
η|<1.0, PT>0.5 GeV/c)
excluding the lepton-pair
0.1
Charged PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
10.0
CMS Preliminary
7 TeV
"Away"
data corrected
pyZ1 generator level
"Transverse"
1.0
"Toward"
CMS
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
excluding the lepton-pair
Drell-Yan Production
60 < M(pair) < 120 GeV
0.1
0
20
40
60
80
100
0
20
40
PT(lepton-pair) GeV/c
Z-Boson Direction
∆φ
High PT Z-Boson Production
80
100
PT(lepton-pair) GeV/c
Z-Boson Direction
Outgoing Parton
∆φ
Initial-State Radiation
High PT Z-Boson Production
Outgoing Parton
Initial-State Radiation
“Toward”
“Toward”
Proton
“Transverse”
60
Proton
AntiProton
“Transverse”
“Transverse”
“Away”
Proton
“Transverse”
“Away”
Z-boson
Z-boson
CDF data at 1.96 TeV on the charged PTsum density, dPT/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for Drell
Yan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune Z1.
CMS data at 7 TeV on the charged PTsum density, dPT/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 2 for Drell-Yan
production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune Z1.
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 26
PYTHIA Tune Z1
Charged PTsum Density: dPT/dη
ηdφ
φ
Charged
PTsum Density: dPT/dη
ηdφ
φ
"Toward"
Charged PTsum Density: dPT/dη
ηdφ
φ
1.96 TeV
data corrected
pyZ1 generator level
"Away"
RDF
Preliminary
data corrected
pyZ1 generator level
"Toward"
Drell-Yan Production
70 < M(pair) < 110 GeV
1.0
CDF 1.96 TeV
0.5
Charged Particles
(|η
PT>0.5 GeV/c)
η|<1.0,
Drell-Yan
Production
excluding the lepton-pair
0.1
20
40
60
0
80
20
PT(lepton-pair) GeV/c
Z-Boson Direction
∆φ
"Away"
"Transverse"
1.0
"Toward"
CMS
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
excluding the lepton-pair
Drell-Yan Production
Charged Particles (PT>0.5 GeV/c)
60 < M(pair) < 120 GeV
High PT Z-Boson Production
100
40
0
60
20
80
40
100
Z-Boson Direction
Outgoing Parton
∆φ
60
80
100
PT(lepton-pair) GeV/c
PT(lepton-pair) GeV/c
Initial-State Radiation
High PT Z-Boson Production
Outgoing Parton
Initial-State Radiation
“Toward”
“Toward”
Proton
“Transverse”
7 TeV
data corrected
pyZ1 generator level
0.1
0.0
0
CMS Preliminary
CMS 7 TeV
"Transverse"
1.0
Charged PTsum Density (GeV/c)
10.0
1.5
CDF Run 2
Charged PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
10.0
Proton
AntiProton
“Transverse”
“Transverse”
“Away”
Proton
“Transverse”
“Away”
Z-boson
Z-boson
CDF data at 1.96 TeV on the charged PTsum density, dPT/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 1 for Drell
Yan production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune Z1.
CMS data at 7 TeV on the charged PTsum density, dPT/dη
ηdφ
φ, with pT > 0.5 GeV/c and |η
η| < 2 for Drell-Yan
production as a function of PT(Z) for the “toward”, “away”, and “transverse” regions compared with
PYTHIA Tune Z1.
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 27
PYTHIA Tune Z1
"Transverse" Charged Particle Density: dN/dη
ηdφ
φ
"Transverse" Charged Particle Density: dN/dη
ηdφ
φ
1.2
1.5
RDF Preliminary
data corrected
pyZ1 generator level
Charged Particle Density
Charged Particle Density
RDF Preliminary
CMS 7 TeV
1.0
CDF 1.96 TeV
0.5
CMS 900 GeV
Tune Z1
0.8
CDF 1.96 TeV
0.4
Tune Z1
0.0
0
20
40
60
80
100
0
20
PT(chgjet#1 or jet#1) GeV/c
3.0
Charged Particle Density
1.2
0.8
Drell-Yan Production
0.4
80
100
RDF Preliminary
Chgjet Production
7 TeV
data corrected
pyZ1 generator level
60
"Away" Charged Particle Density: dN/dη
ηdφ
φ
1.6
CMS Preliminary
40
PT(lepton-pair) GeV/c
"Transverse" Charged Particle Density: dN/dη
ηdφ
φ
Charged Particle Density
Charged Particles (PT>0.5 GeV/c)
Drell-Yan Production
Charged Particles (PT>0.5 GeV/c)
0.0
CMS 7 TeV
data corrected
pyZ1 generator level
Tune Z1
data corrected
pyZ1 generator level
CDF 1.96 TeV
2.0
CMS 7 TeV
1.0
Tune Z1
Drell-Yan Production
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
Charged Particles (PT>0.5 GeV/c)
0.0
0.0
0
10
20
30
40
50
60
70
80
90
100
0
40
60
80
100
PT(lepton-pair) GeV/c
PT(chgjet#1) or PT(lepton-pair) GeV/c
PIC 2011, Vancouver
August 29, 2011
20
Rick Field – Florida/CDF/CMS
Page 28
PYTHIA Tune Z1
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
2.0
Charged PTsum Density (GeV/c)
2.0
PTsum Density (GeV/c)
RDF Preliminary
data corrected
pyZ1 generator level
1.6
CMS 7 TeV
1.2
CDF 1.96 TeV
0.8
CMS 900 GeV
Tune Z1
0.4
Charged Particles (PT>0.5 GeV/c)
RDF Preliminary
Tune Z1
data corrected
pyZ1 generator level
1.5
CMS 7 TeV
1.0
CDF 1.96 TeV
0.5
0.0
0.0
0
10
20
30
40
50
60
70
80
90
0
100
10
20
30
50
60
70
80
90
100
"Away" Charged PTsum Density: dPT/dη
ηdφ
φ
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
10.0
CMS Preliminary
7 TeV
data corrected
pyZ1 generator level
RDF Preliminary
What about Min-Bias?
Chgjet Production
Charged PTsum Density (GeV/c)
2.0
40
PT(lepton-pair) GeV/c
PT(chgjet#1 or jet#1) GeV/c
Charged PTsum Density (GeV/c)
Charged Particles (PT>0.5 GeV/c)
Drell-Yan Production
1.5
1.0
Tune Z1
0.5
Drell-Yan Production
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
data corrected
pyZ1 generator level
8.0
CDF 1.96 TeV
Drell-Yan Production
6.0
CMS 7 TeV
4.0
Tune Z1
2.0
Charged Particles (PT>0.5 GeV/c)
0.0
0.0
0
10
20
30
40
50
60
70
80
90
100
0
10
30
40
50
60
70
80
90
PT(lepton-pair) GeV/c
PT(chgjet#1) or PT(lepton-pair) GeV/c
PIC 2011, Vancouver
August 29, 2011
20
Rick Field – Florida/CDF/CMS
Page 29
100
PYTHIA Tune Z1
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
"Transverse" Charged PTsum Density: dPT/dη
ηdφ
φ
2.0
Charged PTsum Density (GeV/c)
2.0
PTsum Density (GeV/c)
RDF Preliminary
data corrected
pyZ1 generator level
1.6
CMS 7 TeV
1.2
CDF 1.96 TeV
0.8
CMS 900 GeV
Tune Z1
0.4
Tune Z1
data corrected
pyZ1 generator level
1.5
CMS 7 TeV
1.0
CDF 1.96 TeV
0.5
Charged Particles (PT>0.5 GeV/c)
Drell-Yan Production
Overall amazingly good agreement
0.0
0.0
with
0
10
20
30
40
50
60
70
80
0
10
20
30
40
50
60
70
80the90LHC
100 and Tevatron
PT(chgjet#1 or jet#1) GeV/c
Jet production and Drell-Yan! PT(lepton-pair) GeV/c
not perfect yet)
"Away" Charged PTsum Density: dPT/dη
ηdφ
φ
"Transverse" Charged PTsum Density:(although
dPT/dη
ηdφ
φ
10.0
2.0
CMS Preliminary
RDF Preliminary
What about Min-Bias?
7 TeV Chgjet Production
Charged PTsum Density (GeV/c)
Charged Particles (PT>0.5 GeV/c)
Charged PTsum Density (GeV/c)
RDF Preliminary
data corrected
pyZ1 generator level
1.5
1.0
Tune Z1
0.5
Drell-Yan Production
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
data corrected
pyZ1 generator level
8.0
90
100
CDF 1.96 TeV
Drell-Yan Production
6.0
CMS 7 TeV
4.0
Tune Z1
2.0
Charged Particles (PT>0.5 GeV/c)
0.0
0.0
0
10
20
30
40
50
60
70
80
90
100
0
10
30
40
50
60
70
80
90
PT(lepton-pair) GeV/c
PT(chgjet#1) or PT(lepton-pair) GeV/c
PIC 2011, Vancouver
August 29, 2011
20
Rick Field – Florida/CDF/CMS
Page 30
100
The Inelastic Non-Diffractive
Cross-Section
Occasionally one of
the parton-parton
collisions is hard
(pT > ≈2 GeV/c)
Proton
Proton
Majority of “minbias” events!
Proton
“Semi-hard” partonparton collision
(pT < ≈2 GeV/c)
Proton
+
Proton
+
Proton
Proton
Proton
+
Proton
Proton
+…
Multiple-parton
interactions (MPI)!
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 31
The “Underlying Event”
Select inelastic non-diffractive events
that contain a hard scattering
Proton
Hard parton-parton
collisions is hard
(pT > ≈2 GeV/c)
Proton
1/(pT)4→ 1/(pT2+pT02)2
The “underlying-event” (UE)!
Proton
Given that you have one hard
scattering it is more probable to
have MPI! Hence, the UE has
more activity than “min-bias”.
PIC 2011, Vancouver
August 29, 2011
Proton
+
+
Proton
Proton
Rick Field – Florida/CDF/CMS
“Semi-hard” partonparton collision
(pT < ≈2 GeV/c)
Proton
Proton
+…
Multiple-parton
interactions (MPI)!
Page 32
Allow leading hard
scattering to go to
zero pT with same
cut-off as the MPI!
Model of σND
Proton
Proton
Proton
Proton
Proton
+
Proton
“Semi-hard” partonparton collision
(pT < ≈2 GeV/c)
1/(pT)4→ 1/(pT2+pT02)2
Model of the inelastic nondiffractive cross section!
+
Proton
Proton
Proton
+
Proton
Proton
+…
Multiple-parton
interactions (MPI)!
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 33
UE Tunes
Allow primary hard-scattering to
go to pT = 0 with same cut-off!
“Underlying Event”
Fit the “underlying
event” in a hard
scattering process.
Proton
Proton
1/(pT)4→ 1/(pT2+pT02)2
“Min-Bias”
“Min-Bias” (add
(ND)single & double diffraction)
Proton
Predict MB (ND)!
Proton
+
+
Proton
Proton
Proton
Single Diffraction
Predict MB (IN)!
PIC 2011, Vancouver
August 29, 2011
+…
Proton
+
Proton
Proton
Double Diffraction
M2
M
Rick Field – Florida/CDF/CMS
M1
Page 34
Min-Bias Collisions
Charged Particle Density: dN/dη
η
Charged Particle Density: dN/dη
η
6
CMS Data
ALICE Data
PYTHIA Tune Z1
PYTHIA Tune Z1
Charged Particle Density
Charged Particle Density
8
6
NSD = ND + DD
4
Tune Z1
CMS
2
pyZ1 ND = dashed
pyZ1 NSD = solid
7 TeV
NSD (all pT)
4
2
Tune Z1
INEL (all pT)
0
ALICE
INEL = NSD + SD
pyZ1 NSD = dashed
pyZ1 INEL = solid
900 GeV
0
-4
-3
-2
-1
0
1
2
3
4
-4
-3
Pseudo-Rapidity η
-2
-1
0
1
2
3
Pseudo-Rapidity η
CMS NSD data on the charged particle
rapidity distribution at 7 TeV compared
with PYTHIA Tune Z1. The plot shows
the average number of particles per NSD
collision per unit η, (1/NNSD) dN/dη
η.
ALICE NSD data on the charged particle
rapidity distribution at 900 GeV compared
with PYTHIA Tune Z1. The plot shows
the average number of particles per INEL
collision per unit η, (1/NINEL) dN/dη
η.
“Minimum Bias” Collisions
Okay not perfect, but remember
Proton
we know that SD and DD are not modeled well!
Proton
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 35
4
MB versus UE
Divide be 2π
π
Charged Particle Density: dN/dη
η
2.5
8
CMS Data
CMS Data
PYTHIA Tune Z1
PYTHIA Tune Z1
Charged Particle Density
Charged Particle Density
Charged Particle Density: dN/dη
ηdφ
φ
6
NSD = ND + DD
4
Tune Z1
CMS
2
pyZ1 ND = dashed
pyZ1 NSD = solid
7 TeV
NSD (all pT)
2.0
1.5
1.0
0.5
pyZ1 ND = dashed
7 TeV
NSD (all pT)
pyZ1 NSD = solid
0.0
0
-4
-3
-2
-1
0
1
2
3
4
-4
-3
-2
-1
0
1
2
3
4
Pseudo-Rapidity η
Pseudo-Rapidity η
CMS NSD data on the charged particle
CMS NSD data on the charged particle rapidity
rapidity distribution at 7 TeV compared
distribution at 7 TeV compared with PYTHIA
with PYTHIA Tune Z1. The plot shows
Tune Z1. The plot shows the average number of
the average number of charged particles
charged particles per NSD collision per unit η−φ,
per NSD collision per unit η, (1/NNSD)
(1/NNSD) dN/dη
ηdφ
φ.
dN/dη
η.
“Minimum Bias” Collisions
Proton
PIC 2011, Vancouver
August 29, 2011
Proton
Rick Field – Florida/CDF/CMS
Page 36
MB versus UE
Charged Particle Density: dN/dη
ηdφ
φ
ηdφ
φ
Transverse Charged Particle Density: dN/dη
2.5
RDF Preliminary
CMS Data
PYTHIA Tune Z1
PYTHIA Tune Z1
Charged Particle Density
Charged Particle Density
2.5
2.0
Factor of 2!
1.5
1.0
Charged Particles (|η
η| < 2, all pT)
0.5
Tune Z1
CMS
2.0
Tune Z1
1.0
0.5
7 TeV ND
pyZ1 ND = dashed
7 TeV
NSD (all pT)
0.0
NSD = ND + DD
1.5
pyZ1 NSD = solid
0.0
0
5
10
15
20
25
-4
-3
-2
-1
0
1
2
3
Pseudo-Rapidity η
PT max (GeV/c)
Shows the density of charged particles in
the “transverse” region as a function of
PTmax for charged particles (All pT, |η
η| <
2) at 7 TeV from PYTHIA Tune Z1.
Outgoing Parton
CMS NSD data on the charged particle rapidity
distribution at 7 TeV compared with PYTHIA
Tune Z1. The plot shows the average number of
charged particles per NSD collision per unit η−φ,
(1/NNSD) dN/dη
ηdφ
φ.
PT(hard)
“Minimum Bias” Collisions
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
PIC 2011, Vancouver
August 29, 2011
4
Proton
Underlying Event
Proton
Final-State
Radiation
Rick Field – Florida/CDF/CMS
Page 37
MB versus UE
Charged Particle Density: dN/dη
ηdφ
φ
ηdφ
φ
"Transverse" Charged Particle Density: dN/dη
2.5
CMS Data
ATLAS
2.0
Charged Particle Density
"Transverse" Charged Density
2.5
Factor of 2!
1.5
RDF Preliminary
1.0
ATLAS corrected data
Tune Z1 generator level
0.5
Charged Particles (pT > 0.1 GeV/c, |η
η|<2.5)
7 TeV
CMS
PYTHIA Tune Z1
2.0
Tune Z1
1.0
0.5
pyZ1 ND = dashed
7 TeV
NSD (all pT)
0.0
NSD = ND + DD
1.5
pyZ1 NSD = solid
0.0
0
2
4
6
8
10
12
14
16
18
20
-4
-3
PTmax (GeV/c)
-2
-1
0
1
2
3
Pseudo-Rapidity η
ATLAS data on the density of charged
particles in the “transverse” region as a
function of PTmax for charged particles
(pT > 0.1 GeV/c, |η
η| < 2.5) at 7 TeV
compared with PYTHIA Tune Z1.
Outgoing Parton
CMS NSD data on the charged particle rapidity
distribution at 7 TeV compared with PYTHIA
Tune Z1. The plot shows the average number of
charged particles per NSD collision per unit η−φ,
(1/NNSD) dN/dη
ηdφ
φ.
PT(hard)
“Minimum Bias” Collisions
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
PIC 2011, Vancouver
August 29, 2011
4
Proton
Underlying Event
Proton
Final-State
Radiation
Rick Field – Florida/CDF/CMS
Page 38
NSD Multiplicity Distribution
Charged Multiplicity Distribution
1.0E-01
RDF Preliminary
data CMS NSD
pyZ1 generator level
Difficult to produce
enough events with
large multiplicity!
CMS
Probability
1.0E-02
7 TeV
900 GeV
1.0E-03
Charged Particles
(all PT, |η
η|<2.0)
Tune Z1
1.0E-04
0
20
40
60
80
100
Number of Charged Particles
Generator level charged multiplicity distribution (all pT, |η
η| < 2) at 900 GeV and 7
TeV. Shows the NSD = HC + DD prediction for Tune Z1. Also shows the CMS
NSD data.
“Minumum Bias” Collisions
Proton
PIC 2011, Vancouver
August 29, 2011
Okay not perfect!
But not that bad!
Rick Field – Florida/CDF/CMS
Proton
Page 39
MB & UE
"Transverse" Charged Particle Multiplicity
Charged Multiplicity Distribution
1.0E+00
1.0E-01
“Min-Bias”
RDF Preliminary
“Underlying Event”
data CMS NSD
pyZ1 generator level
Data Corrected
Tune Z1 generator level
1.0E-01
CMS
PT(chgjet#1) > 3 GeV/c
Probability
Probability
1.0E-02
7 TeV
900 GeV
1.0E-03
1.0E-02
900 GeV
1.0E-04
0
20
CMS
Tune Z1
Tune Z1
Difficult to produce
40
60
80
enough
events
with
Number of Charged Particles
large multiplicity!
7 TeV
1.0E-03
1.0E-04
Charged Particles
(all PT, |η
η|<2.0)
CMS Preliminary
Charged Particles (|η
η|<2.0, PT>0.5 GeV/c)
1.0E-05
100
0
5
10
15
20
25
30
35
Number of Charged Particles
Difficult to produce
CMS corrected data at 900 GeV and 7
Generator level charged multiplicity
enough events with
TeV on the charged particle multiplicity
distribution (all pT, |η
η| < 2) at 900 GeV
large “transverse”
distribution in the “transverse” region for
and 7 TeV. Shows the NSD = HC + DD
multiplicity at low
η| < 2)
charged particles (pT > 0.5 GeV/c, |η
prediction for Tune Z1. Also shows the
hard scale!
as defined by the leading charged particle
CMS NSD data.
jet with PT(chgjet#1) > 3 GeV/c compared
with PYTHIA Tune Z1 at the generator
level.
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 40
How Universal are the Tunes?
Do we need a separate tune for each center-of-mass energy?
Outgoing Parton
PT(hard)
900 GeV, 1.96 TeV, 7 TeV, etc.
Initial-State Radiation
Proton
PYTHIA Tune DW did a nice (although not perfect)
job predicting the LHC Jet Production and Drell-Yan
UE data. I am still hoping for a single tune that will
describe all energies!
Proton
Underlying Event
Underlying Event
Outgoing Parton
Final-State
Radiation
Outgoing Parton
PT(hard)
Initial-State Radiation
Proton
Do we need a separate tune for each hard QCD
Proton
Underlying Event
Underlying Event
subprocess? Jet Production, Drell-Yan Production, etc.
Outgoing Parton
The same tune can describe both Jet Production and Drell-Yan!
Proton
Do we need separate tunes for “Min-Bias” (MB) and the
Final-State
Radiation
Color
“Minimum Bias” Collisions
)
P(90
R
A
P
Proton
Connections
“underlying event” (UE) in a hard scattering process?
PHTHIA Tune Z1 does fairly well at both the UE and MB,
but you cannot expect such a naïve approach to be perfect!
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Diffraction
PA
RP
(82
)
Page 41
Kaon Production
Kshort Rapidity Distribution: dN/dY
Kshort Rapidity Distribution: dN/dY
0.5
0.4
CMS
CMS Data
PYTHIA Tune Z1
0.4
CMS & ALICE Data
INEL = NSD + SD
PYTHIA Tune Z1
7 TeV
0.3
dN/dY
dN/dY
CMS NSD
0.3
0.2
900 GeV
900 GeV
0.2
0.1
0.1
ALICE INEL
Tune Z1
NSD (all pT)
0.0
pyZ1 NSD = solid
Tune Z1
pyZ1 INEL = dashed
0.0
-4
-3
-2
-1
0
1
2
3
4
-4
-3
Rapidity Y
-2
-1
0
1
2
3
Rapidity Y
CMS NSD data on the Kshort rapidity
distribution at 7 TeV and 900 GeV compared
with PYTHIA Tune Z1. The plot shows the
average number of Kshort per NSD collision per
unit Y, (1/NNSD) dN/dY.
CMS NSD data on the Kshort rapidity
distribution at 900 GeV and the ALICE point at
Y = 0 (INEL) compared with PYTHIA Tune Z1.
The ALICE point is the average number of
Kshort per INEL collision per unit Y at Y = 0,
(1/NINEL) dN/dY.
“Minimum Bias” Collisions
Kshort
Kshort
d s +d s
Proton shortage of Kaons in PYTHIA
Proton Tune Z1!
No overall
PIC 2011, Vancouver
August 29, 2011
4
Rick Field – Florida/CDF/CMS
d s +d s
Page 42
Kaon Production
Charged Kaons Rapidity: dN/dY
Rapidity Distribution Ratio: Kaons/Pions
0.3
0.6
ALICE Data
+
ALICE Data
(K +K )
dN/dY
0.4
0.2
Tune Z1
900 GeV
INEL (all pT)
+
π++π
π-)
(K +K )/(π
ALICE
PYTHIA Tune Z1
dN/dY Particle Ratio
ALICE
PYTHIA Tune Z1
-
0.2
0.1
pyZ1 NSD = dashed
pyZ1 INEL = solid
Tune Z1
900 GeV
INEL (all pT)
0.0
0.0
-4
-3
-2
-1
0
1
2
3
4
-4
-3
-2
0
1
2
3
ALICE INEL data on the charged kaon
rapidity distribution at 900 GeV compared
with PYTHIA Tune Z1. The plot shows
the average number of charged kaons per
INEL collision per unit Y at Y = 0,
(1/NINEL) dN/dY.
ALICE INEL data on the charged kaon to
charged pion rapidity ratio at 900 GeV
compared with PYTHIA Tune Z1.
(K++ K-)
(π
π++ π-)
=
Strange Meson
Non-strange Meson
“Minimum Bias” Collisions
K+
K-
Protonshortage of Kaons in PYTHIA
ProtonTune Z1!
No overall
u s
PIC 2011, Vancouver
August 29, 2011
4
Rapidity Y
Rapidity Y
u s
-1
Rick Field – Florida/CDF/CMS
Page 43
Kaon Production
Charged Kaons Rapidity: dN/dY
Rapidity Distribution Ratio: Kaons/Pions
Rapidity Distribution Ratio: Kshort/Kaons
0.3
0.8
0.6
ALICE Data
ALICE Data
ALICE
dN/dY
0.4
0.2
PYTHIA Tune Z1
ALICE Data
-
Kshort/(K++K-)
(K +K )
0.6
0.4
0.2
0.2
0.1
pyZ1 NSD = dashed
GeV
TuneINEL
Z1(all pT)
pyZ1 INEL900
= solid
900 GeV
INEL (all pT)
0.0
INEL (all pT)
-3
-2
-1
0
-4 1
-3 2
-2 3
-1 4
Rapidity Y
0
-4
1
-3 2
-2 3
-1 4
0
1
2
3
ALICE INEL data on the charged kaon to
charged pion rapidity ratio at 900 GeV
compared with PYTHIA Tune Z1.
(K++ K-)
(π
π++ π-)
=
Strange Meson
Non-strange Meson
“Minimum Bias” Collisions
K+
K-
Protonshortage of Kaons in PYTHIA
ProtonTune Z1!
No overall
u s
PIC 2011, Vancouver
August 29, 2011
4
Rapidity Y
Rapidity Y
ALICE INEL data on the charged kaon
rapidity distribution at 900 GeV compared
with PYTHIA Tune Z1. The plot shows
the average number of charged kaons per
INEL collision per unit Y at Y = 0,
(1/NINEL) dN/dY.
u s
Tune Z1
900 GeV
0.0
0.0
-4
+
π++π
π-)
(K +K )/(π
ALICE
PYTHIA Tune Z1
dN/dY Particle Ratio
dN/dY Particle Ratio
PYTHIA Tune Z1
+
Rick Field – Florida/CDF/CMS
Page 44
Particle Ratios versus PT
PT Particle Ratio: Kaons/Pions
Rapidity Distribution Ratio: Kaons/Pions
0.60
0.3
ALICE Data
(K +K )/(π
π +π
π)
+
+
-
ALICE Data
(K++K-)/(π
π++π
π-)
PYTHIA Tune Z1 & Z1C
0.40
dN/dY Particle Ratio
PT Particle Ratio
PYTHIA Tune Z1 & Z1C
-
Z1C
Z1
0.20
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
900 GeV
INEL (|Y| < 0.75)
0.2
Z1C
0.1
900 GeV
INEL (all pT)
0.00
Z1
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
0.0
0
1
2
PT (GeV/c)
3
4
-3
-2
-1
Tails of the pT distribution.
Way off due to the wrong pT!
ALICE INEL data on the charged kaons to
charged pions ratio versus pT at 900 GeV (|Y|
< 0.75) compared with PYTHIA Tune Z1 &
Z1C.(K++ K-)
Strange Meson
=
(π
π++ π-)
Non-strange Meson
0
1
2
3
K-
ALICE INEL data on the charged kaon to
charged pion rapidity ratio at 900 GeV
compared with PYTHIA Tune Z1.
PYTHIA pT dependence off onProton
Kaons!
Proton
u s
PIC 2011, Vancouver
August 29, 2011
4
Rapidity Y
“Minimum Bias” Collisions
K+
u s
-4
Rick Field – Florida/CDF/CMS
Page 45
Lambda Production
(Lam+LamBar) Rapidity Distribution: dN/dY
0.25
Rapidity Distribution Ratio: (Lam+LamBar)/(2Kshort)
0.5
_
CMS Data
(Λ
Λ+Λ
Λ)
7 TeV
PYTHIA Tune Z1
dN/dY Particle Ratio
dN/dY
0.20
0.15
0.10
900 GeV
0.05
CMS
NSD (all pT)
0.00
-4
-3
-2
-1
1
_
CMS
0.4
(Λ
Λ+Λ
Λ)/(2Kshort)
7 TeV
0.3
0.2
Factor of 1.5!
0.1
Tune Z1
NSD (all pT)
Tune Z1
0
CMS Data
PYTHIA Tune Z1
0.0
2
3
4
-4
-3
-2
Rapidity Y
-1
0
1
2
3
4
Rapidity Y
CMS NSD data on the Lambda+AntiLambda CMS NSD data on the Lambda+AntiLambda
rapidity distribution at 7 TeV and 900 GeV
to 2Kshort rapidity ratio at 7 TeV compared
compared with PYTHIA Tune Z1. The plot
with PYTHIA Tune Z1.
shows the average number of particles per
Single-strange Baryon
(Λ
Λ + Λ)
=
NSD collision per unit Y, (1/NNSD) dN/dY.
2K
short
Λ
ud s
Strange Meson
“Minimum Bias” Collisions
Proton Tune Z1!
Oops!Proton
Not enough Lambda’s in PYTHIA
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 46
Cascade Production
Rapidity Distribution Ratio: (Cas+CasBar)/(2Kshort)
(Cas+CasBar) Rapidity Distribution: dN/dY
0.03
CMS Data
−
dN/dY Particle Ratio
7 TeV
dN/dY
0.02
CMS
900 GeV
0.01
PYTHIA Tune Z1
0.04
7 TeV
0.03
Factor of 2!
0.02
0.01
Tune Z1
NSD (all pT)
Ξ −+Ξ
Ξ −)/(2Kshort)
(Ξ
CMS
CMS Data
−
(Ξ
Ξ +Ξ
Ξ )
PYTHIA Tune Z1
_
0.05
_
Tune Z1
NSD (all pT)
0.00
0.00
-4
-3
-2
-1
0
1
2
3
4
-4
-3
-2
-1
0
1
2
3
4
Rapidity Y
Rapidity Y
CMS NSD data on the Cascade CMS data on the Cascade-+AntiCascade- to
+AntiCascade- rapidity distribution at 7 TeV
2Kshort rapidity ratio at 7 TeV compared with
and 900 GeV compared with PYTHIA Tune
PYTHIA Tune Z1.
Z1. The plot shows the average number of
Double-strange Baryon
(Ξ
Ξ + Ξ)
=
particles per NSD collision per unit Y,
2Kshort
Strange Meson
(1/NNSD) dN/dY.
“Minimum Bias” Collisions
Ξ−
Proton Tune Z1!
Yikes! Proton
Way too few Cascade’s in PYTHIA
dss
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 47
Particle Ratios versus PT
Too many overall protons!
PT Particle Ratio: (P+Pbar)/Pions
Rapidity Distribution Ratio: (P+Pbar)/Pions
0.4
PYTHIA Tune Z1 & Z1C
_
(p+p)/(π
π++π
π-)
ALICE Data
PYTHIA Tune Z1 & Z1C
dN/dY Particle Ratio
PT Particle Ratio
0.12
_
π++π
π-)
(p+p)/(π
ALICE Data
0.3
Z1C
0.2
Z1
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
0.1
900 GeV
INEL (|Y| < 0.75)
Z1C
0.09
0.06
Z1
0.03
900 GeV
INEL (all pT)
0.0
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
0.00
0
1
2
PT (GeV/c)
3
4
-4
-3
Tails of the pT distribution.
Way off due to the wrong pT!
ALICE INEL data on the Proton+AntiProton
to charged pions ratio versus pT at 900 GeV
(|Y| < 0.75) compared with PYTHIA Tune Z1
Non-strange Baryon
& Z1C. (p + p)
=
(π
π++ π-)
Non-strange Meson
-2
-1
0
1
2
3
Rapidity Y
ALICE INEL data on the
Proton+AntiProton to charged pion rapidity
ratio at 900 GeV compared with PYTHIA
Tune Z1 & Z1C.
“Minimum Bias” Collisions
p
uud
PIC 2011, Vancouver
August 29, 2011
4
Proton way off on the p dependence
Protonof Protons!
PYTHIA
T
Rick Field – Florida/CDF/CMS
Page 48
Fragmentation Summary
Strange Particle & Baryon Yields: PYTHIA is off K+
Λ
Kshort
on the overall yield of Lambda’s and Cascades
u s
d s +d s
ud s
(MC below the data) and too high on the proton
p
Ξ−
K
yield. Difficult to fix this without destroying
uud
u s
dss
agreement with LEP!
PT Distributions: PYTHIA does not describe correctly the pT distributions
of heavy particles (MC softer than the data). None of the fragmentation
parameters I have looked at changes the pT distributions. Hence, if one
looks at particle ratios at large pT you can see big discrepancies between
data and MC (out in the tails of the distributions)!
Factorization: Are we seeing a breakdown in
“Minimum Bias” Collisions
+
factorization between e e annihilations and
Proton
Proton
hadron-hadron collisions! Is something
happening in hadron-hadron collisions that
does not happen in e+e- annihilations?
Herwig++ & Sherpa: Before making any conclusions about fragmentation
one must check the predictions of Herwig++ and Sherpa carefully!
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 49
Fragmentation Summary
Beam-meam remnants!
Beam-meam remnants!
ηdφ
φ
Charged Particle
dN/dη
StrangeCharged
Particle
Baryon
ηdφ
φ Yields: PYTHIA is off
Particle &
Density:
dN/dη
Λ
K+ Density:
Kshort
0.04
0.12
on RDF
thePreliminary
overall yield of Lambda’s and Cascades
RDF Preliminary u s
d s + d s(ΛΛ+ΛΛ ud s
(p+p
(MC below the data) and too high on the0.03proton
0.08
p
Ξ−
K
yield. Difficult to fix this without destroying
0.02
uud
u s
dss
agreement
with
LEP!
0.04
0.01
7 TeV ND
(all pT) not describe correctly the p
PT Distributions: PYTHIA
does
7 TeV ND (all pT)
T distributions
0.00
0.00
of-10heavy
particles
(MC
softer
than
the
data).
None
of-4 the
fragmentation
-8
-6
-4
-2
0
2
4
6
8
10
-10
-8
-6
-2
0
2
4
6
8
10
Hence,
if one
parameters I have
looked
at changes the pT distributions.
Pseudo-Rapidity
η
Pseudo-Rapidity
η
looks at particle ratios at large pT you can see big discrepancies between
data and MC (out in the tails of the distributions)!
Factorization: Are we seeing a breakdown in
“Minimum Bias” Collisions
+
factorization between e e annihilations and
Proton
Proton
hadron-hadron collisions! Is something
happening in hadron-hadron collisions that
does not happen in e+e- annihilations?
Herwig++ & Sherpa: Before making any conclusions about fragmentation
one must check the predictions of Herwig++ and Sherpa carefully!
PIC 2011, Vancouver
August 29, 2011
_
)
Charged Particle Density
Charged Particle Density
_
PYTHIA Tune Z1
PYTHIA Tune Z1
Rick Field – Florida/CDF/CMS
)
Page 50
Sherpa versus PYTHIA
Strange particle production in pp at 200 GeV
(STAR_2006_S6860818)
<pT> versus Mass
Before making any conclusion about e+eversus pp collisions one must check the
predictions of Herwig++ and Sherpa!
Sherpa does better
than PYTHIA 8!
Hendrik Hoeth
http://users.hepforge.org/~hoeth/STAR_2006_S6860818/
PIC 2011, Vancouver
August 29, 2011
Rick Field – Florida/CDF/CMS
Page 51