Early LHC Measurements
MC Tunes: What have we learned?
Rick Field
University of Florida
PARP(82)
PARP(90)
Outline of Talk
 The new ATLAS & CMS “underlying
Color
event” results.
Diffraction
Connections
 UE Summary.
Outgoing Parton
PT(hard)
 LHC “min-bias” data at 7 TeV.
Initial-State Radiation
Proton
Proton
Underlying Event
 “Min-bias” Summary.
Underlying Event
Outgoing Parton
Final-State
Radiation
UE&MB@CMS
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 1
ATLAS & CMS UE Analyses
 Uncorrected data on the “transverse”
region as defined by the leading track,
PTmax, and the leading charged particle
jet, PT(chgjet#1) at 900 GeV (pT > 0.5
GeV/c, |h| < 2.0) compared with several
QCD Monte-Carlo models after detector
simulation.
 Corrected data on the “towards”, “away”,
and “transverse” regions as defined by the
leading track, PTmax, at 7 TeV and 900 GeV
(pT > 0.5 GeV/c, |h| < 2.5) compared with
several QCD Monte-Carlo models at the
generator level.
UE&MB@CMS
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 2
ATLAS & CMS UE Analyses
Please note that I have read the
ATLAS and CMS data points
off these papers with a ruler
so that I can plot the data
and make comparisons!
Please refer to these papers
 Corrected
(not my plots)
for the data on the “towards”, “away”,
and “transverse” regions as defined by the
 Uncorrected data on the “transverse”true data points!
leading track, PTmax, at 7 TeV and 900 GeV
region as defined by the leading track,
PTmax, and the leading charged particle
jet, PT(chgjet#1) at 900 GeV (pT > 0.5
GeV/c, |h| < 2.0) compared with several
QCD Monte-Carlo models after detector
simulation.
UE&MB@CMS
UE&MB Working Group Meeting
LPCC May 31, 2010
(pT > 0.5 GeV/c, |h| < 2.5) compared with
several QCD Monte-Carlo models at the
generator level.
None of my plots are
the original figures
from the papers!
Rick Field – Florida/CDF/CMS
Page 3
“Transverse” Charged Particle Density
"Transverse" Charged Particle Density: dN/dhdf
"Transverse" Charged Density
0.8
RDF Preliminary
Fake Data
pyDW generator level
ChgJet#1
0.6
Rick Field
MB&UE@CMS Workshop
CERN, November 6, 2009
PTmax
0.4
0.2
900 GeV
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0
2
4
6
8
10
12
14
16
18
PTmax or PT(chgjet#1) (GeV/c)
 Fake data (from MC) at 900 GeV on the
“transverse” charged particle density,
dN/dhdf, as defined by the leading charged
particle (PTmax) and the leading charged
particle jet (chgjet#1) for charged particles
with pT > 0.5 GeV/c and |h| < 2. The fake
data (from PYTHIA Tune DW) are
generated at the particle level (i.e. generator
level) assuming 0.5 M min-bias events at
900 GeV (361,595 events in the plot).
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 4
“Transverse” Charged Particle Density
"Transverse" Charged Particle Density: dN/dhdf
"Transverse" Charged Particle Density: dN/dhdf
RDF Preliminary
Fake Data
pyDW generator level
"Transverse" Charged Density
"Transverse" Charged Density
0.8
ChgJet#1
0.6
PTmax
0.4
0.2
900 GeV
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.8
CMS Preliminary
ChgJet#1
data uncorrected
pyDW + SIM
0.6
PTmax
0.4
0.2
900 GeV
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0.0
0
2
4
6
8
10
12
14
16
18
0
2
6
8
10
12
14
16
18
PTmax or PT(chgjet#1) (GeV/c)
PTmax or PT(chgjet#1) (GeV/c)
 Fake data (from MC) at 900 GeV on the
“transverse” charged particle density,
dN/dhdf, as defined by the leading charged
particle (PTmax) and the leading charged
particle jet (chgjet#1) for charged particles
with pT > 0.5 GeV/c and |h| < 2. The fake
data (from PYTHIA Tune DW) are
generated at the particle level (i.e. generator
level) assuming 0.5 M min-bias events at
900 GeV (361,595 events in the plot).
UE&MB Working Group Meeting
LPCC May 31, 2010
4
 CMS preliminary data at 900 GeV on the
“transverse” charged particle density,
dN/dhdf, as defined by the leading charged
particle (PTmax) and the leading charged
particle jet (chgjet#1) for charged particles
with pT > 0.5 GeV/c and |h| < 2. The data are
uncorrected and compared with PYTHIA
Tune DW after detector simulation (216,215
events in the plot).
Rick Field – Florida/CDF/CMS
Page 5
“Transverse” Charged PTsum Density
"Transverse" Charged PTsum Density: dPT/dhdf
"Transverse" Charged PTsum Density: dPT/dhdf
0.8
0.8
ChgJet#1
Fake Data
pyDW generator level
0.6
PTsum Density (GeV/c)
PTsum Density (GeV/c)
RDF Preliminary
PTmax
0.4
0.2
900 GeV
CMS Preliminary
data uncorrected
pyDW + SIM
0.6
ChgJet#1
PTmax
0.4
0.2
900 GeV
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0.0
0
2
4
6
8
10
12
14
16
18
0
2
4
6
8
10
12
14
16
18
PTmax or PT(chgjet#1) (GeV/c)
PTmax or PT(chgjet#1) (GeV/c)
 Fake data (from MC) at 900 GeV on the
 CMS preliminary data at 900 GeV on the
“transverse” charged PTsum density,
“transverse” charged PTsum density,
dPT/dhdf, as defined by the leading charged
dPT/dhdf, as defined by the leading charged
particle (PTmax) and the leading charged
particle (PTmax) and the leading charged
particle jet (chgjet#1) for charged particles
particle jet (chgjet#1) for charged particles
with pT > 0.5 GeV/c and |h| < 2. The fake
with pT > 0.5 GeV/c and |h| < 2. The data are
data (from PYTHIA Tune DW) are generated
uncorrected and compared with PYTHIA
at the particle level (i.e. generator level)
Tune DW after detector simulation (216,215
assuming 0.5 M min-bias events at 900 GeV
events in the plot).
(361,595 events in the plot).
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 6
PYTHIA Tune CW
"Transverse" Charged PTsum Density: dPT/dhdf
0.8
0.8
CMS Preliminary
CMS Preliminary
ChgJet#1
data uncorrected
pyCW + SIM
0.6
PTsum Density (GeV/c)
"Transverse" Charged Density
"Transverse" Charged Particle Density: dN/dhdf
PTmax
0.4
0.2
900 GeV
data uncorrected
pyCW + SIM
0.6
ChgJet#1
PTmax
0.4
0.2
900 GeV
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0.0
0
2
4
6
8
10
12
14
0
2
4
6
8
10
12
PTmax or PT(chgjet#1) (GeV/c)
 CMS preliminary data at 900 GeV on the
“transverse” charged particle density,
dN/dhdf, as defined by the leading charged
particle (PTmax) and the leading charged
particle jet (chgjet#1) for charged particles
with pT > 0.5 GeV/c and |h| < 2. The data are
uncorrected and compared with PYTHIA
Tune CW after detector simulation.
 CMS preliminary data at 900 GeV on the
“transverse” charged PTsum density,
dPT/dhdf, as defined by the leading charged
particle (PTmax) and the leading charged
particle jet (chgjet#1) for charged particles
with pT > 0.5 GeV/c and |h| < 2. The data are
uncorrected and compared with PYTHIA
Tune CW after detector simulation.
Tune DW → Tune CW
PARP(82) = 1.9 → 1.8
PARP(90) = 0.25 → 0.30
PARP(85) = 1.0 → 0.9
PARP(86) = 1.0 → 0.95
UE&MB Working Group Meeting
LPCC May 31, 2010
14
PTmax or PT(chgjet#1) (GeV/c)
Rick Field – Florida/CDF/CMS
Page 7
“Transverse” Charge Density
"Transverse" Charged Particle Density: dN/dhdf
Rick Field
MB&UE@CMS Workshop
CERN, November 6, 2009
"Transverse" Charged Density
1.2
RDF Preliminary
py Tune DW generator level
7 TeV
0.8
factor of 2!
900 GeV
0.4
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0
2
4
6
8
10
12
14
16
18
20
PTmax (GeV/c)
PTmax Direction
f
LHC
900 GeV
“Toward”
“Transverse”
PTmax Direction
900 GeV → 7 TeV
(UE increase ~ factor of 2)
“Transverse”
“Away”
~0.4 → ~0.8
f
“Toward”
LHC
7 TeV
“Transverse”
“Transverse”
“Away”
 Shows the charged particle density in the “transverse” region for charged particles (pT > 0.5
GeV/c, |h| < 2) at 900 GeV and 7 TeV as defined by PTmax from PYTHIA Tune DW and at the
particle level (i.e. generator level).
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 8
“Transverse” Charge Density
"Transverse" Charged Density
"Transverse" Charged Particle Density: dN/dhdf
1.2
ATLAS Preliminary
7 TeV
data corrected
0.8
factor of 2!
900 GeV
0.4
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
0
2
4
6
8
10
12
14
16
18
20
PTmax (GeV/c)
PTmax Direction
f
LHC
900 GeV
“Toward”
“Transverse”
PTmax Direction
900 GeV → 7 TeV
(UE increase ~ factor of 2)
“Transverse”
“Away”
~0.4 → ~0.8
f
“Toward”
LHC
7 TeV
“Transverse”
“Transverse”
“Away”
 ATLAS preliminary data on the charged particle density in the “transverse” region for charged
particles (pT > 0.5 GeV/c, |h| < 2.5) at 900 GeV and 7 TeV as defined by PTmax.
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 9
“Transverse” Charge Density
PARP(90) = 0.16
"Transverse" Charged Particle Density: dN/dhdf
3.0
Ratio: 7 TeV/900 GeV
RDF Preliminary
ATLAS corrected data
generator level theory
PARP(90) = 0.25
2.0
Tune DW
1.0
ATLAS MC08
Tune CW
PARP(90) = 0.30
7 TeV / 900 GeV
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
0
1
2
3
4
5
6
7
8
9
10
11
12
PTmax (GeV/c)
PTmax Direction
f
LHC
900 GeV
“Toward”
“Transverse”
PTmax Direction
900 GeV → 7 TeV
(UE increase ~ factor of 2)
“Transverse”
“Away”
~0.4 → ~0.8
f
“Toward”
LHC
7 TeV
“Transverse”
“Transverse”
“Away”
 Ratio of the ATLAS preliminary data on the charged particle density in the “transverse” region
for charged particles (pT > 0.5 GeV/c, |h| < 2.5) at 900 GeV and 7 TeV as defined by PTmax
compared with PYTHIA Tune CW, DW, and ATLAS MC08.
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 10
PYTHIA Tune DW
"Transverse" Charged PTsum Density: dPT/dhdf
1.5
RDF Preliminary
RDF Preliminary
7 TeV
ATLAS corrected data
Tune DW generator level
PTsum Density (GeV/c)
"Transverse" Charged Density
"Transverse" Charged Particle Density: dN/dhdf
1.2
0.8
900 GeV
0.4
7 TeV
ATLAS corrected data
Tune DW generator level
1.0
900 GeV
0.5
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
0.0
0
2
4
6
8
10
12
14
16
18
20
0
2
6
8
10
12
14
16
18
PTmax (GeV/c)
PTmax (GeV/c)
 ATLAS preliminary data at 900 GeV and 7
TeV on the “transverse” charged particle
density, dN/dhdf, as defined by the leading
charged particle (PTmax) for charged
particles with pT > 0.5 GeV/c and |h| < 2.5.
The data are corrected and compared with
PYTHIA Tune DW at the generator level.
UE&MB Working Group Meeting
LPCC May 31, 2010
4
 ATLAS preliminary data at 900 GeV and 7
TeV on the “transverse” charged PTsum
density, dPT/dhdf, as defined by the leading
charged particle (PTmax) for charged
particles with pT > 0.5 GeV/c and |h| < 2.5.
The data are corrected and compared with
PYTHIA Tune DW at the generrator level.
Rick Field – Florida/CDF/CMS
Page 11
20
Tuning the Color Connections
"Transverse" Charged PTsum Density: dPT/dhdf
1.5
X18QQ
RDF Preliminary
X18GG1
f
1.0
“Toward”
“Transverse”
“Transverse”
X18GG8
0.5
“Away”
7 TeV
X18QQ
RDF Preliminary
PTmax Direction
ATLAS corrected data
generator level theory
PTsum Density (GeV/c)
"Transverse" Charged Density
"Transverse" Charged Particle Density: dN/dhdf
1.5
ATLAS corrected data
generator level theory
1.0
X18GG8
X18GG1
0.5
7 TeV
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
0.0
0
2
4
6
8
10
12
14
16
18
0
20
2
4
6
8
10
12
14
16
18
20
PTmax (GeV/c)
PTmax (GeV/c)
 Shows the charged particle and PTsum density in the “transverse” region for charged particles
(pT > 0.5 GeV/c, |h| < 2.5) at 7 TeV as defined by the leading charged particle, PTmax, for
pyX18GG8, pyX18GG1, and pyX18QQ at the particle level (i.e. generator level).
Percent of ND = HC Cross-Section
100%
5%
5%
10%
10%
Percent of HC
75%
34%
60%
60%
QQ
50%
90%
100%
33%
25%
GG1
GG8
80%
40%
40%
Tune X2
Tune X1844
33%
0%
Tune A
UE&MB Working Group Meeting
LPCC May 31, 2010
Tune
DW,D6T
Tune X1
Rick Field – Florida/CDF/CMS
ATLAS
Page 12
Tuning the Color Connections
GG8 has larger <pT>!
"Transverse" Average PT
"Transverse" Charged Average pT
1.3
Average pT (GeV/c)
X18GG8
PTmax Direction
X18QQ
generator level theory
f
1.1
“Toward”
0.9
“Transverse”
“Transverse”
X18GG1
0.7
“Away”
7 TeV
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.5
0
2
4
6
8
10
12
14
16
18
"Transverse" Average PT (GeV/c)
2.0
RDF Preliminary
CDF Run 2 Preliminary
data corrected
generator level theory
PY Tune A
1.5
1.0
"Leading Jet"
MidPoint R=0.7 |h(jet#1)|<2
HW
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.5
20
0
PTmax (GeV/c)
50
100
150
200
250
300
350
400
PT(jet#1) (GeV/c)
 Shows the charged particle average pT in the “transverse” region for charged particles (pT > 0.5
GeV/c, |h| < 2.5) at 7 TeV as defined by the leading charged particle, PTmax, for pyX18GG8,
pyX18GG1, and pyX18QQ at the particle level (i.e. generator level).
Percent of ND = HC Cross-Section
100%
5%
5%
10%
10%
Percent of HC
75%
34%
60%
60%
QQ
50%
90%
100%
33%
25%
GG1
GG8
80%
40%
40%
Tune X2
Tune X1844
Tune A has 90% GG8 and
Tune DW and D6T have
100% GG8 in order to fit
the <pT> and PTsum/Nchg
at the Tevatron!
33%
0%
Tune A
Tune
DW,D6T
Tune X1
UE&MB Working Group Meeting
LPCC May 31, 2010
ATLAS
Rick Field – Florida/CDF/CMS
Page 13
Tuning the Color Connections
GG8 has larger <pT>!
"Toward" Average PT Charged
"Transverse" Charged Average pT
1.3
1.6
X18GG8
generator level theory
CDF Run 2 Preliminary
0.9
7 TeV
2
4
6
data corrected
generator level theory
8
10
f
“Toward”
pyDW
“Transverse”
1.2
“Transverse”
X18GG1
“Away”
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.5
0
"Toward" <PT> (GeV/c)
1.1
0.7
PTmax Direction
X18QQ
0.8
12
PTmax (GeV/c)
14
16
18
"Transverse" Average PT (GeV/c)
2.0
RDF Preliminary
Average pT (GeV/c)
"Transverse" Average PT
CDF Run 2 Preliminary
data corrected
"Drell-Yan
generator Production"
level theory
1.5 70 < M(pair) < 110 GeV
pyAW
1.0
"Leading Jet"
MidPoint R=0.7 |h(jet#1)|<2
HW
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
0.5
20
ATLAS
JIM
PY Tune A
HW
0
50
100
150
200
250
300
350
400
PT(jet#1) (GeV/c)
Charged Particles (|h|<1.0, PT>0.5 GeV/c)
 Shows the charged particle average pT in the “transverse”
region
for charged particles (pT > 0.5
excluding
the lepton-pair
0.4
GeV/c, |h| < 2.5) at 7 TeV
as defined by the leading charged particle, PTmax, for pyX18GG8,
0
20
40
60
80
100
pyX18GG1, and pyX18QQ at the particle level
(i.e.
generator
level).
PT(Z-Boson) (GeV/c)
Percent of ND = HC Cross-Section
100%
5%
5%
10%
10%
Percent of HC
75%
34%
60%
60%
QQ
50%
90%
100%
33%
25%
GG1
GG8
80%
40%
40%
Tune X2
Tune X1844
Tune A has 90% GG8 and
Tune DW and D6T have
100% GG8 in order to fit
the <pT> and PTsum/Nchg
at the Tevatron!
33%
0%
Tune A
Tune
DW,D6T
Tune X1
UE&MB Working Group Meeting
LPCC May 31, 2010
ATLAS
Rick Field – Florida/CDF/CMS
Page 14
Tuning the Color Connections
GG8 has larger
PTsum/Nchg!
"Transverse" Charged Particle Ratio: PTsum/Nchg
PTmax Direction
f
“Toward”
“Transverse”
“Transverse”
“Away”
"Transverse" Ratio (GeV/c)
1.6
RDF Preliminary
X18GG8
X18QQ
ATLAS corrected data
generator level theory
1.3
1.0
0.7
X18GG1
7 TeV
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.4
0
2
4
6
8
10
12
14
16
18
20
PTmax (GeV/c)
 Shows the charged particle ratio PTsum/Nchg in the “transverse” region for charged particles
(pT > 0.5 GeV/c, |h| < 2.5) at 7 TeV as defined by the leading charged particle, PTmax, for
pyX18GG8, pyX18GG1, and pyX18QQ at the particle level (i.e. generator level).
Percent of ND = HC Cross-Section
100%
5%
5%
10%
10%
Percent of HC
75%
34%
60%
60%
QQ
50%
90%
100%
33%
25%
GG1
GG8
80%
40%
40%
Tune X2
Tune X1844
33%
0%
Tune A
UE&MB Working Group Meeting
LPCC May 31, 2010
Tune
DW,D6T
Tune X1
ATLAS
Rick Field – Florida/CDF/CMS
Page 15
PYTHIA Tune X1
"Transverse" Charged PTsum Density: dPT/dhdf
1.5
RDF Preliminary
RDF Preliminary
7 TeV
ATLAS corrected data
Tune X1 generator level
PTsum Density (GeV/c)
"Transverse" Charged Density
"Transverse" Charged Particle Density: dN/dhdf
1.2
0.8
900 GeV
0.4
7 TeV
ATLAS corrected data
Tune X1 generator level
1.0
900 GeV
0.5
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
0.0
0
2
4
6
8
10
12
14
16
18
20
0
2
PTmax (GeV/c)
4
6
8
10
12
14
16
18
PTmax (GeV/c)
 ATLAS preliminary data at 900 GeV and 7
TeV on the “transverse” charged particle
density, dN/dhdf, as defined by the leading
charged particle (PTmax) for charged
particles with pT > 0.5 GeV/c and |h| < 2.5.
The data are corrected and compared with
PYTHIA Tune X1 at the generator level.
 ATLAS preliminary data at 900 GeV and 7
TeV on the “transverse” charged PTsum
density, dPT/dhdf, as defined by the leading
charged particle (PTmax) for charged
particles with pT > 0.5 GeV/c and |h| < 2.5.
The data are corrected and compared with
PYTHIA Tune X1 at the generrator level.
Tune DW → Tune X1
PARP(82) = 1.9 → 1.8
PARP(85) = 1.0 → 0.8
PARP(86) = 1.0 → 0.9
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 16
20
PYTHIA Tune X1
"Transverse" Charged PTsum Density: dPT/dhdf
"Transverse" Charged Particle Density: dN/dhdf
4.0
4.0
RDF Preliminary
3.0
Ratio: 7 TeV/900 GeV
Ratio: 7 TeV/900 GeV
RDF Preliminary
ATLAS corrected data
Tune X1 generator level
2.0
1.0
ATLAS corrected data
Tune X1 generator level
3.0
2.0
1.0
7 TeV / 900 GeV
7 TeV / 900 GeV
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
0.0
0
1
2
3
4
5
6
7
8
9
10
11
12
0
1
2
3
4
5
6
7
8
9
10
11
PTmax (GeV/c)
PTmax (GeV/c)
 Ratio of the ATLAS preliminary data on the
charged particle density in the “transverse”
region for charged particles (pT > 0.5 GeV/c,
|h| < 2.5) at 900 GeV and 7 TeV as defined by
PTmax compared with PYTHIA Tune X1 at
the generator level.
 Ratio of the ATLAS preliminary data on the
charged PTsum density in the “transverse”
region for charged particles (pT > 0.5 GeV/c,
|h| < 2.5) at 900 GeV and 7 TeV as defined by
PTmax compared with PYTHIA Tune X1 at
the generator level.
Tune DW → Tune X1
PARP(82) = 1.9 → 1.8
PARP(85) = 1.0 → 0.8
PARP(86) = 1.0 → 0.9
UE&MB Working Group Meeting
LPCC May 31, 2010
12
Rick Field – Florida/CDF/CMS
Page 17
PYTHIA Tune X1
"Transverse" Charged Particle Density:
dN/dhdfCharged
"Transverse"
2.0
1.0
7 TeV / 900 GeV
0.0
0
1
2
3
4
"Transverse" Ratio (GeV/c)
Ratio: 7 TeV/900 GeV
3.0
RDF Preliminary
1.6
RDF Preliminary
ATLAS corrected data
Tune X1 generator level
5
RDF Preliminary
1.3
Ratio: 7 TeV/900 GeV
4.0
"Transverse" Charged PTsum Density: dPT/dhdf
Particle
Ratio: PTsum/Nchg
4.0
ATLAS corrected data
Tune X1 generator level
1.0
ATLAS corrected data
Tune X1 generator level
3.0
2.0
1.0
7 TeV / 900 GeV
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
0.7
6
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
7
8
9
7 TeV
10
11
0
12
1
2
3
4
5
6
7
8
9
10
11
12
Charged Particles (|h|<2.5, PT>0.5
GeV/c)
PTmax
(GeV/c)
PTmax (GeV/c)
0.4
0
2 data
4 on 6the
 Ratio of the ATLAS preliminary
charged particle density in the “transverse”
region for charged particles (pT > 0.5 GeV/c,
|h| < 2.5) at 900 GeV and 7 TeV as defined by
PTmax compared with PYTHIA Tune X1 at
the generator level.
10
12
16
18
20
 Ratio
of the14ATLAS
preliminary
data on the
PTmaxcharged
(GeV/c) PTsum density in the “transverse”
region for charged particles (pT > 0.5 GeV/c,
|h| < 2.5) at 900 GeV and 7 TeV as defined by
PTmax compared with PYTHIA Tune X1 at
the generator level.
8
Tune DW → TuneX1
PARP(82) = 1.9 → 1.8
PARP(85) = 1.0 → 0.8
PARP(86) = 1.0 → 0.9
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 18
CDF Run 2 Min-Bias “Associated”
Charged Particle Density
PY Tune A
PTmax > 2.0 GeV/c
PTmax Direction
Direction
PTmax
f
“Toward”
“Transverse”
“Transverse”
Correlations in f
“Away”
PTmax > 2.0 GeV/c
Associated Particle Density
f
Associated Particle Density: dN/dhdf
1.0
CDF Preliminary
PY Tune A
0.8
data uncorrected
theory + CDFSIM
PTmax > 0.5 GeV/c
PY Tune A
Transverse
Region
0.6
PY Tune A 1.96 TeV
Transverse
Region
0.4
0.2
PTmax
PTmax not included
(|h|<1.0, PT>0.5 GeV/c)
0.0
0
30
60
90
120
PTmax > 0.5 GeV/c
150
180
210
240
270
300
330
360
f (degrees)
 Shows the data on the f dependence of the “associated” charged particle density,
dNchg/dhdf, for charged particles (pT > 0.5 GeV/c, |h| < 1, not including PTmax) relative
to PTmax (rotated to 180o) for “min-bias” events with PTmax > 0.5 GeV/c and PTmax >
2.0 GeV/c compared with PYTHIA Tune A (after CDFSIM).
 PYTHIA Tune A predicts a larger correlation than is seen in the “min-bias” data (i.e.
Tune A “min-bias” is a bit too “jetty”).
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 19
CDF Run 2 Min-Bias “Associated”
Charged Particle Density
PY Tune A
PTmax > 2.0 GeV/c
PTmax Direction
Direction
PTmax
f
PTmax > 2.0 GeV/c
Associated Particle Density
f
Associated Particle Density: dN/dhdf
1.0
CDF Preliminary
PY Tune A
0.8
data uncorrected
theory + CDFSIM
PTmax > 0.5 GeV/c
PY Tune A
Transverse
Region
The problem in fitting the “toward”
associated
particle density seen
0.4
“Transverse”
“Transverse”
10 years 0.2
ago at CDF also appears
Correlations in f
“Away”
at 900 GeV
and 7 TeV inPTmax
PTmax not included
0.0
the ATLAS
&60 CMS
data!
0
30
90
120 150 180 210
“Toward”
0.6
PTmax > 0.5 GeV/c
PY Tune A 1.96 TeV
Transverse
Region
(|h|<1.0, PT>0.5 GeV/c)
240
270
300
330
360
f (degrees)
 Shows the data on the f dependence of the “associated” charged particle density,
dNchg/dhdf, for charged particles (pT > 0.5 GeV/c, |h| < 1, not including PTmax) relative
to PTmax (rotated to 180o) for “min-bias” events with PTmax > 0.5 GeV/c and PTmax >
2.0 GeV/c compared with PYTHIA Tune A (after CDFSIM).
 PYTHIA Tune A predicts a larger correlation than is seen in the “min-bias” data (i.e.
Tune A “min-bias” is a bit too “jetty”).
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 20
UE Summary
The “underlying event” at 7 TeV
and 900 GeV is almost what we
expected! I expect that a PYTHIA
6 tune just slightly different than
Tune DW will fit the UE data
perfectly including the energy
dependence (Tune X1 is not bad!).
I also expect to see good PYTHIA 8
tune soon!
Outgoing Parton
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
“Min-Bias” is a whole different story!
Much more complicated due to
diffraction!
I will quickly show you some of my
attempts (all failures) to fit the LHC
“min-bias” data.
UE&MB Working Group Meeting
LPCC May 31, 2010
Underlying Event
Rick Field – Florida/CDF/CMS
Final-State
Radiation
PARP(82)
PARP(90)
Color
Diffraction
Connections
Page 21
<PT> versus Nchg
Average PT versus Nchg
Average PT versus Nchg
1.4
1.4
data corrected
generator level theory
1.2
CDF Run 2 Published
pyA
pyDW
Average PT (GeV/c)
Average PT (GeV/c)
CDF Run 2 Published
1.0
ATLAS
0.8
data corrected
generator level theory
1.2
CDF Published Data
pyX18GG8 Run2
pyX18GG1 Run2
pyX18QQ Run2
ND 1.96 TeV
1.0
0.8
ND 1.96 TeV
Charged Particles (|h|<1.0, PT>0.4 GeV/c)
Charged Particles (|h|<1.0, PT>0.4 GeV/c)
0.6
0.6
0
5
10
15
20
25
30
35
40
45
0
5
10
15
20
25
30
35
40
45
Number of Charged Particles
Number of Charged Particles
 Shows how changing the color connections
 CDF ND data on the <pT> versus Nchg
compared with Tune A(ND), Tune DW(ND) and affects the <pT> versus Nchg . Here the data and
theory are non-diffractive (ND). Here you can
Tune ATLAS MC08(ND). This is why no one
understand why Tune DW rises faster than the
likes the ATLAS MC08 Tune!
data and why the ATLAS tunes does so poorly.
Percent of ND = HC Cross-Section
100%
5%
5%
10%
10%
75%
Percent of HC
The CDF “min-bias” data are
telling us that the correct tune
must be largely GG8!
Okay Tune A and DW have
a little to much GG8!
34%
60%
60%
QQ
50%
90%
100%
33%
25%
GG1
GG8
80%
40%
40%
Tune X2
Tune X1844
33%
0%
Tune A
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Tune
DW,D6T
Tune X1
ATLAS
Page 22
<PT> versus Nchg
Average PT versus Nchg
data corrected
generator level theory
1.2
1.0
0.8
1.2
CDF Run 2 Published
data corrected
generator level theory
ATLAS
1.0
CDF Published Data
pyX18GG8 Run2
pyX18GG1 Run2
Published
DataRun2
pyX18QQ
CDF Run 2 Published
pyA
Average PT (GeV/c)
1.4
pyDW
Average PT (GeV/c)
Average PT (GeV/c)
CDF Run 2 Published
Average PT versus Nchg
Average PT versus
Nchg
1.4
1.4
data corrected
generator level theory
CDF
1.2
ND 1.96 TeVpyX188090
80% GG8
10% GG11.0
10% QQ
0.8
ND 1.96 TeV
Tune X1!
Charged Particles (|h|<1.0, PT>0.4 GeV/c)
Charged Particles (|h|<1.0, PT>0.4 GeV/c)
0.6
0
5
10
15
20
0.6
25
30
35
40
0.8 Particles
Number of Charged
45
0
5
10
ND 1.96 TeV
15
20
25
30
35
40
45
Number of Charged Particles
 Shows how changing the color connections
 CDF ND data on the <pT> versus Nchg
Charged Particles (|h|<1.0, PT>0.4 GeV/c)
0.6
compared with Tune A(ND),
Tune DW(ND) and affects the <pT> versus Nchg . Here the data and
0
5
10
15
20
25 are non-diffractive
30
35
40 (ND).
45
theory
Here you can
Tune ATLAS MC08(ND). This is why no one
Number ofunderstand
Charged Particles
why Tune DW rises faster than the
likes the ATLAS MC08 Tune!
data and why the ATLAS tunes does so poorly.
Percent of ND = HC Cross-Section
100%
5%
5%
10%
10%
75%
Percent of HC
The CDF “min-bias” data are
telling us that the correct tune
must be largely GG8!
Okay Tune A and DW have
a little to much GG8!
34%
60%
60%
QQ
50%
90%
100%
33%
25%
GG1
GG8
80%
40%
40%
Tune X2
Tune X1844
33%
0%
Tune A
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Tune
DW,D6T
Tune X1
ATLAS
Page 23
PYTHIA Tune X2
Percent of INEL Cross-Section
11.2%
8.0%
12.9%
15.3%
Percent INEL
75%
22.3%
100%
9.2%
19.2%
DD
SD
66.5%
9.4%
85.6%
90.6%
PY 900
ALICE 900
15.9%
10.4%
75%
50%
76.7%
14.4%
13.2%
78.3%
67.9%
25%
HC
Percent NSD
100%
Percent of NSD Cross-Section
DD
50%
84.1%
89.0%
25%
0%
0%
PY 900
ALICE 900
PY 7 TEV
Tune X3 7 TeV
PY 7 TEV
Tune X3 7 TeV
 For Tune X2 I will attempt to produce enough charged particles (all pT) at 7 TeV
(i.e. fit the CMS NSD dN/dh distribution). It is important to have a tune that gets
the average multiplicity right! I will only look at 7 TeV “min-bias” data. Tune X2
does fit the “underlying event” data!
 Tune X2 uses the PYTHIA HC, SD, DD fractions for INEL (above left) and HC, DD
fractions for NSD (above right). PYTHIA is thought to predict to much SD and DD.
Tune X3 (not ready yet) will use the ALICE DD and SD fractions (see above). For
now I will try and do the best possible using the PYTHIA SD and DD fractions.
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 24
HC
Color Connections
7 TeV
Average Number of Charged Particles
120
104.8
83.9
88.4
70.3
66.4 68.3
60
40
14.1 14.1 14.1
20
PARP(82)=1.7
34.0
30
25
PARP(82)=1.8
36.4
35
PARP(82)=1.6
Average Nchg
Average Nchg
39.1
40
PARP(82)=1.7
93.2
79.9
80
All pT |h|<2
45
PARP(82)=1.8
98.8
100
7 TeV
Average Number of Charged Particles
All pT All h
27.7
29.4
31.3
PARP(82)=1.6
CMS
21.9
20.5 21.2
20
15
10
17.0 17.0 17.0
3.0
5
3.0
3.0
3.0
3.0
3.0
0
0
GG8
GG1
QQbar
SD
GG8
DD
GG1
QQbar
SD
DD
 Shows how changing the color connections affects the average number of charged particles.
Also shows the SD and ND contributions. CMS sees about ~24 charged particles (all pT, |h| <
2).
Percent of ND = HC Cross-Section
100%
5%
5%
10%
10%
Percent of HC
75%
34%
60%
60%
QQ
50%
90%
100%
33%
25%
GG1
GG8
80%
40%
40%
Tune X2
Tune X1844
33%
0%
Tune A
UE&MB Working Group Meeting
LPCC May 31, 2010
Tune
DW,D6T
Tune X1
ATLAS
Rick Field – Florida/CDF/CMS
Page 25
Color Connections
Charged Particle Density: dN/dh
pyATLAS is equal
mixtures of all three!
Charged Particle Density
12
10
DW, DWT, and D6T
are 100% GG8!
RDF Preliminary
data CMS NSD
generator level theory
8
6
4
2
CMS NSD 7 TeV
7 TeV
pyX18GG1 HC (8.2)
Charged Particles (all PT)
pyX18QQ HC (6.7)
pyX18GG8 HC (4.9)
0
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
PseudoRapidity h
 Generator level dN/dh (all pT). Shows the HC contribution for the three color
connections GG8, GG1, and QQbar. Also shows the CMS NSD data.
Percent of ND = HC Cross-Section
100%
5%
5%
10%
10%
Percent of HC
75%
34%
60%
60%
QQ
50%
90%
100%
33%
25%
GG1
GG8
80%
40%
40%
Tune X2
Tune X1844
33%
0%
Tune A
UE&MB Working Group Meeting
LPCC May 31, 2010
Tune
DW,D6T
Tune X1
ATLAS
Rick Field – Florida/CDF/CMS
Page 26
PYTHIA Tune X2
Charged Particle Density: dN/dh
12
CMS NSD 7 TeV
Charged Particle Density
RDF Preliminary
10
pyX2 HC (6.87)
data CMS NSD
generator level theory
60% GG1
40% GG8
pyX2 NSD (5.91)
pyDD (0.7)
8
6
4
7 TeV
2
Charged Particles (all PT)
0
-3.0
-2.5
-2.0
-1.5
-1.0
84% HC
16% DD
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
PseudoRapidity h
 Generator level dN/dh (all pT). Shows the NSD = HC + DD, HC = ND, and DD
contributions for Tune X2. Also shows the CMS NSD data.
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 27
PYTHIA Tune X2
Charged Particle Density: dN/dh
Charged Particle Density
8
RDF Preliminary
CMS NSD all pT
6
4
2
ATLAS INEL pT > 0.5 GeV/c Nchg ≥ 1
Tune X2 7 TeV
0
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
PseudoRapidity h
SD = 9.4%, DD = 6.8%!
 Shows the CMS NSD data for dN/dh (all pT) and the ATLAS INEL data for dN/dh
(pT > 0.5 GeV/c, Nchg ≥ 1) compared with Tune X2 (generator level).
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 28
Color Connections
7 TeV
All pT All h
7 TeV
Average Charged Particle PT
All pT |h| < 2
0.70
0.70
PARP(82)=1.8
0.64
0.62 0.63
PARP(82)=1.7
PARP(82)=1.6
0.54
0.53 0.54
0.48 0.48 0.48
0.50
0.44 0.44 0.43
0.40
0.33 0.33 0.33
0.34 0.34 0.34
0.30
PARP(82)=1.8
PARP(82)=1.7
0.60
Average PT (GeV/c)
Average PT (GeV/c)
0.60
Average Charged Particle PT
PARP(82)=1.6
0.53 0.52 0.52
0.50
CMS
0.47 0.47 0.46
0.40
0.36 0.36 0.36
0.36 0.36 0.36
SD
DD
0.30
0.20
0.20
GG8
GG1
QQbar
SD
DD
GG8
GG1
QQbar
 Shows how changing the color connections affects the average transverse momentum of
charged particles. Also shows the SD and ND contributions. CMS sees <pT> ~ 0.545 GeV/c
(all pT, |h| < 2).
Tune X2 gives the right average
number of charged particles but <pT> = 0.501
is a long way off on the the
observed average pT (i.e. too small)!
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 29
PYTHIA Tune X2
Average PT versus Nchg
1.4
Average PT (GeV/c)
RDF Preliminary
ATLAS INEL data
generator level theory
1.2
1.0
0.8
Tune X2
7 TeV INEL
pT > 0.5 GeV/c |h| < 2.5
0.6
0
10
20
30
40
50
60
70
80
90
Number of Charged Particles
 Shows the CMS NSD data for <pT> versus Nchg (all pT) and the ATLAS INEL data
for <pT> versus Nchg (pT > 0.5 GeV/c, Nchg ≥ 1) compared with Tune X2 (generator
level).
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 30
Color Connections
Average PT versus Nchg
Average PT versus Nchg
1.4
1.4
1.0
Average PT (GeV/c)
Average PT (GeV/c)
Tune X1844
ATLAS INEL data
generator level theory
ATLAS INEL data
generator level theory
1.2
RDF Preliminary
pyX18GG8
RDF Preliminary
pyX18QQ
pyX18GG1
0.8
1.2
1.0
Gives the right <pT>!
0.8
pT > 0.5 GeV/c |h| < 2.5
7 TeV INEL
pT > 0.5 GeV/c |h| < 2.5
7 TeV
0.6
0.6
0
10
20
30
40
50
60
70
80
0
90
10
20
30
40
50
60
70
80
Number of Charged Particles
Number of Charged Particles
 Shows the ATLAS INEL data for <pT> versus Nchg (pT > 0.5 GeV/c, Nchg ≥ 1)
compared with Tune X18GG8, X18GG1, and X18QQ (left) and PYTHIA Tune
X1844 (INEL, right).
Percent of ND = HC Cross-Section
100%
5%
5%
10%
10%
Percent of HC
75%
34%
60%
60%
QQ
50%
100%
90%
33%
25%
GG1
GG8
80%
40%
40%
Tune X2
Tune X1844
33%
0%
Tune A
UE&MB Working Group Meeting
LPCC May 31, 2010
Tune
DW,D6T
Tune X1
ATLAS
Rick Field – Florida/CDF/CMS
Page 31
90
Color Connections
Charged Particle Density: dN/dhAverage PT versus Nchg
Average PT versus Nchg
1.4
7 TeV
0.6
0
10
20
30
6
pyX18QQ
4
pyX18GG1
1.2
1.0
Tune X1844
0.8
pT > 0.5 GeV/c |h| < 2.5
7 TeV INEL
pT > 0.5 GeV/c |h| < 2.5
2
40
Tune X1844
ATLAS INEL data
Tune generator
X2
level CMS
theory NSD all pT
Average PT (GeV/c)
0.8
Charged Particle Density
Average PT (GeV/c)
1.0
RDF Preliminary
pyX18GG8
CMS Preliminary
ATLAS INEL data
generator level theory
1.2
1.4
8
RDF Preliminary
0.6
50
60
Number of Charged Particles
70
80
0
90
10
20
7 TeV NSD All pT
30
40
50
60
70
80
Number of Charged Particles
0
-3.0
-2.5 -2.0 -1.5 -1.0 -0.5 0.0
0.5
1.0
1.5
2.5
3.0
 Shows the ATLAS INEL data
for <pT> versus Nchg
(pT
>
0.52.0GeV/c,
Nchg ≥ 1)
PseudoRapidity h
compared with Tune X18GG8, X18GG1, and X18QQ (left) and PYTHIA Tune
X1844 (INEL, right).
Percent of ND = HC Cross-Section
100%
5%
5%
10%
10%
Percent of HC
75%
34%
60%
60%
QQ
50%
100%
90%
33%
25%
GG1
GG8
80%
40%
40%
Tune X2
Tune X1844
33%
0%
Tune A
UE&MB Working Group Meeting
LPCC May 31, 2010
Tune
DW,D6T
Tune X1
ATLAS
Rick Field – Florida/CDF/CMS
Page 32
90
Min-Bias Summary
We are learning a lot about how nature works!
We are a long way from having a model that will fit all the features of the
LHC min-bias data!
I think the problem is that we do not understand diffraction well enough
yet!
Color
Diffraction
Connections
UE&MB Working Group Meeting
LPCC May 31, 2010
Rick Field – Florida/CDF/CMS
Page 33