UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 1
Early LHC MeasurementsEarly LHC Measurements
Rick FieldUniversity of Florida
Outline of Talk
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation “Min-bias” Summary.
UE Summary.
LHC “min-bias” data at 7 TeV.
UE&MB@CMSUE&MB@CMS
MC Tunes: What have we learned?
The new ATLAS & CMS “underlying event” results.
PARP(90)
Color
Connections
PARP(82)
Diffraction
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 2
ATLAS & CMS UE AnalysesATLAS & 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, || < 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, || < 2.5) compared with several QCD Monte-Carlo models at the generator level.
UE&MB@CMSUE&MB@CMS
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 3
ATLAS & CMS UE AnalysesATLAS & 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, || < 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, || < 2.5) compared with several QCD Monte-Carlo models at the generator level.
UE&MB@CMSUE&MB@CMS
Please note that I have read the ATLAS and CMS data pointsoff these papers with a ruler
so that I can plot the dataand make comparisons!
Please refer to these papers(not my plots) for the
true data points!
None of my plots are the original figures from the papers!
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 4
““Transverse” Charged Particle DensityTransverse” Charged Particle Density
Fake data (from MC) at 900 GeV on the “transverse” charged particle density, dN/dd, 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 || < 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).
"Transverse" Charged Particle Density: dN/dd
0.0
0.2
0.4
0.6
0.8
0 2 4 6 8 10 12 14 16 18
PTmax or PT(chgjet#1) (GeV/c)
"Tra
ns
vers
e"
Ch
arg
ed D
ensi
ty
900 GeV
Charged Particles (||<2.0, PT>0.5 GeV/c)
RDF PreliminaryFake Data
pyDW generator levelChgJet#1
PTmax Rick FieldMB&UE@CMS WorkshopCERN, November 6, 2009
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 5
““Transverse” Charged Particle DensityTransverse” Charged Particle Density
Fake data (from MC) at 900 GeV on the “transverse” charged particle density, dN/dd, 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 || < 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).
"Transverse" Charged Particle Density: dN/dd
0.0
0.2
0.4
0.6
0.8
0 2 4 6 8 10 12 14 16 18
PTmax or PT(chgjet#1) (GeV/c)
"Tra
ns
vers
e"
Ch
arg
ed D
ensi
ty
900 GeV
Charged Particles (||<2.0, PT>0.5 GeV/c)
RDF PreliminaryFake Data
pyDW generator levelChgJet#1
PTmax
CMS preliminary data at 900 GeV on the “transverse” charged particle density, dN/dd, 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 || < 2. The data are uncorrected and compared with PYTHIA Tune DW after detector simulation (216,215 events in the plot).
"Transverse" Charged Particle Density: dN/dd
0.0
0.2
0.4
0.6
0.8
0 2 4 6 8 10 12 14 16 18
PTmax or PT(chgjet#1) (GeV/c)
"Tra
nsv
erse
" C
har
ged
Den
sity CMS Preliminary
data uncorrectedpyDW + SIM
900 GeV
ChgJet#1
PTmax
Charged Particles (||<2.0, PT>0.5 GeV/c)
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 6
““Transverse” Charged PTsum DensityTransverse” Charged PTsum Density
"Transverse" Charged PTsum Density: dPT/dd
0.0
0.2
0.4
0.6
0.8
0 2 4 6 8 10 12 14 16 18
PTmax or PT(chgjet#1) (GeV/c)
PT
su
m D
en
sity
(G
eV
/c)
900 GeV
Charged Particles (||<2.0, PT>0.5 GeV/c)
ChgJet#1
PTmax
RDF PreliminaryFake Data
pyDW generator level
Fake data (from MC) at 900 GeV on the “transverse” charged PTsum density, dPT/dd, 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 || < 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).
"Transverse" Charged PTsum Density: dPT/dd
0.0
0.2
0.4
0.6
0.8
0 2 4 6 8 10 12 14 16 18
PTmax or PT(chgjet#1) (GeV/c)
PT
sum
Den
sity
(G
eV/c
)
CMS Preliminarydata uncorrected
pyDW + SIM
900 GeV
Charged Particles (||<2.0, PT>0.5 GeV/c)
ChgJet#1
PTmax
CMS preliminary data at 900 GeV on the “transverse” charged PTsum density, dPT/dd, 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 || < 2. The data are uncorrected and compared with PYTHIA Tune DW after detector simulation (216,215 events in the plot).
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 7
PYTHIA Tune CWPYTHIA Tune CW
CMS preliminary data at 900 GeV on the “transverse” charged PTsum density, dPT/dd, 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 || < 2. The data are uncorrected and compared with PYTHIA Tune CW after detector simulation.
"Transverse" Charged Particle Density: dN/dd
0.0
0.2
0.4
0.6
0.8
0 2 4 6 8 10 12 14
PTmax or PT(chgjet#1) (GeV/c)
"Tra
nsv
erse
" C
har
ged
Den
sity CMS Preliminary
data uncorrectedpyCW + SIM
900 GeV
Charged Particles (||<2.0, PT>0.5 GeV/c)
ChgJet#1
PTmax
"Transverse" Charged PTsum Density: dPT/dd
0.0
0.2
0.4
0.6
0.8
0 2 4 6 8 10 12 14
PTmax or PT(chgjet#1) (GeV/c)
PT
sum
Den
sity
(G
eV/c
)
CMS Preliminarydata uncorrected
pyCW + SIM
900 GeV
Charged Particles (||<2.0, PT>0.5 GeV/c)
ChgJet#1
PTmax
CMS preliminary data at 900 GeV on the “transverse” charged particle density, dN/dd, 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 || < 2. The data are uncorrected and compared with PYTHIA Tune CW after detector simulation.
Tune DW → Tune CWPARP(82) = 1.9 → 1.8
PARP(90) = 0.25 → 0.30PARP(85) = 1.0 → 0.9
PARP(86) = 1.0 → 0.95
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 8
““Transverse” Charge DensityTransverse” Charge Density
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
LHC 900 GeV
LHC7 TeV
900 GeV → 7 TeV (UE increase ~ factor of 2)
"Transverse" Charged Particle Density: dN/dd
0.0
0.4
0.8
1.2
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
"Tra
ns
ve
rse
" C
ha
rge
d D
en
sit
y
Charged Particles (||<2.0, PT>0.5 GeV/c)
RDF Preliminarypy Tune DW generator level
900 GeV
7 TeV
Shows the charged particle density in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 2) at 900 GeV and 7 TeV as defined by PTmax from PYTHIA Tune DW and at the particle level (i.e. generator level).
factor of 2!
~0.4 → ~0.8
Rick FieldMB&UE@CMS WorkshopCERN, November 6, 2009
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 9
"Transverse" Charged Particle Density: dN/dd
0.0
0.4
0.8
1.2
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
"Tra
nsv
erse
" C
har
ged
Den
sity ATLAS Preliminary
data corrected
900 GeV
7 TeV
Charged Particles (||<2.5, PT>0.5 GeV/c)
““Transverse” Charge DensityTransverse” Charge Density
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
LHC 900 GeV
LHC7 TeV
900 GeV → 7 TeV (UE increase ~ factor of 2)
ATLAS preliminary data on the charged particle density in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 2.5) at 900 GeV and 7 TeV as defined by PTmax.
factor of 2!
~0.4 → ~0.8
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 10
““Transverse” Charge DensityTransverse” Charge Density
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
LHC 900 GeV
LHC7 TeV
900 GeV → 7 TeV (UE increase ~ factor of 2)
Ratio of the ATLAS preliminary data on the charged particle density in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 2.5) at 900 GeV and 7 TeV as defined by PTmax compared with PYTHIA Tune CW, DW, and ATLAS MC08.
~0.4 → ~0.8
PARP(90) = 0.16
PARP(90) = 0.25
PARP(90) = 0.30
"Transverse" Charged Particle Density: dN/dd
0.0
1.0
2.0
3.0
0 1 2 3 4 5 6 7 8 9 10 11 12
PTmax (GeV/c)
Rat
io:
7 T
eV/9
00 G
eV
Charged Particles (||<2.5, PT>0.5 GeV/c)
RDF PreliminaryATLAS corrected datagenerator level theory
7 TeV / 900 GeV
Tune DWATLAS MC08
Tune CW
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 11
PYTHIA Tune DWPYTHIA Tune DW
ATLAS preliminary data at 900 GeV and 7 TeV on the “transverse” charged PTsum density, dPT/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 2.5. The data are corrected and compared with PYTHIA Tune DW at the generrator level.
ATLAS preliminary data at 900 GeV and 7 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 2.5. The data are corrected and compared with PYTHIA Tune DW at the generator level.
"Transverse" Charged Particle Density: dN/dd
0.0
0.4
0.8
1.2
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
"Tra
nsv
erse
" C
har
ged
Den
sity RDF Preliminary
ATLAS corrected dataTune DW generator level
900 GeV
7 TeV
Charged Particles (||<2.5, PT>0.5 GeV/c)
"Transverse" Charged PTsum Density: dPT/dd
0.0
0.5
1.0
1.5
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
PT
sum
Den
sity
(G
eV/c
)
RDF PreliminaryATLAS corrected data
Tune DW generator level
900 GeV
7 TeV
Charged Particles (||<2.5, PT>0.5 GeV/c)
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 12
Tuning the Color ConnectionsTuning the Color Connections
Shows the charged particle and PTsum density in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 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).
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
"Transverse" Charged Particle Density: dN/dd
0.0
0.5
1.0
1.5
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
"Tra
nsv
erse
" C
har
ged
Den
sity RDF Preliminary
ATLAS corrected datagenerator level theory
7 TeVCharged Particles (||<2.5, PT>0.5 GeV/c)
X18GG8
X18GG1X18QQ
"Transverse" Charged PTsum Density: dPT/dd
0.0
0.5
1.0
1.5
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
PT
sum
Den
sity
(G
eV/c
)
RDF PreliminaryATLAS corrected datagenerator level theory
7 TeVCharged Particles (||<2.5, PT>0.5 GeV/c)
X18GG8 X18GG1
X18QQ
Percent of ND = HC Cross-Section
90%100%
80%
40% 40%33%
5%10%
60%
33%
5% 10%
60%
34%
0%
25%
50%
75%
100%
Tune A TuneDW,D6T
Tune X1 Tune X2 Tune X1844 ATLAS
Per
cen
t o
f H
C
GG1
GG8
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 13
Tuning the Color ConnectionsTuning the Color Connections
Shows the charged particle average pT in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 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).
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
"Transverse" Charged Average pT
0.5
0.7
0.9
1.1
1.3
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
Ave
rag
e p
T (
GeV
/c)
RDF Preliminarygenerator level theory
7 TeVCharged Particles (||<2.5, PT>0.5 GeV/c)
X18GG8
X18GG1
X18QQ
Tune A has 90% GG8 and Tune DW and D6T have100% GG8 in order to fit
the <pT> and PTsum/Nchgat the Tevatron!
"Transverse" Average PT
0.5
1.0
1.5
2.0
0 50 100 150 200 250 300 350 400
PT(jet#1) (GeV/c)
"Tra
ns
vers
e" A
ver
age
PT
(G
eV
/c) CDF Run 2 Preliminary
data correctedgenerator level theory
"Leading Jet"MidPoint R=0.7 |(jet#1)|<2
Charged Particles (||<1.0, PT>0.5 GeV/c)
PY Tune A
HW
Percent of ND = HC Cross-Section
90%100%
80%
40% 40%33%
5%10%
60%
33%
5% 10%
60%
34%
0%
25%
50%
75%
100%
Tune A TuneDW,D6T
Tune X1 Tune X2 Tune X1844 ATLAS
Per
cen
t o
f H
C
GG1
GG8
GG8 has larger <pT>!
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 14
Tuning the Color ConnectionsTuning the Color Connections
Shows the charged particle average pT in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 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).
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
"Transverse" Charged Average pT
0.5
0.7
0.9
1.1
1.3
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
Ave
rag
e p
T (
GeV
/c)
RDF Preliminarygenerator level theory
7 TeVCharged Particles (||<2.5, PT>0.5 GeV/c)
X18GG8
X18GG1
X18QQ
Tune A has 90% GG8 and Tune DW and D6T have100% GG8 in order to fit
the <pT> and PTsum/Nchgat the Tevatron!
"Transverse" Average PT
0.5
1.0
1.5
2.0
0 50 100 150 200 250 300 350 400
PT(jet#1) (GeV/c)
"Tra
ns
vers
e" A
ver
age
PT
(G
eV
/c) CDF Run 2 Preliminary
data correctedgenerator level theory
"Leading Jet"MidPoint R=0.7 |(jet#1)|<2
Charged Particles (||<1.0, PT>0.5 GeV/c)
PY Tune A
HW
Percent of ND = HC Cross-Section
90%100%
80%
40% 40%33%
5%10%
60%
33%
5% 10%
60%
34%
0%
25%
50%
75%
100%
Tune A TuneDW,D6T
Tune X1 Tune X2 Tune X1844 ATLAS
Per
cen
t o
f H
C
GG1
GG8
GG8 has larger <pT>!
"Toward" Average PT Charged
0.4
0.8
1.2
1.6
0 20 40 60 80 100
PT(Z-Boson) (GeV/c)
"To
war
d"
<P
T>
(G
eV/c
)
CDF Run 2 Preliminarydata corrected
generator level theory
"Drell-Yan Production"70 < M(pair) < 110 GeV
Charged Particles (||<1.0, PT>0.5 GeV/c)excluding the lepton-pair
HWJIM
ATLAS
pyAWpyDW
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 15
Tuning the Color ConnectionsTuning the Color Connections
Shows the charged particle ratio PTsum/Nchg in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 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).
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
GG8 has larger PTsum/Nchg!"Transverse" Charged Particle Ratio: PTsum/Nchg
0.4
0.7
1.0
1.3
1.6
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
"Tra
nsv
erse
" R
atio
(G
eV/c
) RDF PreliminaryATLAS corrected datagenerator level theory
7 TeV
Charged Particles (||<2.5, PT>0.5 GeV/c)
X18GG8
X18GG1
X18QQ
Percent of ND = HC Cross-Section
90%100%
80%
40% 40%33%
5%10%
60%
33%
5% 10%
60%
34%
0%
25%
50%
75%
100%
Tune A TuneDW,D6T
Tune X1 Tune X2 Tune X1844 ATLAS
Per
cen
t o
f H
C
GG1
GG8
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 16
PYTHIA Tune X1PYTHIA Tune X1
ATLAS preliminary data at 900 GeV and 7 TeV on the “transverse” charged PTsum density, dPT/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 2.5. The data are corrected and compared with PYTHIA Tune X1 at the generrator level.
ATLAS preliminary data at 900 GeV and 7 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 2.5. The data are corrected and compared with PYTHIA Tune X1 at the generator level.
"Transverse" Charged Particle Density: dN/dd
0.0
0.4
0.8
1.2
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
"Tra
nsv
erse
" C
har
ged
Den
sity RDF Preliminary
ATLAS corrected dataTune X1 generator level
900 GeV
7 TeV
Charged Particles (||<2.5, PT>0.5 GeV/c)
"Transverse" Charged PTsum Density: dPT/dd
0.0
0.5
1.0
1.5
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
PT
sum
Den
sity
(G
eV/c
)
RDF PreliminaryATLAS corrected data
Tune X1 generator level
900 GeV
7 TeV
Charged Particles (||<2.5, PT>0.5 GeV/c)
Tune X1 → Tune CWPARP(82) = 1.9 → 1.8PARP(85) = 1.0 → 0.8PARP(86) = 1.0 → 0.9
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 17
PYTHIA Tune X1PYTHIA Tune X1
Ratio of the ATLAS preliminary data on the charged PTsum density in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 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 particle density in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 2.5) at 900 GeV and 7 TeV as defined by PTmax compared with PYTHIA Tune X1 at the generator level.
Tune X1 → Tune CWPARP(82) = 1.9 → 1.8PARP(85) = 1.0 → 0.8PARP(86) = 1.0 → 0.9
"Transverse" Charged Particle Density: dN/dd
0.0
1.0
2.0
3.0
4.0
0 1 2 3 4 5 6 7 8 9 10 11 12
PTmax (GeV/c)
Rat
io:
7 T
eV/9
00 G
eV
Charged Particles (||<2.5, PT>0.5 GeV/c) 7 TeV / 900 GeV
RDF PreliminaryATLAS corrected data
Tune X1 generator level
"Transverse" Charged PTsum Density: dPT/dd
0.0
1.0
2.0
3.0
4.0
0 1 2 3 4 5 6 7 8 9 10 11 12
PTmax (GeV/c)
Rat
io:
7 T
eV/9
00 G
eV
Charged Particles (||<2.5, PT>0.5 GeV/c) 7 TeV / 900 GeV
RDF PreliminaryATLAS corrected data
Tune X1 generator level
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 18
PYTHIA Tune X1PYTHIA Tune X1
Ratio of the ATLAS preliminary data on the charged PTsum density in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 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 particle density in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 2.5) at 900 GeV and 7 TeV as defined by PTmax compared with PYTHIA Tune X1 at the generator level.
Tune X1 → Tune CWPARP(82) = 1.9 → 1.8PARP(85) = 1.0 → 0.8PARP(86) = 1.0 → 0.9
"Transverse" Charged Particle Density: dN/dd
0.0
1.0
2.0
3.0
4.0
0 1 2 3 4 5 6 7 8 9 10 11 12
PTmax (GeV/c)
Rat
io:
7 T
eV/9
00 G
eV
Charged Particles (||<2.5, PT>0.5 GeV/c) 7 TeV / 900 GeV
RDF PreliminaryATLAS corrected data
Tune X1 generator level
"Transverse" Charged PTsum Density: dPT/dd
0.0
1.0
2.0
3.0
4.0
0 1 2 3 4 5 6 7 8 9 10 11 12
PTmax (GeV/c)
Rat
io:
7 T
eV/9
00 G
eV
Charged Particles (||<2.5, PT>0.5 GeV/c) 7 TeV / 900 GeV
RDF PreliminaryATLAS corrected data
Tune X1 generator level
"Transverse" Charged Particle Ratio: PTsum/Nchg
0.4
0.7
1.0
1.3
1.6
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
"Tra
nsv
erse
" R
atio
(G
eV/c
)
Charged Particles (||<2.5, PT>0.5 GeV/c) 7 TeV
RDF PreliminaryATLAS corrected data
Tune X1 generator level
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 19
Shows the data on the dependence of the “associated” charged particle density, dNchg/dd, for charged particles (pT > 0.5 GeV/c, || < 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).
PTmax Direction
Correlations in
Associated Particle Density: dN/dd
0.0
0.2
0.4
0.6
0.8
1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
(degrees)
As
so
cia
ted
Pa
rtic
le D
en
sit
y
PTmax > 2.0 GeV/c
PY Tune A
PTmax > 0.5 GeV/c
PY Tune A
CDF Preliminarydata uncorrectedtheory + CDFSIM
PTmaxPTmax not included (||<1.0, PT>0.5 GeV/c)
PY Tune A 1.96 TeV
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”).
PTmax > 2.0 GeV/c
PTmax > 0.5 GeV/c
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
Transverse Region Transverse
Region
PY Tune A
CDF Run 2 Min-Bias “Associated”CDF Run 2 Min-Bias “Associated”Charged Particle DensityCharged Particle Density
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 20
Shows the data on the dependence of the “associated” charged particle density, dNchg/dd, for charged particles (pT > 0.5 GeV/c, || < 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).
PTmax Direction
Correlations in
Associated Particle Density: dN/dd
0.0
0.2
0.4
0.6
0.8
1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
(degrees)
As
so
cia
ted
Pa
rtic
le D
en
sit
y
PTmax > 2.0 GeV/c
PY Tune A
PTmax > 0.5 GeV/c
PY Tune A
CDF Preliminarydata uncorrectedtheory + CDFSIM
PTmaxPTmax not included (||<1.0, PT>0.5 GeV/c)
PY Tune A 1.96 TeV
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”).
PTmax > 2.0 GeV/c
PTmax > 0.5 GeV/c
PTmax Direction
“Toward”
“Transverse” “Transverse”
“Away”
Transverse Region Transverse
Region
PY Tune A
CDF Run 2 Min-Bias “Associated”CDF Run 2 Min-Bias “Associated”Charged Particle DensityCharged Particle Density
The problem in fitting the “toward”associated particle density seen
10 years ago at CDF also appearsat 900 GeV and 7 TeV inthe ATLAS & CMS data!
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 21
UE SummaryUE SummaryThe “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!
“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.
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
PARP(90)
Color
Connections
PARP(82)
Diffraction
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 22
<PT> versus Nchg<PT> versus Nchg
Shows how changing the color connections affects the <pT> versus Nchg . Here the data and theory are non-diffractive (ND). Here you can understand why Tune DW rises faster than the data and why the ATLAS tunes does so poorly.
Average PT versus Nchg
0.6
0.8
1.0
1.2
1.4
0 5 10 15 20 25 30 35 40 45
Number of Charged Particles
Ave
rag
e P
T (
GeV
/c)
CDF Run 2 Publisheddata corrected
generator level theory
Charged Particles (||<1.0, PT>0.4 GeV/c)
ND 1.96 TeV
ATLAS
pyDW pyA
Average PT versus Nchg
0.6
0.8
1.0
1.2
1.4
0 5 10 15 20 25 30 35 40 45
Number of Charged Particles
Ave
rag
e P
T (
GeV
/c)
CDF Published Data
pyX18GG8 Run2
pyX18GG1 Run2
pyX18QQ Run2
CDF Run 2 Publisheddata corrected
generator level theory
Charged Particles (||<1.0, PT>0.4 GeV/c)
ND 1.96 TeV
The CDF “min-bias” data aretelling us that the correct tune
must be largely GG8!Okay Tune A and DW have
a little to much GG8!
CDF ND data on the <pT> versus Nchg compared with Tune A(ND), Tune DW(ND) and Tune ATLAS MC08(ND). This is why no one likes the ATLAS MC08 Tune!
Percent of ND = HC Cross-Section
90%100%
80%
40% 40%33%
5%10%
60%
33%
5% 10%
60%
34%
0%
25%
50%
75%
100%
Tune A TuneDW,D6T
Tune X1 Tune X2 Tune X1844 ATLAS
Per
cen
t o
f H
C
GG1
GG8
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 23
<PT> versus Nchg<PT> versus Nchg
Shows how changing the color connections affects the <pT> versus Nchg . Here the data and theory are non-diffractive (ND). Here you can understand why Tune DW rises faster than the data and why the ATLAS tunes does so poorly.
Average PT versus Nchg
0.6
0.8
1.0
1.2
1.4
0 5 10 15 20 25 30 35 40 45
Number of Charged Particles
Ave
rag
e P
T (
GeV
/c)
CDF Run 2 Publisheddata corrected
generator level theory
Charged Particles (||<1.0, PT>0.4 GeV/c)
ND 1.96 TeV
ATLAS
pyDW pyA
Average PT versus Nchg
0.6
0.8
1.0
1.2
1.4
0 5 10 15 20 25 30 35 40 45
Number of Charged Particles
Ave
rag
e P
T (
GeV
/c)
CDF Published Data
pyX18GG8 Run2
pyX18GG1 Run2
pyX18QQ Run2
CDF Run 2 Publisheddata corrected
generator level theory
Charged Particles (||<1.0, PT>0.4 GeV/c)
ND 1.96 TeV
The CDF “min-bias” data aretelling us that the correct tune
must be largely GG8!Okay Tune A and DW have
a little to much GG8!
CDF ND data on the <pT> versus Nchg compared with Tune A(ND), Tune DW(ND) and Tune ATLAS MC08(ND). This is why no one likes the ATLAS MC08 Tune!
Percent of ND = HC Cross-Section
90%100%
80%
40% 40%33%
5%10%
60%
33%
5% 10%
60%
34%
0%
25%
50%
75%
100%
Tune A TuneDW,D6T
Tune X1 Tune X2 Tune X1844 ATLAS
Per
cen
t o
f H
C
GG1
GG8
Average PT versus Nchg
0.6
0.8
1.0
1.2
1.4
0 5 10 15 20 25 30 35 40 45
Number of Charged Particles
Ave
rag
e P
T (
GeV
/c)
CDF Published Data
pyX188090
CDF Run 2 Publisheddata corrected
generator level theory
Charged Particles (||<1.0, PT>0.4 GeV/c)
ND 1.96 TeV
80% GG810% GG110% QQ
Tune X1!
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 24
PYTHIA Tune X2PYTHIA Tune X2
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.
For Tune X2 I will attempt to produce enough charged particles (all pT) at 7 TeV (i.e. fit the CMS NSD dN/d 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!
Percent of INEL Cross-Section
66.5%76.7%
67.9%78.3%
22.3%15.3%
19.2%13.2%
11.2% 8.0% 12.9% 9.2%
0%
25%
50%
75%
100%
PY 900 ALICE 900 PY 7 TEV Tune X3 7 TeV
Pe
rce
nt
INE
L
DD
SD
HC
Percent of NSD Cross-Section
85.6% 90.6%84.1% 89.0%
14.4% 9.4%15.9% 10.4%
0%
25%
50%
75%
100%
PY 900 ALICE 900 PY 7 TEV Tune X3 7 TeV
Pe
rce
nt
NS
D
DD
HC
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 25
Color ConnectionsColor ConnectionsAverage Number of Charged Particles
66.4
93.2
79.9
14.1 17.0
68.3
98.8
83.9
14.1 17.0
70.3
104.8
88.4
14.1 17.0
0
20
40
60
80
100
120
GG8 GG1 QQbar SD DD
Av
erag
e N
ch
g
PARP(82)=1.8
PARP(82)=1.7
PARP(82)=1.6
All pT All 7 TeV Average Number of Charged Particles
20.5
34.0
27.7
3.0 3.0
21.2
36.4
29.4
3.0 3.0
21.9
39.1
31.3
3.0 3.0
0
5
10
15
20
25
30
35
40
45
GG8 GG1 QQbar SD DD
Av
erag
e N
ch
g
PARP(82)=1.8
PARP(82)=1.7
PARP(82)=1.6
All pT ||<2
7 TeV
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, || < 2). Percent of ND = HC Cross-Section
90%100%
80%
40% 40%33%
5%10%
60%
33%
5% 10%
60%
34%
0%
25%
50%
75%
100%
Tune A TuneDW,D6T
Tune X1 Tune X2 Tune X1844 ATLAS
Per
cen
t o
f H
C
GG1
GG8
CMS
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 26
Color ConnectionsColor Connections
Generator level dN/d (all pT). Shows the HC contribution for the three color connections GG8, GG1, and QQbar. Also shows the CMS NSD data.
Charged Particle Density: dN/d
0
2
4
6
8
10
12
-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
Ch
arg
ed P
arti
cle
Den
sity
CMS NSD 7 TeV
pyX18GG1 HC (8.2)
pyX18QQ HC (6.7)
pyX18GG8 HC (4.9)
7 TeV
Charged Particles (all PT)
RDF Preliminarydata CMS NSD
generator level theory
DW, DWT, and D6T are 100% GG8!
pyATLAS is equal mixtures of all three!
Percent of ND = HC Cross-Section
90%100%
80%
40% 40%33%
5%10%
60%
33%
5% 10%
60%
34%
0%
25%
50%
75%
100%
Tune A TuneDW,D6T
Tune X1 Tune X2 Tune X1844 ATLAS
Per
cen
t o
f H
C
GG1
GG8
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 27
PYTHIA Tune X2PYTHIA Tune X2
Generator level dN/d (all pT). Shows the NSD = HC + DD, HC = ND, and DD contributions for Tune X2. Also shows the CMS NSD data.
Charged Particle Density: dN/d
0
2
4
6
8
10
12
-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
Ch
arg
ed P
arti
cle
Den
sity
CMS NSD 7 TeV
pyX2 HC (6.87)
pyX2 NSD (5.91)
pyDD (0.7)
7 TeV
Charged Particles (all PT)
RDF Preliminarydata CMS NSD
generator level theory60% GG140% GG8
84% HC16% DD
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 28
PYTHIA Tune X2PYTHIA Tune X2
Shows the CMS NSD data for dN/d (all pT) and the ATLAS INEL data for dN/d (pT > 0.5 GeV/c, Nchg ≥ 1) compared with Tune X2 (generator level).
Charged Particle Density: dN/d
0
2
4
6
8
-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
Ch
arg
ed P
arti
cle
Den
sity
RDF Preliminary
Tune X2 7 TeV
CMS NSD all pT
ATLAS INEL pT > 0.5 GeV/c Nchg ≥ 1
SD = 9.4%, DD = 6.8%!
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 29
Color ConnectionsColor ConnectionsAverage Charged Particle PT
0.53
0.44
0.48
0.33 0.34
0.54
0.44
0.48
0.33 0.34
0.54
0.43
0.48
0.33 0.34
0.20
0.30
0.40
0.50
0.60
0.70
GG8 GG1 QQbar SD DD
Av
erag
e P
T (
GeV
/c)
PARP(82)=1.8
PARP(82)=1.7
PARP(82)=1.6
All pT All 7 TeV Average Charged Particle PT
0.62
0.47
0.53
0.36 0.36
0.63
0.47
0.52
0.36 0.36
0.64
0.46
0.52
0.36 0.36
0.20
0.30
0.40
0.50
0.60
0.70
GG8 GG1 QQbar SD DD
Av
erag
e P
T (
GeV
/c)
PARP(82)=1.8
PARP(82)=1.7
PARP(82)=1.6
All pT || < 2
7 TeV
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)!
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, || < 2).
CMS
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 30
PYTHIA Tune X2PYTHIA Tune X2
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).
Average PT versus Nchg
0.6
0.8
1.0
1.2
1.4
0 10 20 30 40 50 60 70 80 90
Number of Charged Particles
Ave
rag
e P
T (
GeV
/c)
7 TeV INELpT > 0.5 GeV/c || < 2.5
RDF PreliminaryATLAS INEL data
generator level theory
Tune X2
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 31
Color ConnectionsColor Connections
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).
Average PT versus Nchg
0.6
0.8
1.0
1.2
1.4
0 10 20 30 40 50 60 70 80 90
Number of Charged Particles
Ave
rag
e P
T (
GeV
/c)
7 TeVpT > 0.5 GeV/c || < 2.5
RDF PreliminaryATLAS INEL data
generator level theory
pyX18GG8
pyX18GG1
pyX18QQ
Average PT versus Nchg
0.6
0.8
1.0
1.2
1.4
0 10 20 30 40 50 60 70 80 90
Number of Charged Particles
Ave
rag
e P
T (
GeV
/c)
7 TeV INELpT > 0.5 GeV/c || < 2.5
RDF PreliminaryATLAS INEL data
generator level theory
Tune X1844
Percent of ND = HC Cross-Section
90%100%
80%
40% 40%33%
5%10%
60%
33%
5% 10%
60%
34%
0%
25%
50%
75%
100%
Tune A TuneDW,D6T
Tune X1 Tune X2 Tune X1844 ATLAS
Per
cen
t o
f H
C
GG1
GG8
Gives the right <pT>!
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 32
Color ConnectionsColor Connections
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).
Average PT versus Nchg
0.6
0.8
1.0
1.2
1.4
0 10 20 30 40 50 60 70 80 90
Number of Charged Particles
Ave
rag
e P
T (
GeV
/c)
7 TeVpT > 0.5 GeV/c || < 2.5
RDF PreliminaryATLAS INEL data
generator level theory
pyX18GG8
pyX18GG1
pyX18QQ
Average PT versus Nchg
0.6
0.8
1.0
1.2
1.4
0 10 20 30 40 50 60 70 80 90
Number of Charged Particles
Ave
rag
e P
T (
GeV
/c)
7 TeV INELpT > 0.5 GeV/c || < 2.5
RDF PreliminaryATLAS INEL data
generator level theory
Tune X1844
Percent of ND = HC Cross-Section
90%100%
80%
40% 40%33%
5%10%
60%
33%
5% 10%
60%
34%
0%
25%
50%
75%
100%
Tune A TuneDW,D6T
Tune X1 Tune X2 Tune X1844 ATLAS
Per
cen
t o
f H
C
GG1
GG8
Charged Particle Density: dN/d
0
2
4
6
8
-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
Ch
arg
ed P
arti
cle
Den
sity
CMS Preliminary
7 TeV NSD All pT
CMS NSD all pTTune X2
Tune X1844
UE&MB Working Group Meeting LPCC May 31, 2010
Rick Field – Florida/CDF/CMS Page 33
Min-Bias SummaryMin-Bias Summary
I think the problem is that we do not understand diffraction well enough yet!
We are a long way from having a model that will fit all the features of the LHC min-bias data!
We are learning a lot about how nature works!
PARP(90)
Color
Connections
PARP(82)
Diffraction