MPI@LHC 2010
New LHC Tunes: What we have learned
Rick Field
University of Florida
Outline of Talk
 The CDF Tevatron tunes do not produce enough soft
particles.
Glasgow, Scotland November 2010
 PYTHIA 6.4 Tune Z1: New CMS 6.4 MB tune (pT-
Outgoing Parton
PT(hard)
ordered parton showers and new MPI).
Initial-State Radiation
Proton
 Examine how well the Tune Z1 fits the LHC UE
Proton
Underlying Event
Underlying Event
data (CMS, ATLAS, ALICE).
 Examine how well Tune Z1 fits the LHC MB
Outgoing Parton
“Minimum Bias” Collisions
data (CMS,ATLAS, ALICE).
Proton
MPI@LHC 2010
Glasgow, November 30, 2010
Final-State
Radiation
Rick Field – Florida/CDF/CMS
Proton
Page 1
PYTHIA Tune DW
If one increases the pT
the agreement
improves!
Charged Particle Density: dN/dh
5
Charged Particle Density
RDF Preliminary
4
At Least 1 Charged Particle |h| < 0.8
900 GeV
ALICE INEL data
pyDW generator level
pT > 0.15 GeV/c
Tune DW
3
pT > 0.5 GeV/c
2
pT > 1.0 GeV/c
1
0
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
PseudoRapidity h
 ALICE inelastic data at 900 GeV on the dN/dh distribution for charged particles (pT >
PTmin) for events with at least one charged particle with pT > PTmin and |h| < 0.8 for
PTmin = 0.15 GeV/c, 0.5 GeV/c, and 1.0 GeV/c compared with PYTHIA Tune DW at the
generator level.
“Minimum Bias” Collisions
ProtonThe
same thing occurs at 7 TeV!
Proton
ALICE, ATLAS, and CMS data coming soon.
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 2
PYTHIA Tune DW
Diffraction
contributes less at
harder scales!
Charged Particle Density: dN/dh
5
Charged Particle Density
RDF Preliminary
4
At Least 1 Charged Particle |h| < 0.8
900 GeV
ALICE INEL data
pyDW generator level
pT > 0.15 GeV/c
3
Tune DW
pT > 0.5 GeV/c
2
pT > 1.0 GeV/c
1
dashed = ND solid = INEL
0
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
PseudoRapidity h
 ALICE inelastic data at 900 GeV on the dN/dh distribution for charged particles (pT >
PTmin) for events with at least one charged particle with pT > PTmin and |h| < 0.8 for
PTmin = 0.15 GeV/c, 0.5 GeV/c, and 1.0 GeV/c compared with PYTHIA Tune Z1 at the
generator level (dashed = ND, solid = INEL).
“Minimum Bias” Collisions
Proton
Cannot
trust PYTHIA 6.2 modeling of diffraction!
Proton
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 3
CMS dN/dh
Charged Particle Density: dN/dh
8
CMS
Charged Particle Density
7 TeV
6
4
RDF Preliminary
2
Tune DW
CMS NSD data
pyDW generator level
All pT
dashed = ND solid = NSD
0
-3.0
-2.5
-2.0
-1.5
-1.0
Soft particles!
-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 and the HC = ND
contributions for Tune DW. Also shows the CMS NSD data.
Off by 50%!
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 4
CMS dN/dh
Charged Particle Density: dN/dh
8
CMS
Charged Particle Density
7 TeV
6
4
RDF Preliminary
CMS NSD data
pyDW generator level
Tune DW
Okay if the Monte-Carlo does not fit
dashedthe
= ND solid
= NSD
data
what do we do? All pT
0
We tune the Monte-Carlo
-3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0
0.5
1.0
1.5
2.0
to fit the
data!
PseudoRapidity h
2
Soft particles!
2.5
3.0
 Generator level dN/dh (all pT). Shows the NSD = HC + DD and the HC = ND
contributions for Tune DW. Also shows the CMS NSD data.
Off by 50%!
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 5
CMS dN/dh
Charged Particle Density: dN/dh
8
Charged Particle Density
7 TeV
CMS
6
4
RDF Preliminary
Okay if the Monte-Carlo doesTune
not DW
fit
Soft particles!
2
the data what do we do?
dashed = ND solid = NSD
All pT
We
tune
the
Monte-Carlo
0
-3.0 -2.5 -2.0 -1.5
-1.0 the
-0.5 data!
0.0
0.5
1.0
1.5
2.0
2.5
3.0
to fit
PseudoRapidity h
Be careful not to tune
away new physics!
 Generator level dN/dh (all pT). Shows the NSD = HC + DD and the HC = ND
contributions for Tune DW. Also shows the CMS NSD data.
CMS NSD data
pyDW generator level
Off by 50%!
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 6
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!
MPI@LHC 2010
Glasgow, November 30, 2010
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 7
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
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 8
PYTHIA Tune Z1
"Transverse" Charged Particle Density: dN/dhdf
"Transverse" Charged Particle Density: dN/dhdf
1.2
1.2
CMS Preliminary
D6T
7 TeV
data uncorrected
Theory + SIM
Charged Particle Density
Charged Particle Density
CMS Preliminary
0.8
900 GeV
DW
0.4
CMS
7 TeV
data uncorrected
pyZ1 + SIM
0.8
900 GeV
0.4
CMS
Tune Z1
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
30
35
40
45
50
0
5
10
15
20
25
30
35
40
45
50
PT(chgjet#1) GeV/c
PT(chgjet#1) GeV/c
 CMS preliminary data at 900 GeV and 7 TeV  CMS preliminary data at 900 GeV and 7 TeV
on the “transverse” charged particle density,
on the “transverse” charged particle density,
dN/dhdf, as defined by the leading charged
dN/dhdf, as defined by 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| < 2.0. The data
with pT > 0.5 GeV/c and |h| < 2.0. The data
are uncorrected and compared with PYTHIA
are uncorrected and compared with PYTHIA
Tune DW and D6T after detector simulation
Tune Z1 after detector simulation (SIM).
(SIM).
Color reconnection suppression.
Color reconnection strength.
MPI@LHC 2010
Glasgow, November 30, 2010
Tune Z1 (CTEQ5L)
PARP(82) = 1.932
PARP(90) = 0.275
PARP(77) = 1.016
PARP(78) = 0.538
Rick Field – Florida/CDF/CMS
Tune Z1 is a PYTHIA 6.4 using
pT-ordered parton showers and
the new MPI model!
Page 9
PYTHIA Tune Z1
"Transverse" Charged PTsum Density: dPT/dhdf
CMS Preliminary
D6T
data uncorrected
Theory + SIM
1.2
Charged PTsum Density (GeV/c)
Charged PTsum Density (GeV/c)
"Transverse" Charged PTsum Density: dPT/dhdf
1.6
7 TeV
0.8
DW
900 GeV
CMS
0.4
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0
5
10
15
20
25
30
35
40
45
50
1.6
CMS Preliminary
7 TeV
data uncorrected
pyZ1 + SIM
1.2
0.8
900 GeV
CMS
0.4
Tune Z1
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0
5
PT(chgjet#1) (GeV/c)
10
15
20
25
30
35
40
45
50
PT(chgjet#1) (GeV/c)
 CMS preliminary data at 900 GeV and 7 TeV  CMS preliminary data at 900 GeV and 7 TeV
on the “transverse” charged PTsum density,
on the “transverse” charged PTsum density,
dPT/dhdf, as defined by the leading charged
dPT/dhdf, as defined by 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| < 2.0. The data
with pT > 0.5 GeV/c and |h| < 2.0. The data
are uncorrected and compared with PYTHIA
are uncorrected and compared with PYTHIA
Tune DW and D6T after detector simulation
Tune Z1 after detector simulation (SIM).
(SIM).
Color reconnection suppression.
Color reconnection strength.
MPI@LHC 2010
Glasgow, November 30, 2010
Tune Z1 (CTEQ5L)
PARP(82) = 1.932
PARP(90) = 0.275
PARP(77) = 1.016
PARP(78) = 0.538
Rick Field – Florida/CDF/CMS
Tune Z1 is a PYTHIA 6.4 using
pT-ordered parton showers and
the new MPI model!
Page 10
PYTHIA Tune Z1
"Transverse" Charged PTsum Density: dPT/dhdf
1.2
1.5
RDF Preliminary
RDF Preliminary
7 TeV
ATLAS corrected data
Tune Z1 generator level
PTsum Density (GeV/c)
"Transverse" Charged Density
"Transverse" Charged Particle Density: dN/dhdf
0.8
900 GeV
0.4
ATLAS
Tune Z1
7 TeV
ATLAS corrected data
Tune Z1 generator level
1.0
900 GeV
0.5
ATLAS
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
Tune Z1
0.0
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
0
2
4
6
8
10
12
14
16
18
20
0
2
PTmax (GeV/c)
MPI@LHC 2010
Glasgow, November 30, 2010
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 Z1 at the generator level.
Color reconnection suppression.
Color reconnection strength.
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 Z1 at the generrator level.
Tune Z1 (CTEQ5L)
PARP(82) = 1.932
PARP(90) = 0.275
PARP(77) = 1.016
PARP(78) = 0.538
Rick Field – Florida/CDF/CMS
Tune Z1 is a PYTHIA 6.4 using
pT-ordered parton showers and
the new MPI model!
Page 11
20
PYTHIA Tune Z1
"Transverse" Charged PTsum Density: dPT/dhdf
"Transverse" Charged Particle Density: dN/dhdf
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 (|h|<0.8, PT>0.5 GeV/c)
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
0
 ALICE 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| < 0.8.
The data are corrected and compared with
PYTHIA Tune Z1 at the generator level.
MPI@LHC 2010
Glasgow, November 30, 2010
10
15
20
25
PTmax (GeV/c)
PTmax (GeV/c)
Color reconnection suppression.
Color reconnection strength.
5
 ALICE 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| < 0.8.
The data are corrected and compared with
PYTHIA Tune Z1 at the generrator level.
Tune Z1 (CTEQ5L)
PARP(82) = 1.932
PARP(90) = 0.275
PARP(77) = 1.016
PARP(78) = 0.538
Rick Field – Florida/CDF/CMS
Tune Z1 is a PYTHIA 6.4 using
pT-ordered parton showers and
the new MPI model!
Page 12
PYTHIA Tune Z1
1.2
RDF Preliminary
ALICE corrected data
Tune Z1 generator level
0.8
0.4
"Transverse" Charged Density
"Transverse" Charged Density
1.2
Tune Z1
0.0
0
5
7 TeV
RDF Preliminary
|h| < 0.8
Tune Z1 generator level
0.8
900 GeV
ALICE
|h| < 2.5
0.4
"Transverse"
Charged Particle Density: dN/dhdf
Particle Density:
dN/dhdf
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
"Transverse" Charged Density
"Transverse" Charged Particle
Density: dN/dhdf
"Transverse"
Charged
1.2
RDF Preliminary
7 TeV
ATLAS corrected data
Tune Z1 generator level
0.8
900 GeV
0.4
ATLAS
Tune Z1
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
10
15
20
7 TeV
PTmax (GeV/c)
25
0
2
4
12
Charged
Particles
(PT6 > 0.5 8GeV/c)10
PTmax (GeV/c)
14
16
18
0.0
 ALICE preliminary data
and 710  ATLAS
preliminary
data25at 900 GeV and 7
0 at 900 GeV
5
15
20
TeV on the “transverse” charged particle PTmax (GeV/c)
TeV on the “transverse” charged particle
density, dN/dhdf, as defined by the leading
density, dN/dhdf, as defined by the leading
charged particle (PTmax) for charged
charged particle (PTmax) for charged
particles with pT > 0.5 GeV/c and |h| < 0.8.
particles with pT > 0.5 GeV/c and |h| < 2.5.
The data are corrected and compared with
The data are corrected and compared with
PYTHIA Tune Z1 at the generator level.
PYTHIA Tune Z1 at the generrator level.
Color reconnection suppression.
Color reconnection strength.
MPI@LHC 2010
Glasgow, November 30, 2010
Tune Z1 (CTEQ5L)
PARP(82) = 1.932
PARP(90) = 0.275
PARP(77) = 1.016
PARP(78) = 0.538
Rick Field – Florida/CDF/CMS
Tune Z1 is a PYTHIA 6.4 using
pT-ordered parton showers and
the new MPI model!
Page 13
20
PYTHIA Tune Z1
"Transverse" Charged Particle Density: dN/dhdf
"Transverse" Charged Particle Density: dN/dhdf
3.0
3.0
CMS Preliminary
DW
D6T
data uncorrected
theory + SIM
Ratio: 7 TeV/900 GeV
Ratio: 7 TeV/900 GeV
CMS Preliminary
2.0
P0
1.0
CW
CMS
7 TeV / 900 GeV
Tune Z1
data uncorrected
pyZ1 + SIM
2.0
1.0
CMS
7 TeV / 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
PT(chgjet#1) (GeV/c)
6
8
10
12
14
16
18
PT(chgjet#1) (GeV/c)
 Ratio of CMS preliminary data at 900 GeV
and 7 TeV (7 TeV divided by 900 GeV) on the
“transverse” charged particle density as
defined by the leading charged particle jet
(chgjet#1) for charged particles with pT > 0.5
GeV/c and |h| < 2.0. The data are
uncorrected and compared with PYTHIA
Tune DW, D6T, CW, and P0 after detector
simulation (SIM).
MPI@LHC 2010
Glasgow, November 30, 2010
4
 Ratio of CMS preliminary data at 900 GeV
and 7 TeV (7 TeV divided by 900 GeV) on the
“transverse” charged particle density as
defined by the leading charged particle jet
(chgjet#1) for charged particles with pT > 0.5
GeV/c and |h| < 2.0. The data are
uncorrected and compared with PYTHIA
Tune Z1 after detector simulation (SIM).
Rick Field – Florida/CDF/CMS
Page 14
PYTHIA Tune Z1
"Transverse" Charged PTsum Density: dPT/dhdf
3.0
D6T
CMS Preliminary
CMS Preliminary
DW
data uncorrected
theory + SIM
Ratio: 7 TeV/900 GeV
Ratio: 7 TeV/900 GeV
"Transverse" Charged PTsum Density: dPT/dhdf
3.0
2.0
P0
CW
1.0
CMS
7 TeV / 900 GeV
data uncorrected
pyZ1 + SIM
Tune Z1
2.0
1.0
CMS
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
7 TeV / 900 GeV
0.0
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
0.0
0
2
4
6
8
10
12
14
16
18
0
2
PT(chgjet#1) (GeV/c)
6
8
10
12
14
16
18
PT(chgjet#1) (GeV/c)
 Ratio of CMS preliminary data at 900 GeV
and 7 TeV (7 TeV divided by 900 GeV) on the
“transverse” charged PTsum density as
defined by the leading charged particle jet
(chgjet#1) for charged particles with pT > 0.5
GeV/c and |h| < 2.0. The data are
uncorrected and compared with PYTHIA
Tune DW, D6T, CW, and P0 after detector
simulation (SIM).
MPI@LHC 2010
Glasgow, November 30, 2010
4
 Ratio of CMS preliminary data at 900 GeV
and 7 TeV (7 TeV divided by 900 GeV) on the
“transverse” charged PTsum density as
defined by the leading charged particle jet
(chgjet#1) for charged particles with pT > 0.5
GeV/c and |h| < 2.0. The data are
uncorrected and compared with PYTHIA
Tune Z1 after detector simulation (SIM).
Rick Field – Florida/CDF/CMS
Page 15
PYTHIA Tune Z1
"Transverse" Charged Particle Density: dN/dhdf
"Transverse" Charged PTsum Density: dPT/dhdf
4.0
3.0
RDF Preliminary
RDF Preliminary
ATLAS corrected data
Tune Z1 generator level
ATLAS corrected data
Tune Z1 generator level
Ratio: 7 TeV/900 GeV
Ratio: 7 TeV/900 GeV
4.0
Tune Z1
2.0
ATLAS
1.0
7 TeV / 900 GeV
3.0
Tune Z1
2.0
1.0
ATLAS
7 TeV / 900 GeV
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
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
0
1
PTmax (GeV/c)
3
4
5
6
7
8
9
10
11
12
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 Z1 at
the generator level.
MPI@LHC 2010
Glasgow, November 30, 2010
2
 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 Z1 at
the generator level.
Rick Field – Florida/CDF/CMS
Page 16
PYTHIA Tune Z1
"Transverse" Charged Particle Density: dN/dhdf
1.5
1.0
0.5
"Transverse" Ratio 0.1/0.5
7 TeV
ATLAS corrected data
Tune Z1 generator level
2.0
PT > 0.1 GeV/c
4.0
RDF Preliminary
3.0
2.0
0.0
2
4
6
ATLAS
Factor of 2 increase!
Charged Particles (|h|<2.5)
10
7 TeV
RDF Preliminary
2.0
PT > 0.1 GeV/c
generator level
Tune Z1 (solid)
Tune DW (dashed)
1.0
ATLAS
0.5
PT > 0.5 GeV/c
Tune Z1
Charged Particles (|h|<2.5)
0.0
1.0
8
RDF Preliminary
ATLAS corrected data
Tune Z1 generator level
Charge Particle1.5
Density
PT > 0.5 GeV/c
Tune Z1
0
"Transverse" PTsum Density
2.5
"Transverse" Charged Density
"Transverse" Charged PTsum Density: dPT/dhdf
"Transverse" Ratio: PT >2.50.1 and > 0.5 GeV/c
12
PTmax (GeV/c)
14
16
18
Charge PTsum Density
20
0
2
4
76 TeV 8
10
12
14
16
18
20
Charged Particles
(|h|<2.5)
PTmax
(GeV/c)
0.0
 ATLAS preliminary data0 at 72TeV 4on the6
 10
ATLAS
preliminary
data
at
7 TeV on the
8
12
14
16
18
20
“transverse” charged particle density,
“transverse” charged PTsum density,
PTmax (GeV/c)
dN/dhdf, as defined by the leading charged
dPT/dhdf, as defined by the leading charged
particle (PTmax) for charged particles with
particle (PTmax) for charged particles with
pT > 0.5 GeV/c and |h| < 2.5. The data are
pT > 0.5 GeV/c and |h| < 2.5. The data are
corrected and compared with PYTHIA Tune
corrected and compared with PYTHIA Tune
Z1 at the generator level. Also shows the
Z1 at the generator level. Also shows the
prediction of Tune Z1 for the “transverse”
prediction of Tune Z1 for the “transverse”
charged particle density with pT > 0.1 GeV/c
charged particle density with pT > 0.1 GeV/c
and |h| < 2.5.
and |h| < 2.5.
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 17
“Transverse” Multiplicity Distribution
Same hard"Transverse"
scale at Charged Particle Multiplicity
1.0E+00 centertwo different
PT(chgjet#1) > 3 GeV/c
CMS Preliminary
of-mass
energies!
data uncorrected
1.0E-01
"Transverse" Charged Particle Multiplicity
1.0E+00
PT(chgjet#1) > 3 GeV/c
CMS
1.0E-02
Probability
CMS
1.0E-02
Probability
CMS Preliminary
data uncorrected
Theory + SIM
1.0E-01
1.0E-03
7 TeV
900 GeV
1.0E-04
D6T
1.0E-05
pyZ1 + SIM
Tune Z1
1.0E-03
7 TeV
900 GeV
1.0E-04
1.0E-05
DW
Normalized to 1
Normalized to 1
1.0E-06
1.0E-06
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
1.0E-07
1.0E-07
0
5
10
15
20
25
30
35
40
Number of Charged Particles
0
5
10
15
20
25
30
35
40
Number of Charged Particles
Difficult to produce
 CMS uncorrected data at 900 GeV and 7 TeV on  CMS uncorrected data at 900 GeV and 7
enough events
TeV on the charged
particlewith
multiplicity
the charged particle multiplicity distribution in
large
“transverse”
the “transverse” region for charged particles (pT > distribution in the “transverse” region
multiplicity
lowGeV/c, |h|
for charged particles
(pT at
> 0.5
0.5 GeV/c, |h| < 2) as defined by the leading
hard
< 2) as defined by
the scale!
leading charged
charged particle jet with PT(chgjet#1) > 3 GeV/c
compared with PYTHIA Tune DW and Tune D6T particle jet with PT(chgjet#1) > 3 GeV/c
compared with PYTHIA Tune Z1 at the
at the detector level (i.e. Theory + SIM).
detector level (i.e. Theory + SIM).
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 18
“Transverse” PTsum Distribution
Same hard
scale at
"Transverse"
Charged PTsum Distribution
1.0E+00
two different
centerCMS Preliminary
PT(chgjet#1) > 3 GeV/c
data uncorrected
of-mass energies!
"Transverse" Charged PTsum Distribution
1.0E+00
CMS Preliminary
1.0E-01
data uncorrected
Theory + SIM
1.0E-02
CMS
7 TeV
D6T
1.0E-04
pyZ1+ SIM
Tune Z1
1.0E-02
1.0E-03
900 GeV
CMS
1.0E-01
Probability
Probability
PT(chgjet#1) > 3 GeV/c
7 TeV
1.0E-03
900 GeV
1.0E-04
DW
1.0E-05
1.0E-05
Normalized to 1
Normalized to 1
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
1.0E-06
1.0E-06
0
5
10
15
20
25
30
35
40
45
50
0
PTsum (GeV/c)
5
10
15
20
25
30
35
40
45
50
PTsum (GeV/c)
 CMS uncorrected data at 900 GeV and 7 TeV  CMS uncorrected data at 900 GeV and 7 TeV
Difficult
to produce
on the charged scalar PTsum distribution in
on the charged
scalar PTsum
distribution in
enough
events
with
the “transverse” region for charged particles
the “transverse” region for charged particles
large
“transverse”
(pT > 0.5 GeV/c, |h| < 2) as defined by the
(pT > 0.5 GeV/c,
|h| <
2) as defined by the
PTsum
leading charged particle jet with
leading charged particleatjetlow
with
hard
scale!
PT(chgjet#1) > 3 GeV/c compared with
PT(chgjet#1) > 3 GeV/c compared with
PYTHIA Tune DW, and Tune D6T at the
PYTHIA Tune Z1, at the detector level (i.e.
detector level (i.e. Theory + SIM).
Theory + SIM).
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 19
“Transverse” Multiplicity Distribution
"Transverse" Charged Particle Multiplicity
"Transverse" Charged Particle Multiplicity
Same
center-of-mass
1.0E+00
energy at two different 7 TeV
1.0E-01
hard scales!
CMS
1.0E+00
7 TeV
CMS Preliminary
data uncorrected
Theory + SIM
1.0E-01
CMS
1.0E-02
1.0E-02
data uncorrected
pyZ1 + SIM
Tune Z1
PT(chgjet#1) > 20 GeV/c
Probability
Probability
PT(chgjet#1) > 20 GeV/c
D6T
1.0E-03
CMS Preliminary
1.0E-04
PT(chgjet#1) > 3 GeV/c
1.0E-03
1.0E-04
PT(chgjet#1) > 3 GeV/c
1.0E-05
1.0E-05
DW
Normalized to 1
Normalized to 1
1.0E-06
1.0E-06
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
1.0E-07
1.0E-07
0
5
10
15
20
25
30
35
40
0
Number of Charged Particles
5
10
15
20
25
30
35
40
Number of Charged Particles
Difficult
 CMS uncorrected
datatoatproduce
7 TeV on the
 CMS uncorrected data at 7 TeV on the
enough
events with
charged particle
multiplicity
distribution in
charged particle multiplicity distribution in
large
“transverse”
region
for charged particles
the “transverse” region for charged particles the “transverse”
multiplicity
low by the
(pT > 0.5 GeV/c,
|h| < 2) as at
defined
(pT > 0.5 GeV/c, |h| < 2) as defined by the
hard scale!
jet with PT(chgjet#1)
leading charged particle jet with PT(chgjet#1) leading charged particle
> 3 GeV/c and PT(chgjet#1) > 20 GeV/c
> 3 GeV/c and PT(chgjet#1) > 20 GeV/c
compared with PYTHIA Tune DW and Tune compared with PYTHIA Tune Z1 at the
D6T at the detector level (i.e. Theory + SIM). detector level (i.e. Theory + SIM).
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 20
“Transverse” PTsum Distribution
Same center-of-mass
"Transverse" Charged PTsum Distribution
energy 1.0E+00
at two different
7 TeV
CMS Preliminary
hard scales!
data uncorrected
"Transverse" Charged PTsum Distribution
1.0E+00
7 TeV
CMS Preliminary
data uncorrected
Theory + SIM
1.0E-01
CMS
1.0E-02
CMS
1.0E-02
PT(chgjet#1) > 20 GeV/c
Probability
Probability
1.0E-01
1.0E-03
PT(chgjet#1) > 3 GeV/c
1.0E-04
pyZ1 + SIM
Tune Z1
PT(chgjet#1) > 20 GeV/c
1.0E-03
PT(chgjet#1) > 3 GeV/c
1.0E-04
D6T
Normalized to 1
1.0E-05
Normalized to 1
1.0E-05
DW
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
1.0E-06
1.0E-06
0
5
10
15
20
25
30
35
40
45
50
0
PTsum (GeV/c)
5
10
15
20
25
30
35
40
45
50
PTsum (GeV/c)
 CMS uncorrected data at 7 TeV on the charged  CMS uncorrected data at 7 TeV on the charged
Difficultintothe
produce
PTsum distribution
“transverse” region for
PTsum distribution in the “transverse” region
enough
events
with |h| < 2) as
charged particles (pT > 0.5 GeV/c,
for charged particles (pT > 0.5 GeV/c, |h| < 2)
“transverse”
defined by thelarge
leading
charged particle jet with
as defined by the leading charged particle jet
PTsum
lowPT(chgjet#1) > 20
PT(chgjet#1) > 3 GeV/catand
with PT(chgjet#1) > 3 GeV/c and PT(chgjet#1)
GeV/c compared hard
with scale!
PYTHIA Tune Z1 at the
> 20 GeV/c compared with PYTHIA Tune DW
detector level (i.e. Theory + SIM).
and Tune D6T at the detector level (i.e. Theory
+ SIM).
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 21
CMS dN/dh
Charged Particle Density: dN/dh
Charged Particle Density: dN/dh
8
RDF Preliminary
RDF Preliminary
Charged Particle Density
Charged Particle Density
8
6
Tune Z1
4
CMS
2
CMS NSD 7 TeV
7 TeV
pyZ1 HC (6.51)
pyZ1 NSD (5.58)
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
6
4
CMS
2
CMS NSD 7 TeV
7 TeV
pyX2 NSD (5.91)
pyZ1 NSD (5.58)
CMS NSD all pT
0
-3.0
-2.5
-2.0
PseudoRapidity h
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
PseudoRapidity h
 Generator level dN/dh (all pT). Shows
the NSD = HC + DD and the HC = ND
contributions for Tune Z1. Also shows
the CMS NSD data.
 Generator level dN/dh (all pT). Shows
the NSD = HC + DD prediction for
Tune Z1 and Tune X2. Also shows the
CMS NSD data.
Okay not perfect, but remember
we do not know if the DD is correct!
MPI@LHC 2010
Glasgow, November 30, 2010
3.0
Rick Field – Florida/CDF/CMS
Page 22
PYTHIA Tune Z1
Charged Particle Density: dN/dh
5
Charged Particle Density
RDF Preliminary
4
At Least 1 Charged Particle |h| < 0.8
900 GeV
ALICE INEL data
pyZ1 generator level
pT > 0.15 GeV/c
3
Tune Z1
pT > 0.5 GeV/c
2
pT > 1.0 GeV/c
1
0
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
PseudoRapidity h
 ALICE inelastic data at 900 GeV on the dN/dh distribution for charged particles (pT >
PTmin) for events with at least one charged particle with pT > PTmin and |h| < 0.8 for
PTmin = 0.15 GeV/c, 0.5 GeV/c, and 1.0 GeV/c compared with PYTHIA Tune DW at the
generator level.
“Minimum Bias” Collisions
Okay
not perfect, but remember
Proton
Proton
we do not know if the SD & DD are correct!
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 23
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, |h|<2.0)
Tune Z1
1.0E-04
0
20
40
60
80
100
Number of Charged Particles
 Generator level charged multiplicity distribution (all pT, |h| < 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
MPI@LHC 2010
Glasgow, November 30, 2010
Okay not perfect!
But not that bad!
Rick Field – Florida/CDF/CMS
Proton
Page 24
NSD: <pT> versus Nchg
Average PT versus Nchg
0.7
CMS 900 GeV |eta| < 2.4
pyZ1 NSD LHC09
pyZ1 LHC09 <pT>=0.489
0.5
CMS
0.4
CMS Preliminary
CMS 900 GeV <pT>=0.460
data corrected
generator level theory
900 GeV
Average PT (GeV/c)
Average PT (GeV/c)
CMS Preliminary
0.6
Average PT versus Nchg
0.7
data corrected
generator level theory
0.6
0.5
CMS
0.4
CMS 7 TeV |eta| < 2.4
CMS 7 TeV <pT>=0.545
pyZ1 NSD LHC7
pyZ1 NSD LHC7 <pT>=0.577
7 TeV
Charged Particles (|h|<2.4, All pT)
Charged Particles (|h|<2.4, All pT)
0.3
0.3
0
10
20
30
40
50
60
70
80
90 100 110 120 130 140 150
Number of Charged Particles
Overall average pT
0
10
20
30
40
50
60
70
80
90 100 110 120 130 140 150
Number of Charged Particles
Overall average pT
Shows the 900 GeV and 7 TeV CMS NSD corrected data on <pT> versus
Nchg (all pT, |h| < 2.4) compared with Tune Z1.
“Minimum Bias” Collisions
Proton
MPI@LHC 2010
Glasgow, November 30, 2010
Okay not perfect!
But not that bad!
Rick Field – Florida/CDF/CMS
Proton
Page 25
NSD: <pT> versus Nchg
Charged Multiplicity Distribution
1.0E-01
“Minimum Bias” Collisions
RDF Preliminary
data CMS NSD
pyZ1 generator level
Proton
Probability
1.0E-02
Proton
7 TeV
900 GeV
1.0E-03
Charged Particles
(all PT, |h|<2.0)
1.0E-04
0
20
40
60
80
100
Number of Charged Particles
Average PT versus Nchg
Average PT versus Nchg
0.7
CMS Preliminary
CMS 900 GeV <pT>=0.460
data corrected
generator level theory
pyZ1 NSD LHC09
pyZ1 LHC09 <pT>=0.489
<pT> increases by 20%
0.5
0.4
900 GeV
Average PT (GeV/c)
Average PT (GeV/c)
CMS Preliminary
0.6
0.7
CMS 900 GeV |eta| < 2.4
data corrected
generator level theory
0.6
0.5
0.4
CMS 7 TeV |eta| < 2.4
CMS 7 TeV <pT>=0.545
pyZ1 NSD LHC7
pyZ1 NSD LHC7 <pT>=0.577
7 TeV
Charged Particles (|h|<2.4, All pT)
Charged Particles (|h|<2.4, All pT)
0.3
0.3
0
10
20
30
40
50
60
70
80
0
90 100 110 120 130 140 150
10
20
30
40
50
60
70
80
90 100 110 120 130 140 150
Number of Charged Particles
Number of Charged Particles
Note that for a given multiplicity <pT> increase only very slightly with in
going from 900 GeV to 7 TeV (2%-4%). However, the average pT increases
by ~20% due mainly from the broadening of the multiplicity distribution!
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 26
Energy Dependence
Ratio: Average PT versus Nchg
Ratio: Average PT versus Nchg
1.3
CMS Preliminary
CMS Preliminary
Charged Particles (|h|<2.4, All pT)
data corrected
generator level theory
Ratio: 7 TeV / 900 GeV
Ratio: 7 TeV / 900 GeV
1.3
1.2
1.1
CMS Ratio |eta| < 2.4
1.0
CMS Ratio = 1.185
7 TeV / 900 GeV
5
10
15
20
Tune PQ20
1.1
1.0
7 TeV / 900 GeV
pyX1844 Ratio = 1.194
25
30
35
40
45
50
55
60
Tune P0
Tune P329
1.2
pyX1844_10mm NSD Ratio
0.9
0
data corrected
generator level theory
Charged Particles (|h|<2.4, All pT)
0.9
65
0
5
10
Overall average pTNumber of Charged Particles
15
20
25
30
35
40
45
50
55
60
65
Number of Charged Particles
 Shows the energy dependence of the CMS NSD corrected data on <pT> versus Nchg
(all pT, |h| < 2.4) compared with Tune X2. Also shows the energy dependence of the
overall <pT> compared with Tune X2.
 Shows the energy dependence of the CMS NSD corrected data on <pT> versus Nchg
(all pT, |h| < 2.4) compared with Tune P0, Tune PQ20, and Tune P329. It will be
interesting to see if any tune can get this right!
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 27
Energy Dependence
Ratio: Average PT versus Nchg
Ratio: 7 TeV / 900 GeV
1.3
Amazing!
CMS Preliminary
Charged Particles (|h|<2.4, All pT)
data corrected
generator level theory
1.2
1.1
CMS Ratio |eta| < 2.4
1.0
CMS Ratio = 1.185
7 TeV / 900 GeV
pyZ1 NSD Ratio
0.9
pyZ1 Ratio = 1.149
0
5
10
15
20
25
30
35
40
45
50
55
60
65
Number of Charged Particles
ATLAS AMBT1 probably
does well here also!
<pT> versus Nchg
 Shows the energy dependence of the CMS NSD corrected data on
(all pT, |h| < 2.4) compared with Tune Z1. Also shows the energy dependence of the
overall <pT> compared with Tune Z1.
“Minimum Bias” Collisions
Proton
MPI@LHC 2010
Glasgow, November 30, 2010
First Tune (except PhoJet)Proton
to come close here!
Rick Field – Florida/CDF/CMS
Page 28
MB & UE
"Transverse" Charged Particle Multiplicity
Charged Multiplicity Distribution
1.0E+00
1.0E-01
“Min-Bias”
RDF Preliminary
PT(chgjet#1) > 3 GeV/c
data CMS NSD
pyZ1 generator level
CMS
1.0E-02
Probability
Probability
data uncorrected
pyZ1 + SIM
1.0E-01
CMS
1.0E-02
CMS Preliminary
7 TeV
Tune Z1
1.0E-03
7 TeV
900 GeV
1.0E-04
900 GeV
1.0E-03
“Underlying Event”
1.0E-05
Normalized to 1
Charged Particles
(all PT, |h|<2.0)
1.0E-04
0
20
1.0E-06
Difficult to produce
40
60
80
enough
events
with
Number of Charged Particles
large multiplicity!
1.0E-07
0
100
 Generator level charged multiplicity
distribution (all pT, |h| < 2) at 900 GeV
and 7 TeV. Shows the NSD = HC + DD
prediction for Tune Z1. Also shows the
CMS NSD data.
MPI@LHC 2010
Glasgow, November 30, 2010
Charged Particles (|h|<2.0, PT>0.5 GeV/c)
Tune Z1
5
10
15
20
25
30
35
40
Number of Charged Particles
 CMS uncorrected
Difficult
datatoatproduce
900 GeV and 7
TeV on the charged
enoughparticle
events with
multiplicity
distribution inlarge
the “transverse”
“transverse” region
for charged particles
multiplicity
(pT >at0.5
low
GeV/c, |h|
< 2) as defined byhard
the leading
scale! charged
particle jet with PT(chgjet#1) > 3 GeV/c
compared with PYTHIA Tune Z1 at the
detector level (i.e. Theory + SIM).
Rick Field – Florida/CDF/CMS
Page 29
MB & UE
ChargedParticle
ParticleMultiplicity
Multiplicity
Charged
1.0E+00
1.0E+00
CMS
TeV
77 TeV
CMS Preliminary
Preliminary
CMS
Tune Z1
Z1
Tune
Min-Bias
NSD All pT
1.0E-01
1.0E-01
Probability
Probability
Min-Bias
NSD All pT
1.0E-02
1.0E-02
Underlying Event
"Transverse" Region
pT > 0.5 GeV/c
PT(chgjet#1) > 20 GeV/c
1.0E-03
1.0E-03
1.0E-04
1.0E-04
Normalizedto
to11
Normalized
Underlying Event
"Transverse" Region
pT > 0.5 GeV/c
PT(chgjet#1) > 20 GeV/c
Tune Z1
Charged Particles (|h|<2.0)
Charged Particles (|h|<2.0)
1.0E-05
1.0E-05
00
5
2010
1540
20
60
25
30 80 35
100
40
Number of
of Charged
Charged Particles
Particles
Number
 CMS uncorrected data at 7 TeV on the charged particle multiplicity distribution in the
“transverse” region for charged particles (pT > 0.5 GeV/c, |h| < 2) as defined by the leading
charged particle jet with PT(chgjet#1) > 20 GeV/c compared with PYTHIA Tune Z1 at the
detector level (i.e. Theory + SIM). Also shows the CMS corrected NSD multiplicity
distribution (all pT, |h| < 2) compared with Tune Z1 at the generator.
Amazing what we are asking the Monte-Carlo models to fit!
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 30
Strange Particle Production
Factor of 2!
ALICE preliminary
stat. error only
Phojet
Pythia ATLAS-CSC
Pythia D6T
Pythia Perugia-0
 A lot more strange mesons at large pT than predicted by the Monte-Carlo
Models!
 K/p ratio fairly independent of the center-of-mass energy.
MPI@LHC 2010
Glasgow, November 30, 2010
Rick Field – Florida/CDF/CMS
Page 31
The LHC in 2011
 Beam back around 21st February.
 Beam back around on February 21st!
 2 weeks re-commissioning with beam (at
least).
technical stop every 6 weeks.
Thisis4 day
fun!
 4 weeks ion run.
 End of run – December 12th.
 Approximately 200 days proton physics!
 Maybe 8 TeV (4 TeV/beam).
Peak luminosity
MPI@LHC 2010
Glasgow, November 30, 2010
6.4 x 1032
Integrated per day
11 pb-1
200 days
2.2 fb-1
Stored energy
72 MJ
Rick Field – Florida/CDF/CMS
Page 32