51 st Cracow School of Theoretical Physics The Soft Side of the LHC
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Transcript of 51 st Cracow School of Theoretical Physics The Soft Side of the LHC
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 1
5151stst Cracow School of Theoretical Physics Cracow School of Theoretical PhysicsThe Soft Side of the LHCThe Soft Side of the LHC
Proton Proton
“Minimum Bias” Collisions
Rick FieldUniversity of Florida
UE&MB@CMSUE&MB@CMS
Lecture 2: Outline
CMS
ATLAS
Zakopane, Poland, June 11-19, 2011
Min-Bias and the Underlying Event at the LHC
How are “min-bias” collisions related to the “underlying event”.
How well did we do at predicting the behavior of “min-bias” collisions at the LHC (900 GeV and 7 TeV)?
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
Baryon and Strange Particle Production at the LHC: Fragmentation tuning.
K+
u s K-
u s
Kshort
d s s d +
p
u u d
u d s
d s s
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 2
Toward an Understanding ofToward an Understanding ofHadron-Hadron CollisionsHadron-Hadron Collisions
Rick FieldUniversity of Florida
From Feynman-Field to the LHC
Lecture 3: Tomorrow Evening
The early days of Feynman-Field Phenomenology.
Before Feynman-Field Phenomenology: The Berkeley years.
From 7 GeV/c 0’s to 1 TeV Jets!
Feynman
Field
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 3
Proton-Proton CollisionsProton-Proton Collisions Elastic Scattering Single Diffraction
M
tot = ELSD DD HC
Double Diffraction
M1 M2
Proton Proton
“Soft” Hard Core (no hard scattering)
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
“Hard” Hard Core (hard scattering)
Hard Core The “hard core” component
contains both “hard” and “soft” collisions.
“Inelastic Non-Diffractive Component”
NDtot = ELIN
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 4
The Inelastic Non-Diffractive The Inelastic Non-Diffractive Cross-SectionCross-Section
Proton Proton
Proton Proton +
Proton Proton
Proton Proton
+
Proton Proton +
+ …
“Semi-hard” parton-parton collision(pT < ≈2 GeV/c)
Occasionally one of the parton-parton collisions is hard(pT > ≈2 GeV/c)
Majority of “min-bias” events!
Multiple-parton interactions (MPI)!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 5
The “Underlying Event”The “Underlying Event”
Proton Proton
Select inelastic non-diffractive events that contain a hard scattering
Proton Proton
Proton Proton +
Proton Proton
+ + …
“Semi-hard” parton-parton collision(pT < ≈2 GeV/c)
Hard parton-parton collisions is hard(pT > ≈2 GeV/c) The “underlying-event” (UE)!
Multiple-parton interactions (MPI)!
Given that you have one hard scattering it is more probable to have MPI! Hence, the UE has more activity than “min-bias”.
1/(pT)4→ 1/(pT2+pT0
2)2
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 6
Model of Model of NDND
Proton Proton
Proton Proton +
Proton Proton
Proton Proton
+
Proton Proton +
+ …
“Semi-hard” parton-parton collision(pT < ≈2 GeV/c)
Allow leading hard scattering to go to zero pT with same cut-off as the MPI!
Model of the inelastic non-diffractive cross section!
Multiple-parton interactions (MPI)!
Proton Proton
1/(pT)4→ 1/(pT2+pT0
2)2
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 7
UE TunesUE Tunes
Proton Proton
Proton Proton +
Proton Proton
Proton Proton
+
Proton Proton +
+ …
“Underlying Event”
“Min-Bias” (ND)
Fit the “underlying event” in a hard
scattering process.
Predict MB (ND)!
1/(pT)4→ 1/(pT2+pT0
2)2
Allow primary hard-scattering to go to pT = 0 with same cut-off!
Single Diffraction
M
Double Diffraction
M1 M2
“Min-Bias” (add single & double diffraction)
Predict MB (IN)!
All of Rick’s tunes (except X2):A, AW, AWT,DW, DWT,
D6, D6T, CW, X1, and Tune Z1,are UE tunes!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 8
Charged Particle MultiplicityCharged Particle Multiplicity
Data at 1.96 TeV on the charged particle multiplicity (pT > 0.4 GeV/c, || < 1) for “min-bias” collisions at CDF Run 2 (non-diffractive cross-section).
Charged Multiplicity Distribution
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
0 5 10 15 20 25 30 35 40 45 50 55
Number of Charged Particles
Pro
ba
bil
ity
CDF Run 2 <Nchg>=4.5
Normalized to 1
CDF Run 2 Preliminary
Min-Bias 1.96
Charged Particles (||<1.0, PT>0.4 GeV/c)
i
Proton AntiProton
“Minimum Bias” Collisions
The data are compared with PYTHIA Tune A and Tune A without multiple parton interactions (pyAnoMPI).
Charged Multiplicity Distribution
1.0E-08
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
0 5 10 15 20 25 30 35 40 45 50 55
Number of Charged Particles
Pro
bab
ility
CDF Run 2 <Nchg>=4.5
py Tune A <Nchg> = 4.3
pyAnoMPI <Nchg> = 2.6
Charged Particles (||<1.0, PT>0.4 GeV/c)
CDF Run 2 Preliminary
Min-Bias 1.96 Normalized to 1
No MPI! Tune A!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 9
PYTHIA Tune A Min-BiasPYTHIA Tune A Min-Bias“Soft” + ”Hard”“Soft” + ”Hard”
Comparison of PYTHIA Tune A with the pT distribution of charged particles for “min-bias” collisions at CDF Run 1 (non-diffractive cross-section).
Charged Particle Density
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
0 2 4 6 8 10 12 14
PT(charged) (GeV/c)
Ch
arg
ed D
ensi
ty d
N/d
df d
PT
(1/
GeV
/c)
Pythia 6.206 Set A
CDF Min-Bias Data
CDF Preliminary
1.8 TeV ||<1
PT(hard) > 0 GeV/c12% of “Min-Bias” events have PT(hard) > 5 GeV/c!
1% of “Min-Bias” events have PT(hard) > 10 GeV/c!
PYTHIA Tune A predicts that 12% of all “Min-Bias” events are a result of a hard 2-to-2 parton-parton scattering with PT(hard) > 5 GeV/c (1% with PT(hard) > 10 GeV/c)!
Lots of “hard” scattering in “Min-Bias” at the Tevatron!
Ten decades!
pT = 50 GeV/c!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 10
MB TunesMB Tunes
Proton Proton +
Proton Proton
Proton Proton
+
Proton Proton +
+ …
“Underlying Event”
“Min-Bias” (ND)
Predict the “underlying event” in a hard
scattering process!
Fit MB (ND).
Proton Proton
Most of Peter Skand’s tunes:S320 Perugia 0, S325 Perugia X,
S326 Perugia 6are MB tunes!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 11
MB+UE TunesMB+UE Tunes
Proton Proton
Proton Proton +
Proton Proton
Proton Proton
+
Proton Proton +
+ …
“Underlying Event”
“Min-Bias” (ND)
Fit the “underlying event” in a hard
scattering process!
Fit MB (ND).
Most of Hendrik’s “Professor” tunes: ProQ20, P329
are MB+UE!
The ATLAS AMBT1 Tune is an MB+UE tune, butbecause they include in the fit the ATLAS UE data
with PTmax > 10 GeV/c (big errors) the LHC UE datadoes not have much pull (hence mostly an MB tune!).
Simultaneous fit to both MB & UE
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 12
LHC MB Predictions: 900 GeVLHC MB Predictions: 900 GeV
Proton Proton
“Minimum Bias” Collisions
Compares the 900 GeV ALICE data with PYTHIA Tune DW and Tune S320 Perugia 0. Tune DW uses the old Q2-ordered parton shower and the old MPI model. Tune S320 uses the new pT-ordered parton shower and the new MPI model. The numbers in parentheses are the average value of dN/d for the region || < 0.6.
Proton Proton
“Minimum Bias” Collisions
Charged Particle Density: dN/d
0
1
2
3
4
5
-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
Par
ticl
e D
en
sit
y
ALICE INEL
UA5 INEL
pyDW INEL (2.67)
pyS320 INEL (2.70)
RDF Preliminary
INEL = HC+DD+SD 900 GeV
Charged Particles (all pT)
Charged Particle Density: dN/d
0
1
2
3
4
5
-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
Par
ticl
e D
en
sit
y
UA5
ALICE
pyDW_10mm (3.04)
pyS320_10mm (3.09)
NSD = HC+DD 900 GeV
RDF Preliminary
Charged Particle Density: dN/d
0
1
2
3
4
5
-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
Par
ticl
e D
en
sit
y
ALICE INELUA5 INELpyDW times 1.11 (2.97)pyS320 times 1.11 (3.00)
RDF Preliminary
INEL = HC+DD+SD 900 GeV
times 1.11
Charged Particles (all pT)
Off by 11%!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 13
ATLAS INEL dN/dATLAS INEL dN/d
Soft particles!
None of the tunes fit the ATLAS INEL dN/d data with PT > 100 MeV! They all predict too few particles.
The ATLAS Tune AMBT1 was designed to fit the inelastic data for Nchg ≥ 6 with pT > 0.5 GeV/c!
Off by 20-50%!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 14
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
Par
ticl
e D
ens
ity
7 TeV
RDF PreliminaryCMS NSD data
pyDW generator level
dashed = ND solid = NSD
CMS dN/dCMS dN/d
Generator level dN/d (all pT). Shows the NSD = HC + DD and the HC = ND contributions for Tune DW. Also shows the CMS NSD data.
CMS
Tune DW
All pT
Soft particles!
Proton Proton
“Minimum Bias” Collisions
Off by 50%!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 15
PYTHIA Tune DWPYTHIA Tune DWCharged Particle Density: dN/d
0
1
2
3
4
5
-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0
PseudoRapidity
Ch
arg
ed
Par
ticl
e D
ens
ity
900 GeV
pT > 0.15 GeV/c
RDF PreliminaryALICE INEL data
pyDW generator level
pT > 0.5 GeV/c
pT > 1.0 GeV/c
At Least 1 Charged Particle || < 0.8
ALICE inelastic data at 900 GeV on the dN/d distribution for charged particles (pT > PTmin) for events with at least one charged particle with pT > PTmin and || < 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.
If one increases the pT the agreement
improves!
Tune DW
Proton Proton
“Minimum Bias” Collisions
The same thing occurs at 7 TeV! ALICE, ATLAS, and CMS data coming soon.
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 16
PYTHIA Tune DWPYTHIA Tune DW
ALICE inelastic data at 900 GeV on the dN/d distribution for charged particles (pT > PTmin) for events with at least one charged particle with pT > PTmin and || < 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).
Charged Particle Density: dN/d
0
1
2
3
4
5
-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0
PseudoRapidity
Ch
arg
ed
Par
ticl
e D
ens
ity
900 GeV
pT > 0.15 GeV/c
RDF PreliminaryALICE INEL data
pyDW generator level
pT > 0.5 GeV/c
pT > 1.0 GeV/c
dashed = ND solid = INEL
At Least 1 Charged Particle || < 0.8
Diffraction contributes less at
harder scales!
Tune DW
Proton Proton
“Minimum Bias” Collisions
Cannot trust PYTHIA 6.2 modeling of diffraction!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 17
Min-Bias CollisionsMin-Bias Collisions
CMS NSD data on the charged particle rapidity distribution at 7 TeV compared with PYTHIA Tune Z1. The plot shows the average number of particles per NSD collision per unit , (1/NNSD) dN/d.
CMS
Proton Proton
“Minimum Bias” Collisions
Okay not perfect, but remember we know that SD and DD are not modeled well!
Charged Particle Density: dN/d
0
2
4
6
8
-4 -3 -2 -1 0 1 2 3 4
Pseudo-Rapidity
Ch
arg
ed P
arti
cle
De
ns
ity
pyZ1 ND = dashed
pyZ1 NSD = solid
CMS DataPYTHIA Tune Z1
NSD (all pT) 7 TeV
ALICE NSD data on the charged particle rapidity distribution at 900 GeV compared with PYTHIA Tune Z1. The plot shows the average number of particles per INEL collision per unit , (1/NINEL) dN/d.
Tune Z1
Charged Particle Density: dN/d
0
2
4
6
-4 -3 -2 -1 0 1 2 3 4
Pseudo-Rapidity
Ch
arg
ed
Par
ticl
e D
en
sit
y
pyZ1 NSD = dashed
pyZ1 INEL = solid
ALICE DataPYTHIA Tune Z1
INEL (all pT) 900 GeV
Tune Z1
ALICE
NSD = ND + DD
INEL = NSD + SD
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 18
PYTHIA Tune Z1PYTHIA Tune Z1
ALICE inelastic data at 900 GeV on the dN/d distribution for charged particles (pT > PTmin) for events with at least one charged particle with pT > PTmin and || < 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.
Charged Particle Density: dN/d
0
1
2
3
4
5
-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0
PseudoRapidity
Ch
arg
ed
Par
ticl
e D
ens
ity
900 GeV
pT > 0.15 GeV/c
RDF PreliminaryALICE INEL data
pyZ1 generator level
pT > 0.5 GeV/c
pT > 1.0 GeV/c
At Least 1 Charged Particle || < 0.8
Proton Proton
“Minumum Bias” Collisions
Okay not perfect, but remember we do not know if the SD & DD are correct!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 19
NSD Multiplicity DistributionNSD Multiplicity Distribution
Generator level charged multiplicity distribution (all pT, || < 2) at 900 GeV and 7 TeV. Shows the NSD = HC + DD prediction for Tune Z1. Also shows the CMS NSD data.
Charged Multiplicity Distribution
1.0E-04
1.0E-03
1.0E-02
1.0E-01
0 20 40 60 80 100
Number of Charged Particles
Pro
ba
bil
ity
Charged Particles (all PT, ||<2.0)
RDF Preliminarydata CMS NSD
pyZ1 generator level
7 TeV
900 GeV
CMS
Tune Z1
Difficult to produce enough events with large multiplicity!
Proton Proton
“Minumum Bias” Collisions
Okay not perfect!But not that bad!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 20
MB versus UEMB versus UE
CMS NSD data on the charged particle rapidity distribution at 7 TeV compared with PYTHIA Tune Z1. The plot shows the average number of charged particles per NSD collision per unit , (1/NNSD) dN/d.
CMS
Proton Proton
“Minimum Bias” Collisions
Charged Particle Density: dN/d
0
2
4
6
8
-4 -3 -2 -1 0 1 2 3 4
Pseudo-Rapidity
Ch
arg
ed P
arti
cle
De
ns
ity
pyZ1 ND = dashed
pyZ1 NSD = solid
CMS DataPYTHIA Tune Z1
NSD (all pT) 7 TeV
Tune Z1
NSD = ND + DD
CMS NSD data on the charged particle rapidity distribution at 7 TeV compared with PYTHIA Tune Z1. The plot shows the average number of charged particles per NSD collision per unit f, (1/NNSD) dN/ddf.
Charged Particle Density: dN/ddf
0.0
0.5
1.0
1.5
2.0
2.5
-4 -3 -2 -1 0 1 2 3 4
Pseudo-Rapidity
Ch
arg
ed
Par
ticl
e D
en
sit
y
pyZ1 ND = dashed
pyZ1 NSD = solid
CMS DataPYTHIA Tune Z1
NSD (all pT) 7 TeV
Divide be 2
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 21
MB versus UEMB versus UE
Proton Proton
“Minimum Bias” Collisions
CMSTune Z1 NSD = ND + DD
CMS NSD data on the charged particle rapidity distribution at 7 TeV compared with PYTHIA Tune Z1. The plot shows the average number of charged particles per NSD collision per unit f, (1/NNSD) dN/ddf.
Charged Particle Density: dN/ddf
0.0
0.5
1.0
1.5
2.0
2.5
-4 -3 -2 -1 0 1 2 3 4
Pseudo-Rapidity
Ch
arg
ed
Par
ticl
e D
en
sit
y
pyZ1 ND = dashed
pyZ1 NSD = solid
CMS DataPYTHIA Tune Z1
NSD (all pT) 7 TeV
Transverse Charged Particle Density: dN/ddf
0.0
0.5
1.0
1.5
2.0
2.5
0 5 10 15 20 25
PT max (GeV/c)
Ch
arg
ed P
arti
cle
De
nsi
ty
7 TeV ND
Charged Particles (|| < 2, all pT)
RDF PreliminaryPYTHIA Tune Z1
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
Shows the density of charged particles in the “transverse” region as a function of PTmax for charged particles (All pT, || < 2) at 7 TeV from PYTHIA Tune Z1.
Tune Z1
Factor of 2!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 22
MB versus UEMB versus UE
Proton Proton
“Minimum Bias” Collisions
CMSTune Z1 NSD = ND + DD
CMS NSD data on the charged particle rapidity distribution at 7 TeV compared with PYTHIA Tune Z1. The plot shows the average number of charged particles per NSD collision per unit f, (1/NNSD) dN/ddf.
Charged Particle Density: dN/ddf
0.0
0.5
1.0
1.5
2.0
2.5
-4 -3 -2 -1 0 1 2 3 4
Pseudo-Rapidity
Ch
arg
ed
Par
ticl
e D
en
sit
y
pyZ1 ND = dashed
pyZ1 NSD = solid
CMS DataPYTHIA Tune Z1
NSD (all pT) 7 TeV
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
ATLAS data on the density of charged particles in the “transverse” region as a function of PTmax for charged particles (pT > 0.1 GeV/c, || < 2.5) at 7 TeV compared with PYTHIA Tune Z1.
Factor of 2!
"Transverse" Charged Particle Density: dN/ddf
0.0
0.5
1.0
1.5
2.0
2.5
0 2 4 6 8 10 12 14 16 18 20
PTmax (GeV/c)
"Tra
nsv
erse
" C
har
ged
Den
sity
RDF PreliminaryATLAS corrected data
Tune Z1 generator level
7 TeV Charged Particles (pT > 0.1 GeV/c, ||<2.5)
ATLAS
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 23
Baryon & Strange Particle Baryon & Strange Particle Production at the LHCProduction at the LHC
Strange Particle Production in Proton-Proton Collisions at 900 GeV with ALICE at the LHC, arXiv:1012.3257 [hep-ex] December 18, 2010.
Production of Pions, Kaons and Protons in pp Collisions at 900 GeV with ALICE at the LHC, arXiv:1101.4110 [hep-ex] January 25, 2011.
Strange Particle Production in pp Collisions at 900 GeV and 7 TeV, CMS Paper: arXiv:1102.4282 [hep-ex] Feb 21, 2011, submitted to JHEP.
Step 1: Look at the overall particle yields (all pT). K+
u s
K-
u s
Kshort
d s s d +
p
u u d
u d s
d s s
Step 2: Look at the ratios of the overall particle yields (all pT).
Step 3: Look at the pT dependence of the particle yields and ratios.
I know there are more nice results
from the LHC, but this is all I can show
today. Sorry!
INEL
INEL
NSD
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 24
Kaon ProductionKaon Production
CMS NSD data on the Kshort rapidity distribution at 7 TeV and 900 GeV compared with PYTHIA Tune Z1. The plot shows the average number of Kshort per NSD collision per unit Y, (1/NNSD) dN/dY.
Kshort Rapidity Distribution: dN/dY
0.0
0.1
0.2
0.3
0.4
0.5
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
CMS DataPYTHIA Tune Z1
900 GeV
7 TeV
NSD (all pT) Tune Z1
CMS
Kshort Rapidity Distribution: dN/dY
0.0
0.1
0.2
0.3
0.4
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY 900 GeV
CMS & ALICE DataPYTHIA Tune Z1
CMS NSD
ALICE INEL pyZ1 NSD = solid
pyZ1 INEL = dashed
CMS NSD data on the Kshort rapidity distribution at 900 GeV and the ALICE point at Y = 0 (INEL) compared with PYTHIA Tune Z1. The ALICE point is the average number of Kshort per INEL collision per unit Y at Y = 0, (1/NINEL) dN/dY.
Tune Z1
INEL = NSD + SD
Proton Proton
“Minimum Bias” Collisions
No overall shortage of Kaons in PYTHIA Tune Z1!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 25
Kaon ProductionKaon Production
ALICE INEL data on the charged kaon rapidity distribution at 900 GeV compared with PYTHIA Tune Z1. The plot shows the average number of charged kaons per INEL collision per unit Y at Y = 0, (1/NINEL) dN/dY.
Proton Proton
“Minimum Bias” Collisions
Charged Kaons Rapidity: dN/dY
0.0
0.2
0.4
0.6
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
ALICE DataPYTHIA Tune Z1
INEL (all pT) 900 GeVpyZ1 NSD = dashed
pyZ1 INEL = solid
(K++K-)
Rapidity Distribution Ratio: Kaons/Pions
0.0
0.1
0.2
0.3
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
ticl
e R
ati
o
ALICE DataPYTHIA Tune Z1
INEL (all pT) 900 GeV
(K++K-)/(++-)
ALICE INEL data on the charged kaon to charged pion rapidity ratio at 900 GeV compared with PYTHIA Tune Z1.
ALICE ALICE
Tune Z1 Tune Z1
Rapidity Distribution Ratio: Kshort/Kaons
0.0
0.2
0.4
0.6
0.8
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
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ALICE DataPYTHIA Tune Z1
INEL (all pT) 900 GeV
Kshort/(K++K-)
No overall shortage of Kaons in PYTHIA Tune Z1!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 26
Kaon ProductionKaon Production
Rick’s plot of the CMS NSD data on the Kshort rapidity distribution at 7 TeV and 900 GeV. The plot shows the average number of Kshort per NSD collision per unit Y, (1/NNSD) dN/dY, versus Y from -2 → 2.
CMS measures (1/NNSD) dN/dY
Real CMS NSD data on the Kshort rapidity distribution at 7 TeV and 900 GeV. The plot shows the average number of Kshort per NSD collision per unit Y, (1/NNSD) dN/dY, versus |Y| from 0 → 2.
Kshort Rapidity Distribution: dN/dY
0.0
0.1
0.2
0.3
0.4
0.5
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
CMS DataPYTHIA Tune Z1
900 GeV
7 TeV
NSD (all pT)
versus |Y| from 0 → 2
I am old and I like to see both sides so I assumed symmetry about Y = 0 and plotted the same data on both sides (Y → -Y). The way CMS does it is the correct way! But my way helps me see better what is going on. Please refer to the CMS publication for the official plots!
Warning: I am not plotting what CMS actually measures!
This is the correct way!
I have plotted the same data twice!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 27
Lambda ProductionLambda Production
CMS NSD data on the Lambda+AntiLambda rapidity distribution at 7 TeV and 900 GeV compared with PYTHIA Tune Z1. The plot shows the average number of particles per NSD collision per unit Y, (1/NNSD) dN/dY.
Proton Proton
“Minimum Bias” Collisions
(Lam+LamBar) Rapidity Distribution: dN/dY
0.00
0.05
0.10
0.15
0.20
0.25
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
CMS DataPYTHIA Tune Z1
900 GeV
7 TeV
NSD (all pT)
(+)_
Rapidity Distribution Ratio: (Lam+LamBar)/(2Kshort)
0.0
0.1
0.2
0.3
0.4
0.5
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
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CMS DataPYTHIA Tune Z1
7 TeV
NSD (all pT)
(+)/(2Kshort)_
CMS Tune Z1
CMS NSD data on the Lambda+AntiLambda to 2Kshort rapidity ratio at 7 TeV compared with PYTHIA Tune Z1.
CMS
Tune Z1
Factor of 1.5!
Oops! Not enough Lambda’s in PYTHIA Tune Z1!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 28
Cascade ProductionCascade Production
CMS NSD data on the Cascade-+AntiCascade- rapidity distribution at 7 TeV and 900 GeV compared with PYTHIA Tune Z1. The plot shows the average number of particles per NSD collision per unit Y, (1/NNSD) dN/dY.
Proton Proton
“Minimum Bias” Collisions
(Cas+CasBar) Rapidity Distribution: dN/dY
0.00
0.01
0.02
0.03
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
CMS DataPYTHIA Tune Z1
900 GeV
7 TeV
NSD (all pT)
(+
)_
Rapidity Distribution Ratio: (Cas+CasBar)/(2Kshort)
0.00
0.01
0.02
0.03
0.04
0.05
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
ticl
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CMS DataPYTHIA Tune Z1
7 TeV
NSD (all pT)
(+
)/(2Kshort)_
CMS
Tune Z1
CMS data on the Cascade-+AntiCascade- to 2Kshort rapidity ratio at 7 TeV compared with PYTHIA Tune Z1.
CMS
Tune Z1
Factor of 2!
Yikes! Way too few Cascade’s in PYTHIA Tune Z1!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 29
PYTHIA Fragmentation PYTHIA Fragmentation ParametersParameters
PARJ(1) : (D = 0.10) is P(qq)/P(q), the suppression of diquark-antidiquark pair production in the colour field, compared with quark–antiquark production. Notation: PARJ(1) = qq/q
PARJ(2) : (D = 0.30) is P(s)/P(u), the suppression of s quark pair production in the field compared with u or d pair production. Notation: PARJ(2) = s/u.
PARJ(3) : (D = 0.4) is (P(us)/P(ud))/(P(s)/P(u)), the extra suppression of strange diquark production compared with the normal suppression of strange quarks. Notation: PARJ(3) = us/u .
Can we increase the overall rate of strange baryons by varying a few fragmentation parameters?
This work is very preliminary!
Warning! This may cause problemsfitting the LEP data. If sowe must understand why!
We do not want one tune for e+e- and another one for
hadron-hadron collisions!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 30
PYTHIA Fragmentation PYTHIA Fragmentation ParametersParameters
PYTHIA Tune Z1C: Same as Tune Z1 except qq/q is increased 0.1 → 0.12 and us/s is increased from 0.4 → 0.8.
Rapidity Distribution Ratio: (Lam+LamBar)/(2Kshort)
0.0
0.1
0.2
0.3
0.4
0.5
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
ticl
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CMS DataPYTHIA Tune Z1
7 TeVNSD (all pT) s/u: 0.3 -> 0.5
us/s: 0.4 -> 1.0
qq/q: 0.1 -> 0.2
Z1 default
(+)/(2Kshort)_
Rapidity Distribution Ratio: (Cas+CasBar)/(2Kshort)
0.00
0.01
0.02
0.03
0.04
0.05
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
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CMS DataPYTHIA Tune Z1
7 TeVNSD (all pT)
s/u: 0.3 -> 0.5
us/s: 0.4 -> 1.0qq/q: 0.1 -> 0.2
Z1 default
(+
)/(2Kshort)_
Rapidity Distribution Ratio: Kaons/Pions
0.0
0.1
0.2
0.3
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
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ati
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ALICE DataPYTHIA Tune Z1
INEL (all pT) 900 GeV
(K++K-)/(++-)s/u: 0.3 -> 0.5
us/s: 0.4 -> 1.0
qq/q: 0.1 -> 0.2Z1 default
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 31
Kaon ProductionKaon Production
CMS NSD data on the Kshort rapidity distribution at 7 TeV and 900 GeV compared with PYTHIA Tune Z1. The plot shows the average number of Kshort per NSD collision per unit Y, (1/NNSD) dN/dY.
Kshort Rapidity Distribution: dN/dY
0.0
0.1
0.2
0.3
0.4
0.5
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
CMS DataPYTHIA Tune Z1
900 GeV
7 TeV
NSD (all pT) Tune Z1CMS
Kshort Rapidity Distribution: dN/dY
0.0
0.1
0.2
0.3
0.4
0.5
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
Ch
arg
ed
Par
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ati
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CMS DataPYTHIA Tune Z1C
900 GeV
7 TeV
NSD (all pT)
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
CMS dNSD ata on the Kshort rapidity distribution at 7 TeV and 900 GeV compared with PYTHIA Tune Z1C. The plot shows the average number of Kshort per NSD collision per unit Y, (1/NNSD) dN/dY.
Tune Z1CCMS
Rapidity Distribution Ratio: Kaons/Pions
0.0
0.1
0.2
0.3
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
ticl
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ati
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ALICE DataPYTHIA Tune Z1 & Z1C
INEL (all pT) 900 GeV
(K++K-)/(++-)
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
Proton Proton
“Minimum Bias” Collisions
For Kaon production Tune Z1 and Z1C are almost identical!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 32
Lambda ProductionLambda Production
CMS NSD data on the Lambda+AntiLambda rapidity distribution at 7 TeV and 900 GeV compared with PYTHIA Tune Z1. The plot shows the average number of particles per NSD collision per unit Y, (1/NNSD) dN/dY.
(Lam+LamBar) Rapidity Distribution: dN/dY
0.00
0.05
0.10
0.15
0.20
0.25
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
CMS DataPYTHIA Tune Z1
900 GeV
7 TeV
NSD (all pT)
(+)_
(Lam+LamBar) Rapidity Distribution: dN/dY
0.00
0.05
0.10
0.15
0.20
0.25
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
Ch
arg
ed
Par
ticl
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ati
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CMS DataPYTHIA Tune Z1C
900 GeV
7 TeV
NSD (all pT)
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
(+)_
CMS NSD data on the Lambda+AntiLambda rapidity distribution at 7 TeV and 900 GeV compared with PYTHIA Tune Z1. The plot shows the average number of particles per NSD collision per unit Y, (1/NNSD) dN/dY.
CMS Tune Z1
CMS
Tune Z1C
Rapidity Distribution Ratio: (Lam+LamBar)/(2Kshort)
0.0
0.1
0.2
0.3
0.4
0.5
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
ticl
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ati
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CMS DataPYTHIA Tune Z1 & Z1C
7 TeV
NSD (all pT)
(+)/(2Kshort)_
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
Proton Proton
“Minimum Bias” Collisions
Not bad! Many more Lambda’s in PYTHIA Tune Z1C!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 33
Cascade ProductionCascade Production
CMS NSD data on the Cascade-+AntiCascade- rapidity distribution at 7 TeV and 900 GeV compared with PYTHIA Tune Z1. The plot shows the average number of particles per NSD collision per unit Y, (1/NNSD) dN/dY.
(Cas+CasBar) Rapidity Distribution: dN/dY
0.00
0.01
0.02
0.03
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
CMS DataPYTHIA Tune Z1
900 GeV
7 TeV
NSD (all pT)
(+
)_
(Cas+CasBar) Rapidity Distribution: dN/dY
0.00
0.01
0.02
0.03
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
Ch
arg
ed
Par
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ati
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CMS DataPYTHIA Tune Z1C
900 GeV
7 TeV
NSD (all pT)
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
(+
)_
CMS
Tune Z1
CMS
Tune Z1C
Rapidity Distribution Ratio: (Cas+CasBar)/(2Kshort)
0.00
0.01
0.02
0.03
0.04
0.05
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
ticl
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ati
o
7 TeV
NSD (all pT)
CMS DataPYTHIA Tune Z1 & Z1C
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
(+
)/(2Kshort)_
CMS NSD data on the Cascade-+AntiCascade- rapidity distribution at 7 TeV and 900 GeV compared with PYTHIA Tune Z1. The plot shows the average number of particles per NSD collision per unit Y, (1/NNSD) dN/dY.
Rapidity Ratio: (Cas+CasBar)/(Lam+LamBar)
0.00
0.05
0.10
0.15
0.20
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
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ati
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7 TeV
NSD (all pT)
CMS DataPYTHIA Tune Z1 & Z1C
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
(+
)/(+)_ _
Proton Proton
“Minimum Bias” Collisions
Wow! PYTHIA Tune Z1C looks very nice here!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 34
Transverse Momentum Transverse Momentum DistributionsDistributions
CMS NSD data on the Kshort transverse momentum distribution at 7 TeV compared with PYTHIA Tune Z1 & Z1C. The plot shows the average number of particles per NSD collision per unit pT, (1/NNSD) dN/dpT for |Y| < 2.
PT Distribution: Kshort
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
0 1 2 3 4 5 6 7 8 9 10
PT (GeV/c)
dN
/dP
T (
1/G
eV/c
)
CMS DataPYTHIA Tune Z1 & Z1C
NSD (|Y| < 2)) Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
7 TeV
PT Distribution: Lam+LamBar
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
0 1 2 3 4 5 6 7 8 9 10
PT (GeV/c)
dN
/dP
T (
GeV
/c)
CMS DataPYTHIA Tune Z1 & Z1C
NSD (|Y| < 2))
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
7 TeV
(+)_
CMS NSD data on the Lambda+AntiLambda transverse momentum distribution at 7 TeV compared with PYTHIA Tune Z1 & Z1C. The plot shows the average number of particles per NSD collision per unit pT, (1/NNSD) dN/dpT for |Y| < 2.
Proton Proton
“Minimum Bias” Collisions
PYTHIA Tune Z1 & Z1C are a bit off on the pT dependence!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 35
Transverse Momentum Transverse Momentum DistributionsDistributions
PT Distribution: Cas+CasBar
1.0E-04
1.0E-03
1.0E-02
1.0E-01
0 1 2 3 4 5 6 7
PT (GeV/c)
dN
/dP
T (
1/G
eV/c
)
CMS DataPYTHIA Tune Z1 & Z1C
NSD (|Y| < 2))
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
7 TeV
(+
)_
Cas+CasBar PT Distribution: dN/dPT
1.0E-03
1.0E-02
1.0E-01
1.0E+00
0 1 2 3 4 5 6 7
PT (GeV/c)
Pro
ba
bil
ity
CMS DataPYTHIA Tune Z1 & Z1C
NSD (|Y| < 2))
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
7 TeV
(+
)_
Normalized to 1
CMS NSD data on the Cascade-+AntiCascade- transverse momentum distribution at 7 TeV compared with PYTHIA Tune Z1 & Z1C. The plot shows the average number of particles per NSD collision per unit pT, (1/NNSD) dN/dpT for |Y| < 2.
CMS NSD data on the Cascade-+AntiCascade- transverse momentum distribution at 7 TeV (normalized to 1) compared with PYTHIA Tune Z1 & Z1C.
Proton Proton
“Minimum Bias” Collisions
PYTHIA Tune Z1 & Z1C are a bit off on the pT dependence!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 36
Particle Ratios versus PTParticle Ratios versus PT
Proton Proton
“Minimum Bias” Collisions
PT Particle Ratio: (Lam+LamBar)/(2Kshort)
0.0
0.2
0.4
0.6
0.8
0 1 2 3 4 5 6 7 8 9 10
PT (GeV/c)
PT
Par
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Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
7 TeVNSD (|Y| < 2)
CMS DataPYTHIA Tune Z1 & Z1C (+)/(2Kshort)
_
Particle Ratio: (Lam+LamBar)/(2Kshort)
0.0
0.2
0.4
0.6
0.8
0 1 2 3 4 5 6
PT (GeV/c)
Rat
io
ALICE DataPYTHIA Tune Z1 & Z1C
INEL (|Y| < 0.75) 900 GeV
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
(+)/(2Kshort)_
CMS NSD data on the Lambda+AntiLambda to 2Kshort ratio versus pT at 7 TeV (|Y| < 2) compared with PYTHIA Tune Z1 & Z1C.
ALICE INEL data on the Lambda+AntiLambda to 2Kshort ratio versus pT at 900 GeV (|Y| < 0.75) compared with PYTHIA Tune Z1 & Z1C.
Tune Z1C is not too bad but a bit off on the pT dependence!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 37
Particle Ratios versus PTParticle Ratios versus PT
Proton Proton
“Minimum Bias” Collisions
PT Particle Ratio: (Cas+CasBar)/(2Kshort)
0.00
0.05
0.10
0.15
0 1 2 3 4 5 6 7 8
PT (GeV/c)
PT
Pa
rtic
le R
ati
o
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.87 TeVNSD (|Y| < 2)
CMS DataPYTHIA Tune Z1 & Z1C
(+
)/(2Kshort)_
PT Particle Ratio: (Cas+CasBar)/(Lam+LamBar)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0 1 2 3 4 5 6 7 8
PT (GeV/c)
PT
Pa
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ati
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Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.87 TeVNSD (|Y| < 2)
CMS DataPYTHIA Tune Z1 & Z1C (
+
)/(+)_ _
CMS NSD data on the Cascade-+AntiCascade- to 2Kshort ratio versus pT at 7 TeV (|Y| < 2) compared with PYTHIA Tune Z1 & Z1C.
CMS NSD data on the Cascade-+AntiCascade- to Lambda+AntiLambda ratio versus pT at 7 TeV (|Y| < 2) compared with PYTHIA Tune Z1 & Z1C.
Tune Z1C is not too bad but a bit off on the pT dependence!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 38
Particle Ratios versus PTParticle Ratios versus PT
Proton Proton
“Minimum Bias” Collisions
PT Particle Ratio: Kaons/Pions
0.00
0.20
0.40
0.60
0 1 2 3 4
PT (GeV/c)
PT
Pa
rtic
le R
ati
o
(K++K-)/(++-)ALICE Data
PYTHIA Tune Z1 & Z1C
INEL (|Y| < 0.75) 900 GeV
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
Rapidity Distribution Ratio: Kaons/Pions
0.0
0.1
0.2
0.3
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
ticl
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ati
o
ALICE DataPYTHIA Tune Z1 & Z1C
INEL (all pT) 900 GeV
(K++K-)/(++-)
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
ALICE INEL data on the charged kaon to charged pion rapidity ratio at 900 GeV compared with PYTHIA Tune Z1.
ALICE INEL data on the charged kaons to charged pions ratio versus pT at 900 GeV (|Y| < 0.75) compared with PYTHIA Tune Z1 & Z1C.
Tune Z1C is not too bad but a way off on the pT dependence!
Tails of the pT distribution. Way off due to the wrong pT!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 39
Particle Ratios versus PTParticle Ratios versus PT
Proton Proton
“Minimum Bias” Collisions
PT Particle Ratio: (P+Pbar)/Pions
0.0
0.1
0.2
0.3
0.4
0 1 2 3 4
PT (GeV/c)
PT
Pa
rtic
le R
ati
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ALICE DataPYTHIA Tune Z1 & Z1C
INEL (|Y| < 0.75) 900 GeV
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
(p+p)/(++-)_
Rapidity Distribution Ratio: (P+Pbar)/Pions
0.00
0.03
0.06
0.09
0.12
-4 -3 -2 -1 0 1 2 3 4
Rapidity Y
dN
/dY
Par
ticl
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ati
o
INEL (all pT) 900 GeV
(p+p)/(++-)_ALICE Data
PYTHIA Tune Z1 & Z1C
Z1
Z1C
Tune Z1Cqq/q: 0.1 -> 0.12us/s: 0.4 -> 0.8
ALICE INEL data on the Proton+AntiProton to charged pions ratio versus pT at 900 GeV (|Y| < 0.75) compared with PYTHIA Tune Z1 & Z1C.
ALICE INEL data on the Proton+AntiProton to charged pion rapidity ratio at 900 GeV compared with PYTHIA Tune Z1 & Z1C.
Tune Z1C is not too bad but way off on the pT dependence!
Tails of the pT distribution. Way off due to the wrong pT!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 40
MB versus UEMB versus UE
Proton Proton
“Minimum Bias” Collisions
CMSTune Z1 NSD = ND + DD
CMS NSD data on the charged particle rapidity distribution at 7 TeV compared with PYTHIA Tune Z1. The plot shows the average number of charged particles per NSD collision per unit f, (1/NNSD) dN/ddf.
Charged Particle Density: dN/ddf
0.0
0.5
1.0
1.5
2.0
2.5
-4 -3 -2 -1 0 1 2 3 4
Pseudo-Rapidity
Ch
arg
ed
Par
ticl
e D
en
sit
y
pyZ1 ND = dashed
pyZ1 NSD = solid
CMS DataPYTHIA Tune Z1
NSD (all pT) 7 TeV
Transverse Charged Particle Density: dN/ddf
0.0
0.5
1.0
1.5
2.0
2.5
0 5 10 15 20 25
PT max (GeV/c)
Ch
arg
ed P
arti
cle
De
nsi
ty
7 TeV ND
Charged Particles (|| < 2, all pT)
RDF PreliminaryPYTHIA Tune Z1
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
Shows the density of charged particles in the “transverse” region as a function of PTmax for charged particles (All pT, || < 2) at 7 TeV from PYTHIA Tune Z1.
Tune Z1
Factor of 2!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 41
UE Particle TypeUE Particle Type
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
Transverse Charged Particle Density: dN/ddf
0.0
0.5
1.0
1.5
2.0
2.5
0 5 10 15 20 25
PT max (GeV/c)
Ch
arg
ed P
arti
cle
De
ns
ity
7 TeV ND
Charged Particles (|| < 2, all pT)
RDF PreliminaryPYTHIA Tune Z1
Shows the density of charged particles in the “transverse” region as a function of PTmax for charged particles (All pT, || < 2) at 7 TeV from PYTHIA Tune Z1.
Tune Z1
Transverse Particle Density: dN/ddf
0.001
0.010
0.100
1.000
10.000
0 5 10 15 20 25
PTmax (GeV/c)
Par
ticl
e D
ensi
ty
charged particles7 TeV ND
(|| < 2, all pT)
RDF PreliminaryPYTHIA Tune Z1
(+)_
(p+p)_
(+
)_
(K++K-)
(++-)
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
Shows the density of particles in the “transverse” region as a function of PTmax for charged particles (All pT, || < 2) at 7 TeV from PYTHIA Tune Z1.
Log Scale!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 42
Charged Particle Density: dN/ddf
0.00
0.05
0.10
0.15
-4 -3 -2 -1 0 1 2 3 4
Pseudo-Rapidity
Ch
arg
ed P
arti
cle
De
nsi
ty
7 TeV ND
Kshort (all pT)
RDF PreliminaryPYTHIA Tune Z1
Kshort
"Transverse" Particle Density: dN/ddf
0.00
0.05
0.10
0.15
0 5 10 15 20 25
PT max (GeV/c)
Par
tic
le D
en
sity
7 TeV ND
Kshort (|| < 2, all pT)
RDF PreliminaryPYTHIA Tune Z1
Kshort
MB versus UEMB versus UE
Proton Proton
“Minimum Bias” Collisions
Tune Z1
Shows the Kshort pseudo-rapidity distribution (all pT) at 7 TeV from PYTHIA Tune Z1. The plot shows the average number of particles per ND collision per unit f, (1/NND) dN/ddf.
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
Shows the density of Kshort particles in the “transverse” region as a function of PTmax for charged particles (All pT, || < 2) at 7 TeV from PYTHIA Tune Z1.
Tune Z1
Factor of ~2!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 43
"Transverse" Particle Density: dN/ddf
0.00
0.04
0.08
0.12
0 5 10 15 20 25
PT max (GeV/c)
Par
tic
le D
en
sity
(p+p)_
7 TeV ND (|| < 2,all pT)
RDF PreliminaryPYTHIA Tune Z1
Charged Particle Density: dN/ddf
0.00
0.04
0.08
0.12
-4 -3 -2 -1 0 1 2 3 4
Pseudo-Rapidity
Ch
arg
ed
Par
ticl
e D
en
sit
y
7 TeV ND (all pT)
RDF PreliminaryPYTHIA Tune Z1 (p+p)
_
MB versus UEMB versus UE
Proton Proton
“Minimum Bias” Collisions
Tune Z1
Shows the P+antiP pseudo-rapidity distribution (all pT) at 7 TeV from PYTHIA Tune Z1. The plot shows the average number of particles per ND collision per unit f, (1/NND) dN/ddf.
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
Shows the density of P+antiP particles in the “transverse” region as a function of PTmax for charged particles (All pT, || < 2) at 7 TeV from PYTHIA Tune Z1.
Tune Z1
Factor of ~2!
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 44
"Transverse" Particle Density: dN/ddf
0.00
0.01
0.02
0.03
0.04
0 5 10 15 20 25
PT max (GeV/c)
Par
tic
le D
en
sity
7 TeV ND (|| < 2,all pT)
RDF PreliminaryPYTHIA Tune Z1
(+)_
Charged Particle Density: dN/ddf
0.00
0.01
0.02
0.03
0.04
-4 -3 -2 -1 0 1 2 3 4
Pseudo-Rapidity
Ch
arg
ed P
arti
cle
De
nsi
ty
7 TeV ND (all pT)
RDF PreliminaryPYTHIA Tune Z1 (+)
_
MB versus UEMB versus UE
Proton Proton
“Minimum Bias” Collisions
Tune Z1
Shows the +anti pseudo-rapidity distribution (all pT) at 7 TeV from PYTHIA Tune Z1. The plot shows the average number of particles per ND collision per unit f, (1/NND) dN/ddf.
Proton Proton
PT(hard)
Outgoing Parton
Outgoing Parton
Underlying Event Underlying Event
Initial-State Radiation
Final-State Radiation
Shows the density of +anti particles in the “transverse” region as a function of PTmax for charged particles (All pT, || < 2) at 7 TeV from PYTHIA Tune Z1.
Tune Z1
Factor of ~2!
Coming soon! Measurements from CMS,ATLAS, and ALICE on the strange
particles and baryons in the “underlying event”.
Cracow School of Physics Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS Page 45
Fragmentation SummaryFragmentation SummaryNot too hard to get the overall yields of
baryons and strange particles roughly right at 900 GeV and 7 TeV. Tune Z1C does a fairly good job with the overall particle yields at 900 GeV and 7 TeV.
PT Distributions: PYTHIA does not describe correctly the pT distributions of heavy particles (MC softer than the data). None of the fragmentation parameters I have looked at changes the pT distributions. Hence, if one looks at particle ratios at large pT you can see big discrepancies between data and MC (out in the tails of the distributions)!
ATLAS Tuning Effort: Fragmentation flavor tuning at the one of the four stages.
Proton Proton
“Minimum Bias” Collisions
K+
u s
K-
u s
Kshort
d s s d + p
u u d
u d s
d s s
Other Fragmentation Tuning: There is additional tuning involving jet shapes, FSR, and ISR that I did not have time to include in this talk.
Warning! The Tune Z1C fragmentationparameters may cause problems
fitting the LEP data. If sowe must understand why!
We do not want one tune for e+e- and another one for
hadron-hadron collisions!