MB&UE Working Group Meeting
February 7 & 8, 2011
Kaons, Protons & Antiprotons
CMS
Rick Field
University of Florida
Outline of Talk
ATLAS
 PYTHIA 6.4 Tune Z1: Charged kaon, proton, and
antiproton production in min-bias collisions.
 PYTHIA 6.4 Tune Z1: Charged kaon, proton, and
antiproton production in the underlying event.
Outgoing Parton
“Minimum Bias” Collisions
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
Proton
Proton
Underlying Event
Final-State
Radiation
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 1
Strange Particle Production
Factor of 2!
ALICE preliminary
stat. error only
Jan Fiete Grosse-Oetringhaus
LPCC MB&UE Meeting
September 2010
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.
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 2
Charged Particle dN/dh 7 TeV
Charged Particle Density: dN/dh
Charged Particle
Particle Density:
Density: dN/dh
dN/dh
Charged
8
810.000
PYTHIA Tune Z1 7 TeV
All pT
ChargedParticle
ParticleDensity
Ratio
Charged
Charged Particle Density
PYTHIA Tune Z1 ND 7 TeV
pT > 0.5 GeV/c
6
pT > 1.0 GeV/c
4
2
0
INEL
6 1.000
All All
pT pT
pT > 0.5 GeV/c
pT > 1.0 GeV/c
pT > 2.0 GeV/c
4 0.100
ND
pT >3.0 GeV/c
DD
2 0.010
SD
PYTHIA Tune Z1 ND 7 TeV
0 0.001
-10
-8
-6
-4
-2
0
2
4
6
8
10
-10
-10-8
-8 -6
PseudoRapidity h
-6 -4
-4 -2 -2
0 0
2 2
44
66
88
10
10
PseudoRapidity
PseudoRapidity
h h
 Charged particle (direct, including leptons) pseudorapidity distribution, dN/dh (ND), at 7 TeV for
all pT, pT > 0.5 GeV/c, pT > 1.0 GeV/c, pT > 2.0 GeV/c, and pT > 3.0 GeV/c from Tune Z1.
 Charged particle (direct, including leptons) pseudorapidity distribution, dN/dh, at 7 TeV for all pT
from Tune Z1. Shows the individual contributions from ND, SD, DD, and INEL = ND + SD + DD.
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 3
Charged Particle dN/dh 7 TeV
Charged Particle Ratio: Flavor/All Charged
1.2
sum
1.2
All pT
1.0
0.8
p+ + p-
0.6
0.4
K + + K-
proton
sum
PYTHIA Tune Z1 7 TeV INEL
Charged Particle Ratio
Charged Particle Ratio
PYTHIA Tune Z1 7 TeV ND
Charged Particle Ratio: Flavor/All Charged
Antiproton
0.2
0.0
All pT
1.0
0.8
p+ + p-
0.6
proton
0.4
K + + K-
Antiproton
0.2
0.0
-10
-8
-6
-4
-2
0
2
4
6
8
10
-10
-8
PseudoRapidity h
-6
-4
-2
0
2
4
6
8
10
PseudoRapidity h
 Charged particle ratios versus h at 7 TeV (ND all pT). Shows (p+ +p-)/(all charged), (K+ + K-)/(all
charged), proton/(all charged), antiproton/(all charged), and sum/(all charged), where sum = p+ +
p- + K+ + K- + p + pbar.
 Charged particle ratios versus h at 7 TeV (INEL = ND + SD +DD all pT). Shows (p+ +p-)/(all
charged), (K+ + K-)/(all charged), proton/(all charged), antiproton/(all charged), and sum/(all
charged), where sum = p+ + p- + K+ + K- + p + pbar.
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 4
Charged Particle dN/dh 7 TeV
Charged Particle
Particle Ratio:
Ratio: Flavor/All
Flavor/All Charged
Charged
Charged
ChargedParticle
ParticleRatio:
Ratio:Flavor/All
Flavor/AllCharged
Charged
Charged
1.2
1.2
1.2
sum
sum
sum
pTGeV/c
pT All
1.0
pT
>> 3.0
GeV/c
1.0
1.0
1.0
Charged
ChargedParticle
ParticleRatio
Ratio
Charged
Charged Particle
Particle Ratio
Ratio
PYTHIA
PYTHIA Tune
Tune Z1
Z1 77 TeV
TeV ND
ND
1.2
1.2
p+ + p-
0.8
0.8
0.8
p+ + p-
0.6
0.6
0.6
p +p
+
0.4
0.4
0.4
++ + K
Antiproton
KK
+ KK- + + K-Antiproton
Antiproton
proton
proton
proton
0.2
0.2
0.2
0.0
0.0
0.0
-10
-10
-10
1.0
1.0
PYTHIA Tune Z1 7 TeV ND
PYTHIA Tune Z1 7 TeV ND
sum
sum
pT0.5
> 2.0
GeV/c
pT >
GeV/c
p+ + p-
0.8
0.8
0.6
0.6
+
proton p + p
Antiproton
Antiproton
K+ + K K+ + K -
0.4
0.4
proton
0.2
0.2
0.0
0.0
-8
-8
-8
-6
-6
-6
-4
-4
-4
-2
-2
-2
000
222
444
666
888
10
10
10
-10
-10
-8
-8
-6
-6
-4
-4
-2
-2
00
22
44
66
88
10
10
PseudoRapidityhh
PseudoRapidity
PseudoRapidityhhh
PseudoRapidity
PseudoRapidity
 Charged particle ratios versus h at 7 TeV (ND all pT). Shows (p+ +p-)/(all charged), (K+ + K-)/(all
charged), proton/(all charged), antiproton/(all charged), and sum/(all charged), where sum = p+ +
p- + K+ + K- + p + pbar.
 Charged particle ratios versus h at 7 TeV (ND pT > 0.5 GeV/c). Shows (p+ +p-)/(all charged), (K+ +
K-)/(all charged), proton/(all charged), antiproton/(all charged), and sum/(all charged), where sum
= p+ + p- + K+ + K- + p + pbar.
 Charged particle ratios versus h at 7 TeV (ND pT > 1.0 GeV/c). Shows (p+ +p-)/(all charged), (K+ +
K-)/(all charged), proton/(all charged), antiproton/(all charged), and sum/(all charged), where sum
= p+ + p- + K+ + K- + p + pbar.
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 5
Charged Particle Ratios
Charged Particle
Particle Ratio:
Ratio: Flavor/All
Flavor/All Charged
Charged
Charged
sum
sum
PYTHIA Tune
Tune Z1
Z1 77 TeV
TeV INEL
ND0.6
PYTHIA
1.0
1.0
0.6
0.6
+
-
K +K
K+ + K-
0.4
0.4
0.2
0.2
0.0
0.0
00
11
Strange Particle Ratio
PYTHIA Tune Z1 7 TeV
0.8
0.8
+
p0.5
+ pp+ + p-
0.4
pp++pbar
pbar
0.3
sum
PYTHIA Tune Z1 7 TeV ND
2
|h||h|< <0.8
Charged Particle Ratio
1.2
1.2
Charged
Charged Particle
Particle Ratio
Ratio
Charged Particle Ratio: Flavor/All Charged
Strange Particle Ratio:1.2
(K+ + K-)/(p+ + p-)
1.0
|h| < 0.8
|h| < 0.8
0.8
p+ + p-
0.6
K+ + K-
0.4
p + pbar
0.2
0.2
0.0
220.1
PT (GeV/c)
(GeV/c)
PT
33
44
55
0
1
2
3
4
5
ND = open squares INEL = black dotsPT (GeV/c)
0.0
+ 2.5+
1.0
1.5
2.0
3.0
 Charged particle ratios0.0versus p0.5
T at 7 TeV (ND |h| < 2). Shows (p +p )/(all charged), (K + K )/(all
PTcharged),
(GeV/c)
charged), (p + pbar)/(all charged), and sum/(all
where sum = p+ + p- + K+ + K- + p +
pbar.
 Charged particle ratios versus pT at 7 TeV (ND |h| < 0.8). Shows (p+ +p-)/(all charged), (K+ + K)/(all charged), (p + pbar)/(all charged), and sum/(all charged), where sum = p+ + p- + K+ + K- + p
+ pbar.
 Charged particle ratios versus pT at 7 TeV (INEL |h| < 0.8). Shows (p+ +p-)/(all charged), (K+ + K)/(all charged), (p + pbar)/(all charged), and sum/(all charged), where sum = p+ + p- + K+ + K- + p
+ pbar.
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 6
Charged Particle Ratios
Charged Particle Ratio: Flavor/All Charged
Charged
Particle
Charged
Particle
Ratio: Density:
Flavor/AlldN/dh
Charged
+
Strange Particle Ratio: (K
+ K-)/(p+ + p-)
1.2
8
1.2
sum
7 TeVAll pT
1.0
6
0.8
All pT
Strange Particle Ratio
PYTHIA Tune Z1 ND
0.5
p+ + 0.4
p-
4
0.6
0.4
2
0.2
proton
K + + K-
0.3
Antiproton
900 GeV
0
0.0
-10
-8
-6
-4
-4
sum
PYTHIA Tune Z1 900 GeV ND
Charged Particle Ratio
Charged Particle Ratio
Charged Particle Density
PYTHIA
TeV ND0.6
PYTHIATune
Tune Z1
Z1 7ND
1.0
All pT
|h| < 0.8
0.8
p+ + p-
0.6
0.4
K + + K-
proton
Antiproton
0.2
0.2
0.0
-20.1
-2
00
22
PseudoRapidityhh
PseudoRapidity
44
66
88
1010
-10
-8
-6
-4
-2
0
2
4
6
8
10
900 GeV = open squares
PseudoRapidity h
7 TeV = black dots
0.0
0.0
0.5
1.0
1.5
2.0 distribution,
2.5
3.0
 Charged particle (direct,
including
leptons)
pseudorapidity
dN/dh
(ND all pT), at 7
PT (GeV/c)
TeV and 900 GeV from Tune Z1.
 Charged particle ratios versus h at 900 GeV (ND all pT). Shows (p+ +p-)/(all charged), (K+ + K)/(all charged), proton/(all charged), antiproton/(all charged), and sum/(all charged), where sum =
p+ + p- + K+ + K- + p + pbar.
 Charged particle ratios versus h at 7 TeV (ND all pT). Shows (p+ +p-)/(all charged), (K+ + K-)/(all
charged), proton/(all charged), antiproton/(all charged), and sum/(all charged), where sum = p+ +
p- + K+ + K- + p + pbar.
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 7
Strange Particle Production
Strange Particle Ratio: (K+ + K-)/(p+ + p-)
0.6
PYTHIA Tune Z1 ND 900 GeV
|h| < 0.8
Factor of 2!
Strange Particle Ratio
0.5
Plateau!
0.4
0.3
0.2
0.1
0.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
PT (GeV/c)
 A lot more strange mesons at large pT than predicted by the Monte-Carlo
Models and a different shape of the curve!
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 8
PYTHIA Fragmentation
Parameters
 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.
 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.
 PARJ(3) : (D = 0.4) is (P(us)/P(ud))/(P(s)/P(d)), the extra suppression of strange diquark
production compared with the normal suppression of strange quarks.
 PARJ(4) : (D = 0.05) is (1/3)P(ud1)/P(ud0), the suppression of spin 1 diquarks compared with
spin 0 ones (excluding the factor 3 coming from spin counting).
Look at the affect of
changing PARJ(2)
from 0.3 to 0.5!
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 9
Charged Particle Ratios
Charged
Particle
Ratio:Density:
Flavor/All
Charged
Charged
Particle
dN/dh
Charged
Particle
Ratio:
Flavor/All
Charged
1.2
8
1.2
All pT
0.0
0
0.0
0
-10
-10
0.5
p+ + p-
p+ + p0.4
0.6
4
0.6
0.4
0.4
2
0.2
0.2
Strange Particle Ratio
PYTHIA Tune Z1 ND 900 GeV
s/u = 0.5
+
-
K +proton
K
-8-8
-6-61
-4
-4
0.3
sum
sum
PYTHIA
= 0.5
PYTHIA Tune
Tune Z1
Z1 77 TeV
TeV ND
ND s/u
(s/u=0.5)
Charged
Charged Particle
Particle Ratio
Ratio
1.0
1.0
6
0.8
0.8
1.2
sum
sum s/u = 0.3
All|h|
pT< 0.8
(default)
PYTHIA
Tune
Z1
ND0.6
PYTHIA
Tune
77 TeV
ND
PYTHIA
Tune
Z1Z1
ND
7TeV
TeV
Charged
Particle
Ratio
Charged
ChargedParticle
ParticleDensity
Ratio
Charged Particle
Particle Ratio:
Ratio: Flavor/All
Flavor/All Charged
Charged
Charged
Strange Particle Ratio: 1.2
(K+ + K-)/(p+ + p-)
s/u = 0.5
K+ + Kp- + pbar
Antiproton
0.2
1.0
1.0
All pT
|h| < 0.8
|h| < 0.8
0.8
0.8
p+ + p-
0.6
0.6
p+ + pK+ proton
+ K-
0.4
0.4
Antiproton
K+ + K- p + pbar
0.2
0.2
0.0
0.0
s/u
= 0.3 (default)
-2
-220.1 00
223
4
64
88
105
10
0
-10
-8
PT (GeV/c) hh
PseudoRapidity
PseudoRapidity
-61
-4
-22
0
23
4
64
8
105
PT (GeV/c) h
PseudoRapidity
0.0
0.0 including
0.5 leptons)
1.0 pseudorapidity
1.5
2.0distribution,
2.5
3.0
 Charged particle (direct,
dN/dh
(ND all pT), at 7
PT (GeV/c)
TeV for PARJ(2) = s/u = 0.3 (default) and PARJ(2)
= s/u = 0.5 from Tune Z1.
 Charged particle ratios versus h at 7 TeV (ND all pT) with PARJ(2) = s/u = 0.3 (default) and
PARJ(2) = s/u = 0.5 from Tune Z1. Shows (p+ +p-)/(all charged), (K+ + K-)/(all charged), proton/(all
charged), antiproton/(all charged), and sum/(all charged), where sum = p+ + p- + K+ + K- + p +
pbar.
 Charged particle ratios versus pT at 7 TeV (ND |h| < 0.8) with PARJ(2) = s/u = 0.3 (default) and
PARJ(2) = s/u = 0.5 from Tune Z1. Shows (p+ +p-)/(all charged), (K+ + K-)/(all charged), (p +
pbar)/(all charged), and sum/(all charged), where sum = p+ + p- + K+ + K- + p + pbar.
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 10
Strange Particle Production
Not good!
Strange Particle Ratio: (K+ + K-)/(p+ + p-)
0.6
Plateau!
PYTHIA Tune Z1 ND 900 GeV
|h| < 0.8
Strange Particle Ratio
0.5
0.4
0.3
0.2
s/u = 0.5
0.1
0.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
PT (GeV/c)
 A lot more strange mesons at large pT than predicted by the Monte-Carlo Models and a
different shape of the curve!
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 11
Protons & Antiprotons
Proton+AntiP Ratio: (p+pbar)/(p+ + p-)
ALICE preliminary
stat. error only
0.35
PYTHIA Tune Z1 ND 900 GeV
|h| < 0.8
Jan Fiete Grosse-Oetringhaus
LPCC MB&UE Meeting
September 2010
Baryon Particle Ratio
0.30
0.25
0.20
0.15
Phojet
Pythia ATLAS-CSC
Pythia D6T
Pythia Perugia-0
0.10
0.05
0.00
0.0
0.5
1.0
1.5
2.0
2.5
3.0
PT (GeV/c)
 Tune Z1 (ND) does not get this right either and this curve does not depend on PARJ(2)!
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 12
The Underlying Event
"Transverse" Charged Particle Density: dN/dhdf
RDF Preliminary
"Transverse" Charged Particle Density: dN/dhdf
"Transverse" Charged Density
"Transverse" Charged Density
1.2
7 TeV
ALICE corrected data
Tune Z1 generator level
0.8
900 GeV
0.4
ALICE
Tune Z1
Charged Particles (|h|<0.8, PT>0.5 GeV/c)
1.2
RDF PreliminaryPTmax Direction
0.8
7 TeV
f
ATLAS corrected data
Tune Z1 generator level
“Toward”
Leading Charged
Particle, PTmax.
900 GeV
“Transverse”
0.4
“Transverse”
“Away”
Tune Z1
ATLAS
Charged Particles (|h|<2.5, PT>0.5 GeV/c)
0.0
0.0
0
5
10
15
20
25
0
2
6
8
10
12
14
16
18
 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.
 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.
ALICE UE Data: Talk by S. Vallero
ATLAS Note: ATLAS-CONF-2010-029
MPI@LHC 2010 Glasgow, Scotland
May 29, 2010
November 30, 2010
LPCC MB&UE Working Group
CERN February 7, 2011
20
PTmax (GeV/c)
PTmax (GeV/c)
I read the points off
with a ruler!
4
Rick Field – Florida/CDF/CMS
Page 13
“Transverse” Particle Ratios
Leading Particle Ratio: Flavor/All Charged
1.2
1.2
sum
PYTHIA Tune Z1 7 TeV ND
|h| < 2
PYTHIA Tune Z1 7 TeV ND
1.0
Charged Particle Ratio
Charged Particle Ratio
"Transverse" Ratio: Flavor/All Charged
PTmax Direction
p+ + p-
0.8
0.6
+
K +K
0.4
-
p + pbar
0.2
1.0
f
sum
|h| < 2 pT > 0.5 GeV/c
“Toward”
0.8
0.6
“Transverse”
0.4
p+ + p“Transverse”
p + pbar
K + + K-
“Away”
0.2
0.0
0.0
0
2
4
6
8
10
0
2
4
6
8
10
PTmax (GeV/c)
PTmax (GeV/c)
 Leading charged particle ratios versus pT at 7 TeV (|h| < 2.0). Shows (p+ +p-)/(all charged), (K+ +
K-)/(all charged), (p + pbar)/(all charged), and sum/(all charged), where sum = p+ + p- + K+ + K- +
p + pbar.
 Charged particle ratios in the “transverse” region (pT > 0.5 GeV/c, |h| < 2.0) versus the leading
charged particle, PTmax, at 7 TeV. Shows (p+ +p-)/(all charged), (K+ + K-)/(all charged), (p +
pbar)/(all charged), and sum/(all charged), where sum = p+ + p- + K+ + K- + p + pbar.
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 14
Summary
 So far no luck at fitting the min-bias charged kaon to charged pion ratio.
Increasing s/u produces more strange particles, but the shape of the curve
versus pT is different! But I am just getting started at this!
 Also not getting the protons + antiprotons right. Changing PARJ(2) does
nothing here! Must check out some of the other parameters
 The Monte-Carlo models are constrained by LEP data. Must make sure
that I do not destroy the agreement with the LEP data!
 We need a better understanding and modeling of diffraction!
protons
Diffraction
antiprotonss
LPCC MB&UE Working Group
CERN February 7, 2011
Rick Field – Florida/CDF/CMS
Page 15