Transcript Energy and Centrality Dependence of Thermodynamics parameters

Multi-Strange Hadron Production in
High Energy Au+Au collision
Based on AMPT model
Ning Yu
Institute of Particle Physics
Central China Normal University
7/17/2015
16-19
0 October, CNPC 2013
Outline
 Introduction and Motivation
 AMPT model and Parton hadronization
 Multi-Strange hadrons Ω and ϕ production of mid-rapidity Au+Au
collision at √sNN=7.7~200 GeV
 pT spectra
 Mean pT and pT2 , <pT> <pT2>
 Baryon to Meson ratio
 Summary
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Introduction and Motivation
QCD Phase Diagram
 RHIC Beam Energy Scan Program
• Looking for onset of de-confinement,
sQGP (strongly coupled Quark Gluon
Plasma).
• Phase boundary and CP (critical point).
• Local strong parity violation.
 Some key observables for the formation
of Deconfinement in high-energy
nuclear collision.
• Strangeness enhancement
• Jet quenching RAA/RCP
arXiv:1007.2613
PRC78,034918
PRL99,112301
7/17/2015
• Partonic collectivity v2
• Baryon to meson ratio
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A Multi-Phase Transport Model(AMPT)
AMPT Default : The partonic part includes only minijets from the HIJING
model. Hadronization by Lund string fragmentation. Hadronic d.o.f. dominant.
AMPT StringMelting : All excited strings are converted to partons.
Hadronization by quark coalescence model. Partonic d.o.f. dominant.
Zi-Wei Lin, et. al.,Phys. Rev. C72,064901(2005)
 Scaling in v2: partonic d.o.f dominant;
 No scaling in v2 : hadronic d.o.f dominant
AMPT provide us a good reference to
study the Phase Boundary in QCD
Phase Diagram.
J.Phys. G 37,094029(2010)
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Multi-Strange Hadrons Ω and ϕ
Ω- /anti-Ω- ( sss / sss ) S=±3, m=1672.45 MeV
ϕ( ss ) S=0, m=1019.455 MeV
Constituent strange quarks produced in heavy-ion collision
Small hadronic interaction cross section (PRL81,5764; PRL53,1122)
They carry the information directly from the hadronization stage
Little decay feed-down correction
Multi-Strange hadrons are good tools to study the Deconfinement and
Phase Boundary in high energy nuclear collision.
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hall assume that all hadrons produced in heavy-ion collisions are formed by recombina-
collisions. In recent years the recombination model has been extensively studi
Hadronization
of quarks and/ or antiquarks, the original formulation of which is given in [10, 11] for pp
groups [12, 13, 14, 5] with great success in reproducing the pT spectra in the inte
 AMPT Default Lund string fragmentation,a string fragments into quarkantiquark pairs with a Gaussian distribution in transvers momentum.
ions. In recent years the recombination model has been extensively studied by many
region of Au+ Au collisions. In our 1D description of the recombination process t
ps [12, 13,
14, 5] with
success
in Coalescence,
reproducing the
pT spectra
in nearest
the intermediate pT
 AMPT
Stringgreat
melting
Quark
combine
the two
parton into a meson
and the three
nearest
quarks(antiquark)
nclusive distribution
of a produced
meson
with
momentum p into
is a
baryon(antibaryon)
n of Au+ Au
collisions. In our 1D description of the recombination process the invariant
 Recombination 0model
dN M mesondp
2
sive distribution
of a produced
wit1 hdpmomentum
isM (p1, p2, p),
p
=
Fq¯q (p1, p2p)R
dp
 For meson
p1 p2
dN M
dp1 dp2
=
F (p , p )R (p , p , p),
and for a produceddp
baryon p1 p2 q¯q 1 2 M 1 2
p0
(1)
 For baryon
or a produced baryon
0 dN B
p
dp
=
dp1 dp2 dp3
Fqq q (p1, p2, p3) RB (p1, p2, p3, p).
p1 p2 p3
PRC75,054904
0 dN B
dp1 dp2 dp3
Fqq q (p1, p2, p3) RB (p1, p2, p3, p).
(2)
dp
p
p
p
1
2
3 created by the collisions are imbedded in the
The properties of the medium
p
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=
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pT spectra
AMPT SM
6mbHadronic
Partonic
Default
3mb
1/(2p pTT)d22N/(dpTTdy) (c22/GeV22)
10
10
7.7 GeV
19.6 GeV
AMPT
AMPT
Default
SM6mb
3mb
SM
10
10-4-4
0-10%
0-10%
10-20%/10
10-20%/10
-9
10
10-9
2
20-40%/10
20-40%/102
3
40-60%/10
40-60%/103
4
60-80%/10
60-80%/104
10 00
11 22 33 44
39 GeV
39 GeV
55
66
77
00
22
66
88
200
GeV44 STAR
DATA
f meson
|y| £ 0.5
10-4-4
0-10%
0-10%
10-20%/10
10-20%/10
2
20-40%/10
20-40%/102
3
40-60%/10
40-60%/103
4
60-80%/10
60-80%/104
10-9-9
0
1 2 3 4 5 6 7 0
2
4
6
8
7.7
19.6
7.7 GeV
GeV Momentum p (GeV/c)
19.6 GeV
GeV AMPT
Transverse
AMPT
Default
TT
1/(2p pTT)d22N/(dpTTdy) (c22/GeV22)
SM 6mb
3mb
0-10%
0-10%
10-20%/10
10-20%/10
-5
-5
10
10
2
20-40%/10
20-40%/102
3
40-60%/10
40-60%/103
4
60-80%/10
60-80%/104
-10
10
10-10
00
11 22 GeV
39 33 44
55
66
77
00
10-5-5
22 GeV
44
66
88
200
STAR DATA
W baryon
|y| £ 0.5
0-10%
0-10%
10-20%/10
10-20%/10
2
20-40%/10
20-40%/102
3
40-60%/10
40-60%/103
4
60-80%/10
60-80%/104
-10
-10
10
0
1 2 3 4 5 6 7 0
2
Transverse Momentum pT (GeV/c)
T
4
6
 The pT spectra from SM are softer than
Default, both Default (at high pT)and SM model
are softer than measured in experiment.
 Default model gives better reasonable
description pT distribution of Ω and ϕ than
those from SM model.
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Star Data: QM12 &PRL 99,112301(2007)
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<pT> and <p2T> of ϕ meson
SM 6mb Partonic
Default Hadronic
<pt>(GeV/c)
<pt>(GeV/c)
1.2
7.7 GeV AMPT SM spp=6mb
19.6 GeV 1.2 f meson
39 GeV
200 GeV
AMPT Default
f meson
1
0.8
show obvious energy and
centrality dependence.
 In SM model, energy
dependece of <pT> is
0.6
100
200
AMPT Default Npart
f meson
300
0
100
200
Npart
7.7 GeV AMPT SM spp=6mb
19.6 GeV 1.5 f meson
39 GeV
200 GeV
<p2t>(GeV2/c2)
<p2t>(GeV2/c2)
1.5
1
 In Default model, <pT>
0.8
0.6
0
7.7 GeV
19.6 GeV
39 GeV
200 GeV
1
300
7.7 GeV
19.6 GeV
39 GeV
200 GeV
1
restore when √sNN≥19.6
GeV. No obvious centrality
dependence.
 In SM model, partonic
interaction is not strong
enough to produce the
0.5
0
0.5
100
200
Npart
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300
0
100
200
Npart
7
300
collectivity in Default model.
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Ω Baryon to Φ Meson ratio
0.2
2
4
Transverse Momentum pT (GeV/c)
0.4
(W +W )(pT)/(f(pT))
0.3
+
0.2
0.1
60
AMPT SM spp=6mb 0-10%
Hwa&Yang
Star :200 GeV (0-12%)
7.7 GeV
19.6 GeV
39 GeV
200 GeV
-
0.1
0
0.3
AMPT SM spp=3mb 0-10%
Hwa&Yang
Star :200 GeV (0-12%)
7.7 GeV
19.6 GeV
39 GeV
200 GeV
-
-
+
0.2
0.4
+
0.3
AMPT Default 0-10%
Hwa&Yang
Star :200 GeV (0-12%)
7.7 GeV
19.6 GeV
39 GeV
200 GeV
(W +W )(pT)/(f(pT))
(W +W )(pT)/(f(pT))
0.4
2
4
Transverse Momentum pT (GeV/c)
0.1
60
2
4
Transverse Momentum pT (GeV/c)
6
 Recombination :at √sNN=200 GeV, the ratios rise linearly to pT≈4 GeV/c and develops a
maximum at pT ≈ 5 GeV/c. Describes the trend of STAR data up to 4 GeV/c but fails at
higher pT. (PRC75,054904)
 AMPT Default : energy dependence, which means Lund fragmentation model is energy
dependent. The ratios do not show obviously enhancement and suppression.
 AMPT SM : better descript both the magnitude and the enhancement and suppression of
the ratios. Difference of the ratios between 7.7 GeV and those above 19.6 GeV.
Quark Coalescence model is not suitable at energy below 7.7~19.6 GeV?
Partonic dynamics is different between 7.7 and 19.6 GeV?
Deconfinement matter formation above 19.6 GeV?
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Ω Baryon to Φ Meson ratio
AMPT Default
0.3
7.7 GeV
Hwa&Yang (total)
0-10%
20-40%
40-60%
 STAR Data at 200 GeV: no strong centrality
dependence at the low pT < 3GeV/c region.
0.1
0
39 GeV
0.3
200 GeV
STAR DATA
0-12%
20-40%
40-60%
-
+
(W +W )(pT)/(f(pT))
0.2
19.6 GeV
0.2
 AMPT Default : centrality dependence
0.1
0
0
0.3
AMPTMomentum
SM spppT=6mb
Transverse
(GeV/c)
4
0
2
7.7 GeV
Hwa&Yang (total)
0-10%
20-40%
40-60%
19.6 GeV
39 GeV
200 GeV
STAR DATA
0-12%
20-40%
40-60%
4
6

0.1
0
0.3
-
+
(W +W )(pT)/(f(pT))
0.2
2
0.2
 AMPT SM : centrality dependence at low
energy and become weaker with increasing
energy
Although SM mode provides a stronger pT
dependence in the ratio compared to that of
the Default mode, all model results show a
lower ratios comparing to experimental data.
0.1
0
0
2
4
0
2
4
6
Transverse Momentum pT (GeV/c)
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10-5 0
1
psT=pT/nq (GeV/c)
2
T
10-4
10-5 0
1
psT=pT/nq (GeV/c)
2
2f(2ps )
T
+
-
10
AMPT SM spp=3mb 0-10%
7.7 GeV
10-2
19.6 GeV
39 GeV
200 GeV -3
(W +W )(3ps )
T
10-4
2f(2ps )
T
+
10-3
-
T
2f(2ps )
+
-
AMPT Default 0-10%
7.7 GeV
10-2
19.6 GeV
39 GeV
200 GeV -3
(W +W )(3ps )
10-2
T
(W +W )(3ps )
Ratios NCQ Scaling
AMPT SM spp=6mb 0-10%
7.7 GeV
19.6 GeV
39 GeV
200 GeV
10
10-4
10-5 0
1
psT=pT/nq (GeV/c)
2
 Lund Fragmentation (Default) : the ratio increases with increasing collision energy.
 Coalescence (SM) : Ω and ϕ formed at chemical freeze out from coalescence of 3 s
quarks and s-sbar pairs. Assuming coalescence of s quarks of approximately equal pT and
the same shape of pT distributions for s and sbar quarks. The pT distribution of s quark at
freeze-out is proportional to Ω (3pT)/ϕ(2pT).
 The NCQ scaled ratios is sensitive to the partonic dynamics at hadronaziation.
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Ratios NCQ Scaling
AMPT SM spp=6mb
AMPT Default
39 GeV
200 GeV
-2
10
+
-
10-4
-2
10
-3
10-3
7.7 GeV
0-10%
20-40%
40-60%
19.6 GeV
39 GeV
200 GeV
T
2f(2ps )
T
(W +W )(3ps )
10-3
19.6 GeV
T
2f(2ps )
-
+
T
(W +W )(3ps )
10-2
7.7 GeV
0-10%
20-40%
40-60%
10-4
-2
10
-3
10
10
10-4
0
0.5
1
1.5
0.5
ps =p /n q (GeV/c)
T
1
1.5
10-4
2 0
T
0.5
1
1.5
0.5
ps =p /n q (GeV/c)
T
1
1.5
2
T
 AMPT Default : centrality dependent
 AMPT SM : centrality dependent at low energy and become weaker with
increasing energy.

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At high energy collisions, √s > 19.6 GeV, for example, Partonic Dynamics
becomes dominant.
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Summary
 Ω and ϕ are special hadron in high-energy collision,
their production are good tools to study the
Deconfinement and Phase Boundary.
 The pT spectra from AMPT are softer than measured
in experiment.
 Quark Coalescence is not suitable at energy below
7.7~19.6 GeV in the most central collision and at
peripheral collision at certain energy. No
Deconfinement and Hadronic interaction are more
important in these cases.
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Acknowledgments
Yang Chunbing, Liu Feng, Nu Xu.
Thank You
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Backup
• Star results
Short paper plots
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ShortBackup
paper plots
Fig. 5
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