Transcript Slide Title - Wayne State University

Di-hadron correlation and Mach-like cone
structures in parton/hadron transport model
Y. G. Ma
Shanghai INstitute of Applied Physics (SINAP)
Chinese Academy of Sciences

Background introduction

Model introduction

Analysis method
Results and discussions
Conclusion


Di-hadron correlations
pT(assoc) > 2 GeV/c
Associated
particles
On away side:
Hard associated
particles →
suppression
pT(assoc) > 0.15 GeV/c
At Middle pT →
???
Soft associated
particles →
enhancement
Soft Associated particles
on Away side
(thermalization)
What happens to a hard probe that
traverses a colored medium?
SOFTENED
soften + broaden =?= thermalization
near side
away side
thermalization???
BROADENED
BROADENED
SOFTENED
Mach-like cone Structure
nucl-ex 0510055
nucl-ex 0507004
PHENIX Preliminary
2.5<pTtrigger < 4.0 GeV/c x
1.0<pTassoc<2.5 GeV/c
Split parameter D
Possible interpretations of mach-like cone structure
Wake Effect or “sonic boom”
Θemission= arccos (cs/c)
hep-ph/0411315 CasalderreySolana,Shuryak,Teaney
nucl-th/0406018 Stöecker
Hep-ph/0503158 Muller,Ruppert
nucl-th/0503028 A. K. Chaudhuri
Cherenkov gluon radiation
Θemission= arccos (1/n(p))
nucl-th/0507063 Koch, Majumder, X.-N. Wang
Correlation of Jet with flowing medium
hep-ph/0411341 Armesto,Salgado,Wiedemann
AMPT model
A Multi-Phase Transport model, Ko & Lin et al.
(1) Default AMPT
(2) Melt AMPT
v2 vs pT
2.Consistent with experimental result (pT>1.5GeV/c).
J. H. Chen, YGM et al., Nucl-th/0504055
X.Cai, M.Oldenburg QM05(STAR)
D.Pal QM05(PHENIX)
1.Hydrodynamic behavior in AMPT (pT<1.5GeV/c), stronger v2
vs. data, 10mb.



(1) Get raw 
correlation signal
in same event
(2)Get respective
background by
mixing events in
same centrality
(3)Get 
correlation by
removing
background with
ZYAM method
1/NtrigdNch/d
Mixing-event Technique
530
520
510
500
490
480
470
4608
trig
PT 3-6GeV/c ,PT
asso
0.15-3GeV/c
same event
mix event
20-40%
6
20-40%
4
2
0
-1
0
1
2

3
4
5
Background
Subtracted signal
 correlations from AMPT
(3<pTtrigger<6GeV/c ,0.15<pTassoc<3GeV/c)
1/NtrigdN/d
(1) ▲melt after
Au+Au 200GeV (0-10%)
hadron cascade
8
AMPT 0-10%,(3-6) x (0.15-3)GeV/c
(2) ● melt
7
melt after hadron cascade
before hadron
melt before hadron cascade
default after hadron cascade
6
cascade
default before hadron cascade
Star Data 0-5% (4-6) x (0.15-4)GeV/c factor=1.58
(3)◆ default
5
after hadron
4
cascade
(4)★ default
3
before hadron
2
cascade
1
(5) ■ Star Data
0-5% (40
6)*(0.15-4)GeV/c
-1
0
1
2
3
4
5
factor=1.58
(rad)
Jet remnants character from AMPT
Au+Au 200GeV
2
20
10
16
trig
PT
14
(a)
near
away
4-6GeV/c ( STAR data X factor=1.58)
near
trig
(b)
PT
-1
associated Nhadron
18
3-6GeV/c (AMPT)
away
12
10
8
6
4
dNhadron/dP (GeV/c)
trig
PT
(STAR data X factor=1.58)
0-5% away
0-5% near X 0.1
1
10
0
10
-1
10
trig
PT
-2
10
3-6GeV/c (AMPT)
0-5% away
0-5% near X 0.1
2
-3
10
0
2
4
6
8
10
12
0
1
trig
PT
3-6 (AMPT)
near
trig
PT
away
3
4
(d)
4-6 (STAR data)
near
2
PT (GeV/c)
away
10
1.0
<PT> (GeV/c)
PT magnitude sum (GeV/c)
impact parameter b (fm)
12
4-6GeV/c
0.9
8
6
trig
PT
trig
PT
3-6GeV/c(AMPT)
away
4-6GeV/c(STAR data)
away
0.8
4
0.7
(c)
2
2
4
6
8
10
12
impact parameter b (fm)
2
4
6
8
10
impact parameter b (fm)
12
1.2
1.0
0.9
0.8
0.7
0.6
0.5
trig
AMPT PT 2.5-4(GeV/c),PT
1-3.(GeV/c)
melting after hadron cascade
defaulting after hadron cascade
trig
associated
experiment PT 2.5-4(GeV/c),PT
2-3(GeV/c)
0.4
0.3
0.2
associated
2
4
6
8
10
impact parameter b (fm)
12
1/NtrigdN/d
0-10%
0.3
0.2
0.1
-0.1
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
-0.1
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
-0.1
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
-0.1
0
1/NtrigdN/d
1.1
0.4
0-10% (2.5-4)X(1-2.5)GeV/c
melt after hadron cascade factor=1/12
melt before hadron cascade factor=1/12
default after hadron cascade factor=1/5
default before hadron cascade factor=1/5
Phenix Data 0-5% factor=1.58
D
0.0
1/NtrigdN/d
spliting parameter D (rad)
 correlations in Au+Au 200GeV
(2.5<pTtrigger<4GeV/c ,1<pTassoc<2.5GeV/c)
0.5
1/NtrigdN/d
Mach-like cone
Structure in
AMPT model
10-20% (2.5-4)X(1-2.5)GeV/c
melt after hadron cascade factor=1/5
melt before hadron cascade factor=1/5
default after hadron cascade factor=1/2
Phenix Data 10-20% faxtor=1.58
10-20%
20-40% (2.5-4)X(1-2.5)GeV/c
melt after hadron cascade factor=1/5
melt before hadron cascade factor=1/5
default after hadron cascade factor=1/2
Phenix Data 20-40% factor=1.58
20-40%
40-90% (2.5-4)X(1-2.5)GeV/c
melt after hadron cascade factor=1/4
melt before hadron cascade factor=1/4
default after hadron cascade factor=1/2
Phenix Data 60-90% factor=1.58
40-90%
1
(rad)
2
3
Special trigger/associated particle
3
6.0


kaon
2
1
(2.5-4)X(1-3.0) GeV/c
near side
away side
Au+Au 200GeV (0-10%)
Melt AMPT
after hadron cascade
special trigger particle
6.5
associated Nh
1/NtrigdN/d
7.0
(2.5-4.0)X(1.0-3.0) GeV/c Melt AMPT(0-10%)
after hadron cascade
special trigger particle
D-meson
proton
4
5.5
5.0
4.5
4.0
3.5
3.0
2.5
0
2.0
1.5
0
1
2
3

0
K
400
p
800


0.6
0.4
0.2
1.2
1.0
0.8
0.6
Au+Au 200GeV (0-10%)
Melt AMPT
after hadron cascade
special associated particle
0.4
0.0
1
2
(Rad)
2000
bayon/meson
near: 0.241
away: 0.283
0.2
0.0
0
1600
(2.5-4)X(1-3.0) GeV/c
near side
away side
1.4
associated Nh
1/NtrigdNhadron/d
0.8
1200
1.6
(2.5-4.0)X(1.0-3.0) GeV/c Melt AMPT 0-10%
after hadron cascade
special associated particle
kaon
proton
1.0
D
m0 (MeV)
(Rad)
1.2

3

0
K
200
400
p
600
m0 (MeV)
800
1000

1200
Three-particle correlations in AMPT
mix-event technique
background subtracted
3-particle correlation signal
Parton cascade effect on 2- and
3- particle correlation
(1)hadron cascade
mechanism also can
produce 2- and 3-particle
correlation, but it can
not give big enough
splitting parameters.
(2) the parton cascade
mechanism is essential
for describing the
amplitude of
experimental mach-like
structure
Conclusion
1)
Di-hadron correlations can be produced by a a
multi-phase transport model (AMPT).
2)
Mach-like structure is born in the partonic
process and further developed in hadronic
rescattering process.
3)
hadron cascade mechanism can produce dihadron correlation, but it can not give big
enough splitting parameters.
4)
3-particle correlations were investigated in the
central Au+Au collisions with AMPT, partoni
cascade will enhance the spilt of Mrch-like
cone.
Thanks for your attention
And
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