Background introduction Model introduction Analysis method Results and discussions Conclusions

G.L. Ma, S. Zhang, YGM et al., Phys Lett B 641, 362 (2006) G.L.Ma, YGM, S. Zhang et al., arXiv:nucl-th/0608050, sub to PLB G.L.Ma, S. Zhang, YGM et al., arXiv:nucl-th/0610088, sub to APS

Y.G. Ma, G.L. Ma, S. Zhang, X. Z. Cai, H. Z. Huang et al.

Shanghai Institute of Applied Physics, CAS  

Two- and Three-particle Correlations in a Partonic Transport Model

(1(1

Di-hadron correlations

pT(assoc) > 2 GeV/c

pT(assoc) > 0.15 GeV/c

4 <

p T(t

rig)

< 6

GeV

/c

Soft associated Soft associated particlesparticles →→ enhancementenhancement

Hard associated Hard associated particles particles →→ suppressionsuppression

Associated particlesOn away side:

(2(2

Soft Associated particles on Away side (thermalization)

near sidenear side

away side

thermalization???thermalization???

What happens to a hard probe that traverses a colored medium? softened + broadened =?= thermalizedthermalized

(3(3

<pT > from away jets

<pT> from medium decay

SOFTENED BROADENED

Mach-like Structures

(4(4

NPA 774, 581 (2006)PRL 97, 052301 (2006)PHENIXPHENIX

Wake Effect or “sonic boom” Wake Effect or “sonic boom”

NPA 750, 121 (2005) Stöeckerhep-ph/0411315, hep-ph/0602183 Casalderrey-SolanaPLB 618, 123 (2005) J. RuppertPRC 73, 011901(R) (2006) T. RenkPRL 97, 062301(2006) A. K. Chaudhuri

PRC 72, 064910 (2005) ArmestoCorrelation of Jet with flowing medium Correlation of Jet with flowing medium

Cherenkov gluon radiation Cherenkov gluon radiation

PRL 96, 172302 (2006) Koch, Majumder, X.-N. WangPLB 630, 78 (2005) I. VitevNPA 767, 233 (2006) I.M. Dremin

Possible interpretations of Mach-like structuresΘemission= arccos (cs/c)

Θemission= arccos (1/n(p))

(5(5

AMPT model

(1) Default AMPT Model (2) Melting AMPT Model

a multi-phase transport model (by C. M. Ko and Z. W. Lin et al.)

(6(6

(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.

Mixing-event Technique

-1 0 1 2 3 4 50

2

4

6

8460

470

480

490

500

510

520

530

1/N

trig

dNch

/d

20-40%

20-40%

PT

trig 3-6GeV/c ,PT

asso 0.15-3GeV/c same event mix event

Background Subtracted signal

(7(7

correlationscorrelations from AMPT from AMPT((3<pT

trigger<6GeV/c ,0.15<pTassoc<3GeV/c)

(1) ▲melting version after hadronic rescattering(2) ● melting version before hadronic rescattering(3) ◆ default version after hadronic rescattering(4)★ default version before hadronic rescattering(5) ■ Star Data 0-5% (4-6)*(0.15-4)GeV/c factor=1.58

-1 0 1 2 3 4 5

0

1

2

3

4

5

6

7

8

AMPT 0-10%,(3-6) x (0.15-3)GeV/c melting version after hadronic rescattering melting version before hadronic rescattering default version after hadronic rescattering default version before hadronic rescattering Star Data 0-5% (4-6) x (0.15-4)GeV/c factor=1.58

1/N

trigd

N/d

(rad)

Au+Au 200GeV (0-10%)

(8(8

-0.10.00.10.20.30.40.50.60.70.8

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 1 2 3-0.1

0.0

0.1

0.2

0.3

0.4

0.5

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

10-20% (2.5-4)X(1-2.5)GeV/c melting version after hadron rescattering factor=1/1.75 melting version before hadron rescattering factor=1/1.75 default version after hadron rescattering factor=1/0.7 PHENIX data 10-20% faxtor=1.58

1/N

trigd

N/d

20-40% (2.5-4)X(1-2.5)GeV/c melting version after hadron rescattering factor=1/1.75 melting version before hadron rescattering factor=1/1.75 default version after hadron rescattering factor=1/0.7 PHENIX data 20-40% factor=1.58

1/N

trigd

N/d

(rad)

40-90% (2.5-4)X(1-2.5)GeV/c melting version after hadron rescattering factor=1/1.4 melting version before hadron rescattering factor=1/1.4 default version after hadron rescattering factor=1/0.7 PHENIX data 60-90% factor=1.58

1/N

trigd

N/d

0-10% (2.5-4)X(1-2.5)GeV/c melting version after hadron rescattering factor=1/4.2 melting version before hadron rescattering factor=1/4.2 default version after hadron rescattering factor=1/1.75 default version before hadron rescattering factor=1/1.75 PHENIX data 0-5% factor=1.58

1/N

trigd

N/dMach-like StructMach-like Struct

ures in AMPT mures in AMPT modelodel correlations in Au+Au 200GeV (correlations in Au+Au 200GeV (2.5<pT

trigger<4GeV/c ,1<pTassoc<2.5GeV/c)

Mach-like StructMach-like Structures in AMPT mures in AMPT modelodel correlations in Au+Au 200GeV (correlations in Au+Au 200GeV (2.5<pT

trigger<4GeV/c ,1<pTassoc<2.5GeV/c)

2 4 6 8 10 120.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

AMPT PT

trig 2.5-4(GeV/c),PT

associated 1-3.(GeV/c) melting version after hadronic rescattering default version after hadronic rescattering

exp. data PT

trig 2.5-4(GeV/c),PT

associated 2-3(GeV/c)split

ing

para

met

er D

(ra

d)

impact parameter b (fm)

D

(9(9

Is there conical flow?

away

near

Medium

mach cone

Mediumaway

near

deflected jets

hard-soft-corr + soft-bkgd.

soft-soft-corr in underlying event.

trigger softbkgd

assoc

assoc

3-4 GeV/c 1-2 GeV/c

flow modulated background:trig (1)2 2 1 trig

trig (2)2 2 2 trig

(1) (2)2 2 1 2

1 2 cos[2( )]

2 cos[2( )]

2 cos[2( )]

v v

v v

v v

3-particle correlation

Medium

away

near

di-jets

1

2

1

2

Three-particle correlations in AMPT

mix-event technique background subtracted

3-particle correlation signal

((2.5

<pTtri

gger <

4GeV

/c ,1

<

p Tas

soc <2

.5GeV

/c)

(10(10

The Npart dependences of three-particle correlations

3-particle correlation

density definition:

region

region

dd

ddddNd

21

2121

2

(11(11

What happens for p+p?

No Mach-cone behavior!

Correlations between forward- and mid-rapidity in d+Au collisions

STAR Preliminary

Mid-rapidity

Forward-rapidity

trig.

asso.

Parton cascade effect on 2- and 3- particle correlations

(1)Hadronic rescattering (1)Hadronic rescattering mechanism also can promechanism also can produce duce 2- and 3-particle 2- and 3-particle cocorrelations, but it can not rrelations, but it can not give big enough splitting give big enough splitting parameters. parameters. (2) Parton cascade mech(2) Parton cascade mechanism is essential for deanism is essential for describing the amplitude ofscribing the amplitude ofexperimental mach-like experimental mach-like structure.structure.

(12(12

Time Evolution of Mach-like Structures in AMPT model

At least a lifetime of partonic matter of At least a lifetime of partonic matter of 1.5 fm/c is needed for the birth of Mach-l1.5 fm/c is needed for the birth of Mach-like structures for 10mb. ike structures for 10mb.

parton cascade

hadronic rescattering

Lifetime

(13(13

-1 0 1 2 3 4 5 6

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

-1 0 1 2 3 4 5 6

0.0

0.4

0.8

1.2

1.6

2.0(a) melting AMPT modelwithout hadronic rescattering (10mb)central 0-10%, |y|<1.0(2.5-4.0)X(1.-2.5)GeV/c

1/N

trigd

Nassoc hadro

n/d

lifetime (fm/c)=0.5 1.0 1.5

(Rad)

melting AMPT modelwithout hadronic rescattering (10mb)central 0-10%, |y|<1.0(2.5-4.0)X(1.-2.5)GeV/c

(b)

1/N

trigd

Nassoc hadro

n/d

(Rad)

lifetime (fm/c)=2.0 2.5 3.04.0 5.0

Au+Au 200GeV (0-10%)

Partonic Mach-Like Shock Waves ?

(14(14

(15(15

pT dependences of Mach-like structures

(15(15

ppTT-dependent Mach-like -dependent Mach-like

shock wavesshock waves

?? ??√ ?? ?? ??

η dependences of Mach-like structures

PHOBOSPHOBOS

(16(16

1) Special trigger particles and associated particles2) System-size dependence including d+Au and p+p3) Δη and ridge- correlations

Conclusions and Outlook

1) Partonic Mach-like shock waves are born in the strong parton cascade and further developed in hadronic rescattering process.

2) Hadronic rescattering mechanism can produce similar correlation, but it can not give big enough splitting parameters and correlation areas.

3) The partonic shock waves are centrality-dependent ,pT-dependent and η-dependent.

(17(17

Outlook:Outlook:

Conclusions:Conclusions: