Effect of parton cascade to the medium

Hanlin LiIOPP, CCNU, Wuhan

Fuming LiuIOPP, CCNU, Wuhan

Xin-Nian WangLBNL, USA

Yan Zhu IOPP, CCNU, Wuhan

QNP, Beijing , September 21 － 26, 2009

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OUTLINE Introduction

Preliminary results Elastic energy loss Medium modification caused by jet

propagating

Conclusions and Outlook

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Introduction — jet quenching Jet quenching is a good probe of sQGP.

Suppression of High PT hadrons. It’s also important to study the modification of medium d

ue to jet propagation. Azimuthal angle correlation caused by jet medium int

eraction.

Several models: Putting a source current in hydrodynamic (Chaudhuri

and Heinz,2006); Markovian parton scattering (MPS) model (Charles B.

Chiu and Rudolph C. Hwa,2006). ……

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By now only elastic collisions are considered.

where and

Our approach — Parton cascade simulation based on Boltzmann Eq.

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Elastic collision rate:

Energy distribution of thermal parton:

Interaction amplitude:

Interval between successive collisions :

More useful formulae

Gyulassy and Wang,Nucl.Phys.B420,583

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Test our MC with numerical integration

Set jet moving along z-axis

Energy distribution of produce partons from single scattering

for different energy of jet E1.

Angle (theta=ATAN(pz/E) ) distribution of produce partons from single scattering

for different energy of produce particle.

E1=20GeV

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Elastic energy loss for qq collision

w/o. s.a.a.2 2

2

2| |

( )

s uM

t q

$

w. s.a.a.2

2

2 2

2| |

( )

sM

q q

$

Theory (X.N. Wang,Phys.Rept.280:287-371.)

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Modification of medium by propagating jett=2fm/c

Jet moves along z-axis.

r=sqrt(x2+y2)

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Modification of medium by propagating jett=4fm/c

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Modification of medium by propagating jett=8fm/c

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Azimuthal angle distribution —single scattering

Jet moves along z-axis.

Ф=ACOS(pz/sqrt(pz2+px2))

Double-peak appears in single scattering.

Azimuthal angle distribution is energy dependence.

pro.

Double-peak appears in single scattering.

Azimuthal angle distribution is energy dependence.

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Azimuthal angle distribution — multiple scattering

Double-peak at the early time as single scattering

Uniform distribution after enough time.

Double-peak disappears due to the interaction of associate partons.

t

=1

5fm

/c t

=4

fm/c

t=1

fm/c

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Conclusions and Outlook A parton cascade simulation has been construc

ed based on Boltzmann eq.. Elastic energy loss has been investigated. Strict

calculation shows a lower energy loss than that in previous work.

Cone structure of produced parton can be formed when jets propagate in the medium.

The azimuthal angle distribution of produced partons depends strongly on their energy and the medium size.

More realistic medium will be used. Inelastic collision(2 3) will be included.

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ThanksThanks

for your attention!for your attention!

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Azimuthal angle correlation —single scattering

Jet move along z-axis.

Ө=ATAN(pz/E)

Azimuthal correlation is energy dependence.

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Multiple scattering exclude scattering among thermal partons