Jet quenching review I

HIM-6 June 2005HIM-6 June 2005

1

Su Houng Lee

Jet quenching review I Jet quenching review I

Main Review article; hep-ph/0406201

: Leading-particle suppression in high energy nucleus-nucleus collisions

A. Dainese, C. Loizides and G. Paic. Other Main References:

1. The Landau-Pomeranchuck-Migdal effect in QED, Baier, Dokshitzer, Mueller, Peigne, Schiff (BDMPS), NP B478 (1996) 577

2. Radiative energy loss of high energy quarks and gluons in a finite-volume quark gluon plasma, BDMPS, NPB 483 (1997) 291.

3. Gluon radiation off hard quarks in a nuclear environment: opacity expansion, U. Wiedemann, NPB 588 (2000) 303

4. Calculating quenching weights, Salgado, Wiedemann, PRD 68, 014008 (2003)


2

Ject quenching

An important parameter to be understood q̂


3

Section 2

Parton energy loss and collision goemetry

+My personal review

[email protected]@phya.snu.ac.kr

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4

Basics: fast charged particle scattering from scattering centers

10 Ep

2p

1p1x

2x

1q 2q

cx1

cx2cnx

nq

np

0110

11404 |)()()().....()()(

!| pxxAxxdxxAxxdn

ipS nnnn

n

n yyyy

223

3 )](exp[

)2()(

p i

ciiii

i q

xxiqxdixA

n

i i

iin

i i

iN q

xiq

ip

pdppS

122

)(1

12

300

0 ]exp[)(

h s

s

1

2,

2,

22,, ),,,(

iii

TiziiTizii

ppq

ppEpppEp

h

h

iE

pEp

iE

pEp

Tizi

Tizi

2

,2

2,

,

2,

,


5

n

i i

iin

i i

iN q

xiq

ip

pdppS

122

)(1

12

300

0 ]exp[)(

h s

s

22,1

2

2,

,

22,1

2,

,

4

1

2

1 ,

2

h

h

T

Tizi

T

Tizi

pEi

E

pEp

pi

E

pEp

n

i

n

inznziiziTiTi

n

iiiscatt zpzpizzpixqixqii

1

1

1)(,)1(,0)()1(,),(,

1)( )()( ssssss

22,1

21

221 )(

11

TpEpq

1. The high energy electron scatters successively on ordered scattering centers

2. As a consequence, the electron momenta are on shell

)1()1()( ...... sss zzz nn

hiE

pEp Ti

zi 2

2,

,


6

Basics: fast charged particle radiating from scattering centers

10 Ep

2p

1p1x

2x

1q 2q

cx1

cx2cnx

nq

np

3q

cx3

),,( Tz kkk

2

12

)exp(n

iii iBd

d

dI pa

E

pkuzzu TjTj

n

jiiiiscattrad

,1

12 ,)(

2


7

For QCD: Non-abelian nature

10 Ep

2p

1p1x

2x

1q 2q

cx1

cx2cnx

nq

np

3q

cx3

),,( Tz kkk

zkT

2

2

sizeQGPLq

qcenterscatteringdist

transfermediumT

,ˆ2

Two parameters characterizing the medium

cT L

LqLq

Lk

2

ˆ ˆ22Characteristic phase for coherent radiation

322

ˆ2

1ˆ

2 ,

2ˆ Lq

LqR

Lq c

c Change of variables typically to


8

Some famous result for QCD

10 Ep

2p

1p1x

2x

1q 2q

cx1

cx2cnx

nq

np

3q

cx3

),,( Tz kkk

c

2

for 12

1

for 2

lim

pa

c

cc

Rs

R

C

d

dI

2

0

ˆ lim LqCCdd

dIE RscRs

RR

aa


9

Section 3

Leading-particle suppression procedure


10

Actual step I: Factorization formula

2

/

0,

2

,,,,0

2 )(ˆ)()(

j

jjh

yjjt

jXab

bbaajbagqqjbayt

h

z

zD

dydp

dxfxfdzdxdx

dydp

d

j

ss


11

Step II: determination of parameters

0,2

b

0,

2

bz

For each parton


12

Different parameterization


13

Step III: determination of parameters


14

Step IV: determination of parameters


15

Section 4

Results


16

Nuclear modification factor in Au-Au at 200 GeV - i


17

Nuclear modification factor in Au-Au at 200 GeV - ii


18

Nuclear modification factor in Au-Au at 200 GeV - iii


19

Nuclear modification factor in Au-Au at 200 GeV - iv


20

Back to back correlation


21

Azimuthally-differential observables - i

Non negligible collective flow effect


22

Azimuthally-differential observables - ii


23

Nuclear modification factor in Au-Au at 62.4 GeV - i


24

Extrapolation to the LHC (5.5 TeV)


25

Section 5

Discussion


26

High-energy partons from the surface


27

High-energy partons from the surface


28

Energy loss saturation


29

Section 6

Conclusion


30

Energy loss saturation


31

SummarySummary

Documents

Jet quenching review I