Rapidity Asymmetry in d A Collisions

1
Jet Tomography of Hot Dense Matter
Jet
Xin-Nian Wang LBNL, June 25, 2003
2
Equation of States
F. Karsch 2001
QGP
Hadrons
Quarks(2x3x2x2)
Gluons(2x8)
3
Medium Response Function
4
Computed Tomography (CT)
Calibrated source
Jet Tomography Using Parton Jets
5
Jets Beams of quarks and gluons
6
EM Radiation
EM field carried by a fast moving electron
EM Radiation by scattering Interference between
initial and final state radiation
7
Electron Tomography
Classical radiation of a point charge (Jackson,
p671)
8
Two Limits
9
LPM Effect
10
Radiation in QCD Colors Make the Difference
k
11
DIS off Nuclei
12
Parton energy loss A twisted story
13
HERMES data
in Au nuclei
14
Expanding Medium
(GVW, GOW,Wiedemann)
15
Single spectra in AA collisions
16
Nuclear Modification Factor
17
Single hadron suppression
Talks by Hwa, Bass, Greco, Molnar
18
Di-hadron Spectra
19
Suppression of away-side jet
Df
20
Azimuthal Anisotropy
dihadron
Single hadron
21
Azimuthal anisotropy II
Talk by R. Lacey, S Voloshin
22
Partonic Energy Loss at RHIC
From RHIC data of AuAu Collisions
Initial Density about 30 times of that in a Cold
Au Nucleus
23
Energy Loss Is Partonic!
Could it be caused by hadronic absorption or
rescattering?
NO!
24
Parton Energy Loss 2

• (2) Centrality dependence

25
Parton energy loss (3)

• (3) PT Dependence

26
Parton Energy Loss (4)

• Large v2

early
late
Geometrical anisotropy is an early phenomenon!
27
Parton Energy Loss (4)

• (5) Same-side jet profile

Same-side jet cone remains the same as in pp
collision
PHENIX sees the same
Hadron rescattering will change the correlation
Between leading and sub-leading hadrons
28
Measuring Parton Energy Loss
29
Partonic energy loss (6) SPS
30
Summary

• Discovery of Jet Quenching proves that a strongly
  interacting dense matter is formed Opaque to
  jets
• Jet quenching is caused by partonic energy loss
• Dense matter at RHIC is 30 times higher than cold
  nuclei
• Collective behavior Hydrodyamic limit (talks by
  Csernai,Huovinen, Nonaka)
• It has to be QGP within QCD
• Jet tomography become useful and power tool for
  studying properties of dense matter

31
Hard Probes Collaboration
http//www-hpc.lbl.gov/
Hard Processes in pp, pA and AA

• Jet and high pt hadron
• Quarkonium
• Heavy Quarks
• Direct Photons
• DY

32
Parton Shadowing in Nuclei
33
Energy Dependence
Thermal absorption important at lower E
Detailed balance
Enke Wang XNW PRL87(01)142301
34
Medium Modified Fragmentation