Modification of Jet Properties
in Heavy Ion Collisions
Wolf Gerrit Holzmann
(Nuclear Chemistry, SUNY Stony Brook)
for the
Collaboration
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Outline
Introduction
• General Motivation
• Heavy Ion Collisions
Jet Observables & What they tell us
• Jets in h+h Collisions
• Jets in Au+Au Collisions
• Modification of Jet Topologies in Au+Au
Summary
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
General Motivation
Phase Diagram for Nuclear Matter
Probe experimentally via Heavy Ion Collisions!
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Heavy Ion Collisions at RHIC:
√ High Energy-density Matter Created in
Au + Au Collisions
ε ~ 50 - 100ε0
√ Rapid Equilibration is Achieved
Large Pressures ► large measured v2
√ Inferred Hadronization Temperature is
Consistent
T ~ 176 MeV,
μ ~ 40 MeV
The Consequences of this High-density
Should be manifestly Present
Jets are Remarkable Probes for this High-density Matter
• Auto-Generated
• Calibrated
• Calculable (pQCD)
• Accessible statistically via correlations in
4 Au+Au
Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Jets in h+h Collisions
 near
Fragmentation:
z
phadron
p parton
 far
Rcone
near-side
parton
away-side
kT
Δφ
jT
hadron
hadron
j y
kTy
 Near
 p sin


pT
z
parton
2
2
 Fa


r
Near
h
dAzimuthal
Dh0/ c
pp
Correlations
Carry
Invaluable
2
2 d Information
 K   dxa dxb f a ( xa , Q ) f b ( xb , Q )
( ab  cd )
2
ˆ
5 z c
dyd pT
dt
abcd Pertaining To Jet Properties.
Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Jets in Au+Au Collisions
Fragmentation:
z
Rcone
phadron
p parton
 far
Induced Gluon Radiation
~ collinear gluons in cone
“Softened” fragmentation
k
2
T
E
 far
  g ( x) dx
 x  g ( x) dx
I. Vitev, nucl-th/0308028
Gyulassy et al., nucl-th/0302077
The Predicted Influence of the
Medium is Specific.
nchin jet : increases
zin jet : decreases
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Calibrated Signal
C()
Adler et al., PRL90:082302 (2003), STAR
1.3
2.0 < pT < 3.0 (GeV/c)
1.2
PHENIX Preliminary
d+Au
1.1
1.0
near-side
away-side
0.9
0
30
60
90
120
150
180
deg.
Distinct Di-jet peaks observed for p + p and d + Au
Extracted Di-jet properties serve as baseline
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Conditional-Yields
conditional yields are corrected for
-acceptance & efficiency, and are reported in
the PHENIX h-acceptance ( | h | < 0.35 ).
Area under curve
Total Area
fraction of pairs
that are correl.
jet pairs
correlated jet-pairs over
combinatoric background
n jet  pairs
ntotal pairs

ntotal pairs d
ntrig d  nassoc d
ncorrel pairs
ntrig d  nassoc d

 nassoceff corr 
ncorrel pairs
ntrig d  nassoc d
ncorrel pairs
ntrig
conditional 8yield
Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Calibrated Signal - d+Au
ncorrel pairs
ntrig
n jet  pairs
ntotal pairs
Expected Yield Dependence
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
2.5  pTLH  4.0 GeV/c
Measured Correlation
Functions in Au+Au
10-20%
05-10%
Cent: 0-5%
1.0  pTAM / B  2.5 GeV/c
40-60%
20-40%
1.1
1.0
Associated
Mesons
C
0.9
PHENIX Preliminary
0.8
1.1
1.0
Associated
Baryons
0.9
0.8
0
40
80
120
160 0
40
80
120
160 0
40
80
120
160 0
40
80
120
160 0
40
80
120
160
deg.)
Au + Au Correlation Functions are Dominated by Harmonic and Jet
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Correlations
Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Decomposition of Correlation
Function
It is necessary to decompose the
correlation function to obtain
reliable jet yields and jet
properties
Correlation Function
C   
 Harmonic Jet Function 
 a0  H     J    


C     a0 H    
J     
a0
Jet Function
Wolf G. Holzmann, DIS04
J  min   0
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Wednesday, April 14 2004
Correlations relative to
Reaction Plane
Correlation Function
Jet Function
SIMULATION
Out-of-plane
In-plane
Correlations Relative to
the reaction plane are
used as a constraint
Harmonic
J. Bielcikova, S.Esumi, KF, S.Voloshin, and J.P.Wurm,
nucl-ex/0311007, to appear in PRC(R).
Wolf G. Holzmann, DIS04
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Wednesday, April 14 2004
Is there Broadening of the Away
Side Jet in Au+Au Collisions?
Fragmentation:
z
phadron
p parton
Rcone
Associated charged hadrons
and mesons show centrality
dependent broadening of
away-side jet
d+Au
kT2
E
  g ( x) dx
 x  g ( x) dx
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Centrality Dependence of Cond.
Jet Yields
Escaping Jet
“Near Side”
Suppressed
Jet
“Away Side”
• Charged hadron yields show
apparent away-side suppression
• Hadron yields dominated by
Mesons
• Similar near- and away-side
for associated baryons.
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Centrality Dependence of Baryon
to Meson Ratios
The Observed baryon to meson ratio is
higher for away-side jets
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Di-Jet Tomography
X.N. Wang
Out-plane
In-plane
dE
dx
l2
Angular Dependent Jet
Modification should be
an important observable
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Di-Jet Tomography
pTtrig=4.0-6.0 GeV/c, |h|<1.0
2.0<pTassoc<pTtrig
pTtrig=2.5-4.0 GeV/c, |h|<0.35
1.0<pTassoc<2.5 GeV/c
0.006
STARpreliminary
Preliminary
STAR
Jet-pair Distributions
Au+Au s  200 GeV
<nab>/<na><nb>
20-60%
20-60%
20-60%
20-60%
PHENIX Preliminary
Centrality 20 - 40 %
0.004
color scheme:
in-plane out-of-plane
0.002
0.000
0
20
40
60
80
100
120
140
(deg.)
Away-side jet is suppressed and broadened
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
160
180
Gyulassy et al., nucl-th/0302077
Further Test for
Modification
Nuclear Modification Factor
RAA 
Yield in Au  Au Events
A  B  Yield in p  p Events 
nchin jet : increases
zin jet : decreases
no effect 
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Single Particle Distributions
Au + Au Experiment
Final Data
d + Au Control Experiment
Preliminary Data
Null Control
Cronin effect (initial state effect) dominates in d+Au
High-pT Jet Suppression dominate in Au+Au.
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Summary and Conclusions:
 Jets observed and studied in HI Collisions via Angular Correlations
 Can measure Yields, jet-shapes (jT,kT) from correlation functions
 Jet quenching manifested via
 suppression of conditional yields
 away-side broadening
 suppression in inclusive pT distribution
 angular away-side suppression
The next frontier:
Detailed Studies:
 Di-Jet Tomography
 Flavor Composition of Jets
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Brazil
China
University of São Paulo, São Paulo
Academia Sinica, Taipei, Taiwan
China Institute of Atomic Energy, Beijing
Peking University, Beijing
France
LPC, University de Clermont-Ferrand, Clermont-Ferrand
Dapnia, CEA Saclay, Gif-sur-Yvette
IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, Orsay
LLR, Ecòle Polytechnique, CNRS-IN2P3, Palaiseau
SUBATECH, Ecòle des Mines at Nantes, Nantes
Germany University of Münster, Münster
Hungary Central Research Institute for Physics (KFKI), Budapest
Debrecen University, Debrecen
Eötvös Loránd University (ELTE), Budapest
India
Banaras Hindu University, Banaras
Bhabha Atomic Research Centre, Bombay
Israel
Weizmann Institute, Rehovot
Japan
Center for Nuclear Study, University of Tokyo, Tokyo
Hiroshima University, Higashi-Hiroshima
KEK, Institute for High Energy Physics, Tsukuba
Kyoto University, Kyoto
Nagasaki Institute of Applied Science, Nagasaki
RIKEN, Institute for Physical and Chemical Research, Wako
RIKEN-BNL Research Center, Upton, NY
USA
Rikkyo University, Tokyo, Japan
Tokyo Institute of Technology, Tokyo
University of Tsukuba, Tsukuba
Waseda University, Tokyo
S. Korea Cyclotron Application Laboratory, KAERI, Seoul
Kangnung National University, Kangnung
Korea University, Seoul
Myong Ji University, Yongin City
System Electronics Laboratory, Seoul Nat. University, Seoul
Yonsei University, Seoul
Russia
Institute of High Energy Physics, Protovino
Joint Institute for Nuclear Research, Dubna
Kurchatov Institute, Moscow
PNPI, St. Petersburg Nuclear Physics Institute, St. Petersburg
St. Petersburg State Technical University, St. Petersburg
Sweden Lund University, Lund
12 Countries; 58 Institutions; 480 Participants*
*as of January 2004
Wolf G.
Abilene Christian University, Abilene, TX
Brookhaven National Laboratory, Upton, NY
University of California - Riverside, Riverside, CA
University of Colorado, Boulder, CO
Columbia University, Nevis Laboratories, Irvington, NY
Florida State University, Tallahassee, FL
Florida Technical University, Melbourne, FL
Georgia State University, Atlanta, GA
University of Illinois Urbana Champaign, Urbana-Champaign, IL
Iowa State University and Ames Laboratory, Ames, IA
Los Alamos National Laboratory, Los Alamos, NM
Lawrence Livermore National Laboratory, Livermore, CA
University of New Mexico, Albuquerque, NM
New Mexico State University, Las Cruces, NM
Dept. of Chemistry, Stony Brook Univ., Stony Brook, NY
Dept. Phys. and Astronomy, Stony Brook Univ., Stony Brook, NY
Oak Ridge National Laboratory, Oak Ridge, TN
University of Tennessee, Knoxville, TN 21
Vanderbilt
University, Nashville,
TN
Wednesday,
April 14 2004
Holzmann,
DIS04
BACKUP
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Elliptic Flow
Low Energy:
Squeeze-out
t expan
R
~
cS
t pass ~
2R
 0 0
High Energy
In-plane
t expan ~
R
cS
t pass ~
2R
 0 0
Large Energy Density lead to pressure gradients  flow
Probes the global features of the collision,
Can serve to constrain the EOS
Tells us something about the pressure buildup -> barometer
Measure through correlations:
• reaction plane
• 2-particle correlations
• cumulants
dN
~ 1  2v1 cos( )  2v2 cos(2 )
d
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
Correlation Function Method
Wang et al.,
PRC 44, 1091 (1991)
Lacey et al.
PRL 70, 1224 (1993)
C ( ) 
N real ( )
N mixed _ events ( )
First Application of the Azimuthal Correlation Technique24at RHIC
Wolf G. Holzmann, DIS04
Wednesday, April 14 2004
& Correl.- Functions
jTjT
, k,kT
T & Correlation Functions
jT and kT are 2D vectors. We
measure the mean value of its
projection into the transverse
plane |jTy| and |kTy| .
1.2
1.1
jTy
2

 k 2T 
C(
| k Ty | 
 near
 pT sin

ztrig kTy 
pT
2 xh
sin
1.0
near
far
0.9
0.8
0
20
40
60
80
100
120
140
160
180
deg.)
2
2
2
2  near
 far  (1  xh ) sin


xh = pT,assoc / pT,trigg
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Wolf G. Holzmann, DIS04
Wednesday, April 14 2004