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Jet Tomography and Particle Correlations
in Heavy-Ion CollisionsBarbara Betz
Thanks to: Miklos Gyulassy, Jorge Noronha, Dirk Rischke, Giorgio Torrieri
Phys. Rev. C 79, 034902 (2009); Nucl. Phys. A 830, 777c (2009); Phys.Rev. Lett. 105, 222301 (2010); arXiv:1012.4418 [nucl-th]
arXiv:1102.5416 [nucl-th]
2
HIC Facilities
initial state
pre-equilibrium
expanding fireball
hadronization
hadronic phaseand freeze-out
S. Bass, Talk Quark Matter 2001
RHIC
FAIR
LHC
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
RHIC, BNL: 2000 – … p+p, d+Au, Cu+Cu,
Au+Au LHC, CERN: 2008/9 - … p+p, Pb+Pb FAIR, GSI: ~2016 - … accelerates ions from p
to U
? ?
3 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Tomography and Correlations
What can be extracted about medium proper-ties?
What do conical correlations tell us?
What is the role/impact of fluctuating initial
conditions?Test sensitivity of azimuthal dependenceof single and dihadron nuclear
modification factors
4 < pTtrigger < 6 GeV/c
0.15 < pTassoc < 4 GeV/c
STAR, Nucl. Phys. A 774, 129 (2006)
PHENIX, Phys. Rev. Lett. 105, 142301 (2010)
The Medium
Initial Conditions
4
2 Major RHIC Results
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
5
Reproducing the elliptic flow v2
P. Romatschke and U. Romatschke, Phys. Rev. Lett. 99,172301 (2007)
Medium behaves like an almostideal fluid
/s
BNL press release, April 18 2005.
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Particles don‘t interact,
expansion independent
of initial shape
Particles interact,expansion
determined by density gradient
„dust“ fluid
Data can be described by hydrodynamics
with small
Fluid-like Medium
6
Jet Quenching• Like in medicine, hard probes can be
used to investigate the medium properties
• If created matter is opaque, a jet depositing its energy should eventually disappear jet suppression
STAR, Phys. Rev. Lett. 91 (2003) 072304
4 < pTtrigger < 6 GeV/c
pTassoc > 2 GeV/c
What can the energy lost tell us about the medium properties
and the initial conditions?
Trigger particle
University Wuppertal, “Schul-Vorlesungen zur Physik”
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
7
The Medium
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
8 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Jets in HIC I
By observation: Confirm fast
thermalization Study EoS of the fluid
Mach cone angle sensitive to EoS
Can energy lost by jets tell us something about medium properties?
IF the medium behaves like a fluid:
Mach cones have to occur because of
fluid dynamics
4 < pTtrigger < 6 GeV/c
0.15 < pTassoc < 4 GeV/cAu+Au / p+p
= 200 GeVs
PHENIX, Phys. Rev. C 77, 011901 (2008)
9
Jets in HIC II
STAR, Nucl. Phys. A 774, 129 (2006)
Reflect interaction of jet with medium
• Redistribution of energy to lower pT-particles
• Re-appearance of the away-side for low and intermediate pT
assoc
H. Stöcker, Nucl. Phys. A 750, 121 (2005), J. Casalderrey-Solana et al. Nucl. Phys. A 774, 577 (2006)
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
10
Experimental Studies
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Many more studies: path-length dependence, centrality dependence, energy
dependence11
STAR, Phys. Rev. C 82, 024912 (2010)see also PHENIX, Phys. Rev. C 77, 011901 (2008)
Position of away-side
peaks does not change
strongly with pTassocNot due to
Cherenkov gluonradiation
What happens to larger pT
trigger?
Jet - Studies in HIC I
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
A. Sickeles [PHENIX], Eur. Phys. J. C 61, 583 (2009); PHENIX, Phys. Rev. Lett. 97, 052301 (2006); J. Jia, Eur. Phys. J. C 62, 255 (2009)
12
Some caveats
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
13
Background Subtraction
How can one proof/disproof
the two-source model?
J. Ulery [STAR], PoS LHC07, 036 (2007)
D. d’Enterria and BB., Springer Lecture Notes (2008)
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Assumption (Two-source model) :
No correlations between flow anisotropy
and jets
ZYAM (Zero Yield At Minimum)
Subtraction of:estimated elliptic flow modulatedbackground
can leads to:double peaked structure
Background:Particle
correlation from elliptic flowOther methods
A. Sickles et al, Phys. Rev. C 81, 014908 (2010)STAR, arXiv: 1102.2669 [nucl-ex]
14
3-Particle Correlations
J. Ulery [STAR], Int. J. Mod. Phys. E 16, 2005 (2007)
ptrigT=3 – 4 GeV, passoc
T=1 – 2 GeV Three-particle correlations
seem to corroborate Mach cone idea
- What’s the effect of ZYAM?
- No agreement with 3-particle cumulant method
C. Pruneau, Phys. Rev. C 79, 044907 (2009)
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Deflected jet
Mach Cone
ptrigT>3 GeV, passoc
T=1 – 2 GeV
C. Pruneau, Talk at the Workshop on ‘Critical Asessment of Theory and Experiment on Correlations at RHIC’, BNL, February 2009
15
Theoretical Approach
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
16
Modelling of Jets
STAR, Phys. Rev. Lett. 95, 152301 (2005)
residue of energy and momentum given by the jet
• Assumption of isochronous/isothermal freeze-
out
• No interaction afterwards
mainly flow driven
Conversion into particles Freeze-out:
Jets can be modelled using (ideal) hydrodynamics:
e+p v.
Medium created in a HIC can be described using hydrodynamics
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
17
The Static Medium
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
18
Stopped Jet IApplying a static medium and an ideal Gas EoS for massless
gluons
Assume: Near-side jet is not modified by mediumMaximal fluid
response
Jet decelerating from v=0.999according to Bethe-Bloch
formalism
a=-1.36 GeV/fm
Simplest back-reaction from the medium
Bragg Peak
adjusts path length
BB et al., Phys. Rev. C 79, 034902 (2009)
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
19
Stopped Jet II
Mach cone forsound waves Diffusion
wake
dE dM GeV(0) v (0) 1.5
dt dt fm= =
t=4.5/v fmdE GeV dM GeV
(0) 1.5 (0) 0dt fm dt fm
= =
BB et al., Phys. Rev. C 79, 034902 (2009)
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
20
Stopped Jet III
Diffusion wake causes peak in jet direction
Normalized, background-subtracted isochronous Cooper-Frye at mid-rapidity
Energy Flow Distribution
Assuming: Particles in subvolume will be emitted into the same direction
pT = 5 GeV
BB et al., Phys. Rev. C 79, 034902 (2009)
Any conclusions about deposition mechanism???03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara
Betz
21 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
The Expanding Medium
22
Expanding Medium I
Consider different jet paths
b=0
• Apply Glauber initial conditions and an ideal Gas EoS for massless gluons• Focus on radial flow contribution
Experimental results based
on many eventsA. K. Chaudhuri, Phys. Rev. C 75, 057902
(2007) ,A. K. Chaudhuri, Phys. Rev. C 77, 027901
(2008)
• Two-particle correlation (Tfreeze-out < Tcrit = 130
MeV):
near-side jet
dE/dt = 1 GeV/fm
Jet 150
Etot = 5 GeV
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
23
Expanding Medium IIEtot = 5 GeV
broad away-side peak double peaked structure
due to non-central jets
pTtrig = 3.5
GeV
PHENIX, Phys. Rev. C 77, 011901 (2008)
vjet =0.999
BB et al., Phys. Rev. Lett. 105, 222301 (2010)
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
24
Expanding Medium IIIEtot = 10
GeV
Strong impact of the Diffusion wake
broad away-side peak double peaked structure
Causes smaller dip for pT=2 GeV
pTtrig = 7.5
GeV
6 < pTtrigger < 10
1.5 < pTassoc < 2.5
f
Yield
Path length dependence Centrality dependence03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara
Betz
STAR, Phys. Rev. C 82, 024912 (2010)
BB, arXiv:1012.4418[nucl-th]
25
Expanding Medium IV
Conical emission angle also appears for subsonic jets
Not a Mach cone
Considering a bottom quark (M=4.5 GeV), propagating at vjet < cs
(energy-momentum deposition scenario) pTassoc = 2.0
GeV
Cu+Cu: Similar away-side shoulder width, double-peak structure reappars for pT
assoc = 3 GeV
PHENIX, PRL98, 232302 (2007)
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
BB et al., Phys. Rev. Lett. 105, 222301 (2010)
26
Some more caveats
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
27
Hot Spots ICan fluctuating initial condition explain the 2+3-particle
correlations?Takahashi et al, PRL 103, 242301 (2009)
F. Grassi, Talk at the Glasma Workshop, BNL, May 2010
R. Andrade et al., J. Phys. G 37, 094043 (2010)
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
28
Hot Spots IICheck with one single hot
spot
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Au, De/e0 = 2
29
Hot Spots III
Can hot spots explain everything?
There is a superposition of jets and fluctuating initial conditions
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
pTassoc= 2.0 GeV pT
trig = 8.0 GeV
pTtrig = 3.5
GeV
Both lead to double-peak structure
Coalesced peak only for jet events
Heavy quark jets need to be studied
BB, arXiv:1012.4418 [nucl-th]
30
Heavy-flavor results
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
e-h correlations from heavy-flavordecay show a double-peak
structure on the away-side
Clear indication that the signal is not just background fluctuation
A. Adare et al. [PHENIX], arXiv: 1011.1477[nucl-ex]
31
Why v3 deformations cannot be the whole story
ptrigT=3 – 4 GeV, passoc
T=1 – 2 GeV
What are the consequences of triangular flow?
The latter case should not be subtracted!
v3 could be due to initial conditions (hot spots)
OR due to a jet traversing the medium
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
- Correlation in Df1-Df2
Df1/2 120°
- No correlation in Dh1-Dh2
B. Alver et al., Phys. Rev. C 81, 054905 (2010)
120°
Shock front??
~ 120
J. Ulery [STAR], Int. J. Mod. Phys. E 16, 2005 (2007)
B. Alver, Talk at the Glasma Workshop, BNL, May 2010
32
Fluctuating Initial Conditions
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
33 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Initial Conditions
Studying heavy-ion collisions requires a good understanding of the role of the initial conditions:
- Glauber model: incoherent superposition of p+p collisions
- Color Glass Condensate (CGC): saturation effects are included
They differ:
- initial temperature gradients- initial high-pT parton distribution
- distance travelled by each parton
Leads to a different opacity estimate
B. Alver, Talk at the Glasma Workshop, BNL, May 2010
CGC
Glauber
L. McLerran, Talk at a the CP Violation Workshop, BNL, April 2010
34 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Opacity of the Medium Exploring the properties of the
strongly-coupled sQGPjet quenching: signal for creation of opaque matter
(QGP)
S. Bass et. al., PRC 79 (2009), 024901
defined via:
Current description commonly based on pQCD though medium is supposedly sQGP
D. D’Enterria, Lect. Notes Phys.785 (2010), 285
S. Bass et. al., PRC 79 (2009), 024901
35 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Caveat
pQCD descriptions disagree in their prediction of the azimuthal anisotropy of high-pT hadrons, characterizing
due to v2=v2(l)
v2 is sensitive to the path lengthdependence of energy loss, scaling as dE/dx ~ lz:
z=1 : pQCD
z=2 : AdS/CFT (on-shell partons)
z>2 : AdS/CFT (off-shell partons)
M. Gyulassy et. al., PRL 85 (2000), 5535
S. Gubser et. al., JHEP 0810 (2008), 052;P. Chesler et.al., PRD 79 (2009) 125015
36
Energy-Loss Mechanisms
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
A. Adare et al, Phys. Rev. Lett. 105, 142301 (2010)
First investigation of v2(Npart) and RAA(Npart) for pT > 5 GeV hadrons is based onJ. Jia et. al., PRC 82 (2010),
024902
simple jet absorption model
Once RAA(Npart=350) ~ 0.18 for 0-5% p0 data
- pQCD-like energy loss fails to reproduce v2(Npart)
- AdS/CFT-like energy loss describes data for CGC initial conditions
pQCD-like AdS/CFT-like
37
Generic Energy Loss Model
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
38
Generic Energy Loss Model
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Choosing an ansatz for the energy loss
t0 = 2fm, one can determine the RAA(Npart), vn(Npart)
P: momentum of the jet(s)
a,z: parameters controlling the jet-energy and path-length dependence
k: being fixed thus that RAA(Npart=350) ~ 0.18 for most central data and considering Bjorken expansion via
CGC/KLN: H. Drescher et. al., PRC 76 (2007) 024905
Glauber: B.Betz et.al., arXiv:1102.5416 [nucl-th]
39
RAA and v2
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
z=1 z=2Having fixed k for
RAA(Npart=350) ~ 0.18
RAA(Npart) can be
reproduced z=1: v2 not reproduced
z=2: v2 reproduced for CGC initial cond.
B.Betz et.al., arXiv:1102.5416 [nucl-th]
a=0.3
Small fluctuations for
RAA(Npart)
large fluctuations for
v2(Npart)Not straightforward
to distinguish between initial conditions
40 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
RAA vs. IAA, and vn vs. vnIAA
Extend to dijet analysis,
but considering kaway = k
In contrast to Jia’s model, we
fit the RAA vs. IAA
vn vs. vnIAA:
- clear shift between Glauber and CGC model
- saturation effect for larger z
B.Betz et.al., arXiv:1102.5416 [nucl-th]
J. Jia et.al., arXiv:1101.0290 [nucl-th]
It is necessary to alwaysdetermine the mean andthe with of a correlation!
41
Higher Harmonics
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
z=1 z=2
- v3≠0 event-by-event,
- v4 similar for average and event-by-event initial conditionsNot suitable to
distinguish between
Glauber and CGC
initial conditions
Higher harmonics are more sensitive to local gradients, but also to event-
by-event fluctuations larger v3,4 fluctuations
B.Betz et.al., arXiv:1102.5416 [nucl-th]
42
Path-length dependence
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Study the path-length dependence at b=8fm:
- Once RAA is fixed via k,
- sensitivity remains mostly for v2 and v3
saturation effect occurs for larger z
described by AdS/CFT
off-shell partonsS. Gubser et. al., JHEP 0810 (2008), 052;P. Chesler et.al., PRD 79 (2009) 125015
Measurement of virtuality in jet-photon collisions & v2,3 could lead to signature of AdS/CFT dynamics & microscopic mechanism of energy loss.
B.Betz et.al., arXiv:1102.5416 [nucl-th]
Summary „Conical“ signal can be created (general effect):
by averaging over deflected wakes created by jets.
Structure cannot directly be related to EoS, but is a measure for the flow
even for subsonic jets
Necessary to study heavy-flavor tagged jets.
43
„Conical“ correlations could arise from multiple non-Mach sources
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Investigated higher Fourier harmonics of jet quenchingShowing that they are remarkably insensitive to theGlauber and KLN/CGC model initial conditions
Studied the path-length dependence for larger exponentsa saturation effect occurs for larger exponentsfavoring an AdS/CFT energy loss
44
Backup
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
45
Investigation of path length dependence:Double-peaked structure becomes
more
pronounced out-of-plane
A. Sickeles [PHENIX], Eur. Phys. J. C 61, 583 (2009)
Jet - Studies in HIC
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Could be due to deflection
46
Centrality dependence:
double-peaked structure for central collisions
one peak structure for very peripheral collisions
PHENIX, Phys. Rev. Lett. 97, 052301 (2006)
J. Jia, Eur. Phys. J. C 62, 255 (2009)
Jet - Studies in HIC
Energy Scan:
double-peaked structure occurs at about the same angle for different collision energies Mach cone???03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara
Betz
47
Stopped Jet • Jet stops after t=4.5/v
fm
dE GeV(0) 1.5
dt fmdM GeV
(0) 0dt fm
=
=
dE GeV(0) 1.5
dt fmdM GeV
v (0) 1.5dt fm
=
=
Vorticity conservation
tFO=4.5/v fm
tFO=6.5/v fm
tFO=8.5/v fmDiffusion wake still
present
BB et al., Phys. Rev. C 79, 034902 (2009)
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
48
Stopped Jet
tFO=4.5/v fm
tFO=6.5/v fm
tFO=8.5/v fm
Diffusion wake causes peak in jet direction
Larger impact of thermal smearing
BB et al., Phys. Rev. C 79, 034902 (2009)
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
49 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Still influence of
diffusion wake
• Transverse momentum deposition:
from explosion of
matter
t=4.5/v fm
L TdM dM1=
dt 4 dt
TdMdE=
dt dt
Vorticity conservation
Punch – Through Jet
BB et al., Phys. Rev. C 79, 034902 (2009)
50
BAMPS: Boltzmann Approach of MultiParton Scatterings
A transport algorithm solving the Boltzmann equations for on-shell
partons with pQCD interactions
C. Greiner, Talk at the Opening Symposium of the JET Collaboration, Berkeley, June 2010
Box scenario, no expansion, massless Boltzmann gas interactions, 2 -> 2
The shock front (Mach front) gets broader and vanish with more dissipation03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara
Betz
Mach Cones in Transport
51 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Different Jet-Energy Loss Modells
52 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Modelling Jets using …
Conclusion about Mach cones?
pQCD
AdS/CFT
P. Chesler and L. Yaffe, Phys. Rev. D 78, 045013 (2008)
R. Neufeld et al, Phys. Rev. C 78, 041901 (2008)
Strongly-coupled theory
Pointing vector perturbation
Momentum density perturbation
Energy density perturbation
Energy density perturbation
Weakly-coupled theory
v=0.75
v=0.99955
53 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Non-Mach correlations caused by Neck region
Jets in AdS/CFT
J. Noronha et al., Phys. Rev. Lett. 102, 102301 (2009)
54 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Heavy Quark Jets
55 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Heavy Quark JetsCompare weakly and strongly coupled models using heavy punch-
through jet
pQCD: Neufeld et al. source for a heavy quark
AdS/CFT: Stress tables with/s=1/(4 ) R. Neufeld et al, Phys. Rev. C 78, 041901 (2008)
pT = 3.14 GeV
BB et al., Phys. Lett. B 675, 340 (2009)
No Mach-like peaks:AdS/CFT: Strong influence of the Neck region
Static medium and isochronous freeze-out needed for comparison
t=4.5/v fmS. Gubser et al, Phys. Rev. Lett. 100, 012301 (2008)
BB et al., Phys. Lett. B 675, 340 (2009)
J. Noronha et al., Phys. Rev. Lett. 102, 102301 (2009)
56
Expanding Medium
Comparing different deposition scenarios, one sees that„cone“ angle approximately the same for different deposition
scenarios
pTassoc = 2.0 GeV: No double-peaked structure for pure energy
deposition scenario due to thermal smearking
pTtrig = 3.5
GeV pTassoc = 3.0
GeVpT
assoc = 2.0 GeV
vjet =0.999
BB et al., arXiv: 1005.5461
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
57
Initial Fluctuations IP. Sorensen J. Phys. G 37, 094011 (2010), B. Alver et al., Phys. Rev. C 81, 054905 (2010)
Glauber initial conditions:
due to symmetry, odd Fourier components vanish
higher Fourier components may occur
Fluctuating initial conditions:B. Alver, Talk at the Glasma Workshop, BNL, May 2010
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
58
Initial Fluctuations II
B. Alver et al., arXiv: 1007.5469
B. Alver et al., Phys. Rev. C 81, 054905 (2010), B. Alver et al., arXiv: 1007.5469H. Petersen et al., arXiv: 1008.0625
v3 not negligable small
• v3 is extensively studied
Calculating v3 using a viscous hydro model with initial conditions deformed
according to the eccentricities from a Glauber and a KLM (CGC) model
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
59
Insensitivity of higher vn‘s
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Why are the vn‘s at high-pT so insensivite to initial conditions while the vn‘s of soft particles are?
- viscous forces are driven by local gradients- jet absorption is driven by global differences in the
integrated
These two effects are different, especially event-by-event- Glauber and CGC in. cond. are tuned to reproduce the observed multiplicites
<T> is similar, even if local gradients of T are different
Hydrodynamics and tomography lead to very different results.
60
Flow Subtraction
Subtraction of v2 and v3
leads to double-peak structure
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Jun Xu et al, Phys. Rev. C 83, 021903 (2011)
Subtraction of larger vn only
leads to one broad away-side
peak
4 < pTtrigger < 6 GeV/c
0.15 < pTassoc < 4 GeV/c
STAR, Nucl. Phys. A 774, 129 (2006)
sim
ilar
shap
e
61
(2+1)d correlations
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
H. Agakishiev et al. [STAR], arXiv:1102.2669[nucl-ex]
2 trigger, opposite to each other
+ 1 associated jetStill using ZYAM
Trigger particle
Trigger particle
It needs to be shown that jet quenching results can be reproduced
for larger pTassoc
Structure on the away-side
1.5 GeV < pTassoc < pT
trig1
5 < pTtrig1 < 10 GeV/c
pTtrig2 < 4 GeV/c
62 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Full Jet Reconstruction I
J. Putschke, Talk at RHIC and AGS Users Meeting 2009
Full jet reconstruction
questions ZYAM
63 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Full Jet Reconstruction II
No apparent v2 modulation in jet-hadron vs. di-hadron correlations
J. Putschke, Talk at RHIC and AGS Users Meeting 2009
64 03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Full Jet Reconstruction III
Jet-hadron away-side significantly narrower
J. Putschke, Talk at RHIC and AGS Users Meeting 2009
65
Generic Energy Loss Model
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
n ~ 6: spectral index
K = k (1-a)
Nuclear modification factor
with
TAA : Glauber
TAA = r2/ P02 : CGC
H. Drescher et. al., PRC 76 (2007) 024905
66
Generic Energy Loss Model
03/04/10 Nuclear Theory and RIKEN seminar, BNL Barbara Betz
Having fixed k, the harmonics can be calculated
B. Alver, Talk at the Glasma Workshop, BNL, May 2010
determining the angle with the reaction plane
and the Fourier density components are given by