heavy ions collisions (results and questions) part ii
DESCRIPTION
Heavy Ions Collisions (results and questions) PART II. Anatoly Litvinenko. [email protected]. 1. Some estimations. 2. Particle ratios and s tatistical models. 3. 3. Particle (hadrons) spectra. A Iordanova (for the STAR Collaboration) ; J. Phys. G35 , p. 044008 , (2008. 4. 4. - PowerPoint PPT PresentationTRANSCRIPT
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Heavy Ions CollisionsHeavy Ions Collisions(results and questions)(results and questions)
PART IIPART II
Anatoly Litvinenko
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Some estimations
;ΔyτπR=ΔV
;yΔ1800) - 900(yΔdy
dNNΔ
Form2
==
)8)(1/fm - (4=1600)/200 - (800=)τ)/(πRdy
dN(=ΔV/NΔ)fm/(n 3
Form2=1 3
fm 0.035) - (0.07=λ mb 30=σ
1/nσ=λ
⇒
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Particle ratios and sParticle ratios and statistical modelstatistical models
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Particle (hadrons) Particle (hadrons) spectraspectra
A Iordanova (for the STAR Collaboration);J. Phys. G35, p.044008, (2008
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:
elliptic flow hydrodynamicselliptic flow hydrodynamics
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elliptic flow and space eccentricityelliptic flow and space eccentricity
ε/=A 2v 2
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QUESTION IIQUESTION II
Is equilibrium state of hot and dense hadronic matter achieved?
What is the conclusion about it from experiment?
The strong indication that YES.
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Some designations
sQGP for strongly-interacting Quark-Gluon Plasma
Commonly accepted:QGP, pQGP,wQGP
for weakly-interacting Quark-Gluon Plasma
Observables and hadronic matter properties
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KEKETT – CQN Scaling – CQN ScalingKEKETT – CQN Scaling – CQN Scaling
Phys. Rev. Lett. 98, 162301 (2007)
Mesons
Baryons
Quark-Like Degrees of Freedom EvidentQuark-Like Degrees of Freedom Evident
Roy A. Lacey, Stony Brook; Quark Matter 09, Knoxville, TN March 30 - April 4, 2009
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K. Aamodt et al.(ALICE Collaboration), PRL 105, 252302 (2010)
Elliptic flow – energy Elliptic flow – energy dependancedependance
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JET Quenching
Modification of Jet property in AA collisions, because of partons propagating in colored matter, which lose energy.
One of the possible observable
Was predicted in a lot of works. Some of them (not all) are:
1
0)(Pd
J.D.Bjorken (1982), Fermilab – PUB – 82 – 059 - THY.M.Gyulassy and M.Palmer, Phys.Lett.,B243,432,1990.X.-N.Wang, M.Gyulassy and M.Palmer, Phys.Rev.,D51,3436,1995.R.Baier et al., Phys.Lett.,B243,432,1997.R.Baier et al., Nucl.Phys.,A661,205,1999
Jet: A localized collection of
hadrons which come from a fragmenting parton
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High pT (> ~2.0 GeV/c) hadrons in NN
h
h
h
abc
dParton distribution functions
Hard-scattering cross-section
Fragmentation Function
h
)Q,x(f 2aaa/A )Q,x(f 2
bbb/B cdabd )Q,z(D 2ddd/h
d,c,b,ahXABd
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h
High pT (> ~2.0 GeV/c) hadrons in AA
A
B
h Hard-scattering cross-section
Fragmentation Function
Parton distribution functions
+Numbers of binary collisionsPartonic Energy
Loss
(...)f b/B(...)f a/A cdabd
)Q,z(D 2d
*dd/h
1
0 d
*d
z
z)(Pd
∑→dcba
hXABd,,,
=σ CollN
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Nuclear modification factor
is what we get divided by what we expect.is what we get divided by what we expect.
NN
collAAAA d
NdR
σ><σ
=/
From naive picture
AAR
Suppression of high-pt hadrons. Qualitatively.
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Nuclear modification factor
NN
collAAAA d
NdR
σ><σ
=/
Normalization on peripheral collisions
pcollAA
ccollAACP )N/d(
)N/d(R
><σ><σ
=
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First data in first RHIC RUN
Jet Quenching ! Great!
But (see the next slide)
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Nuclear modifications to hard scattering
Large Cronineffect at SPSand ISRSuppression at RHIC
Is the suppression due to the medium?(initial or final state effect?)
RAA (pT ) d2N AA /dpTdTAAd
2 NN /dpTd
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Centrality dependance
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2020
Au+Au @ sNN
= 200 GeV d+Au @ sNN
= 200 GeV
preliminary
Au+Au @ sNN
= 200 GeV d+Au @ sNN
= 200 GeV
preliminary
Au+Au @ sNN
= 200 GeV d+Au @ sNN
= 200 GeV
preliminary
Au+Au @ sNN
= 200 GeV d+Au @ sNN
= 200 GeV
preliminary
• Nice picture! Isn’t it?
Again Au+Au and d+Au
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The matter is so opaque that even The matter is so opaque that even
a 20 GeV a 20 GeV 00 is stopped is stopped..
• Suppression is very strong (RAA=0.2!) and flat up to 20 GeV/c• Common suppression for 0 and it is at partonic level• > 15 GeV/fm3; dNg/dy > 1100
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.ALICE Collaboration, Physics Letters B 696 (2011) 30.
JET Quenching at LHC
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ALICE Collaboration, Physics Letters B 696 (2011) 30
JET Quenching at LHC
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The matter is so dense that even heavy quarks are stopped
Even heavy quark (charm) suffers substantial energy loss in the matter
The data provides a strong constraint on the energy loss models.
The data suggest large c-quark-medium cross section; evidence for strongly coupled QGP?(3) q_hat = 14 GeV2/fm
(2) q_hat = 4 GeV2/fm
(1) q_hat = 0 GeV2/fm
(4) dNg / dy = 1000
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If there are any other observables for Jet Quenching?
Correlation of trigger particles 4<pT<6.5 GeV withassociated particles 2<pT<pT,trig
Associated particles
Near side jetTrigger particle
Away side jet
Yes! Back to Back Jets correlation.
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In-plane In-plane
Out-of-plane
Out-of-plane
Back to Back Jets correlation.Back to Back Jets correlation.Dependence from reaction plane.Dependence from reaction plane.
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Jet tomography
20-60%
STAR Preliminry
20-60%
Back-to-back suppression depends on the reaction plane orientation
In-plane
Out-plane
energy loss dependence energy loss dependence on the path length!on the path length!
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The matter is so dense that it The matter is so dense that it modifies the shape of jetsmodifies the shape of jets
• The shapes of jets are modified by the matter.– Mach cone?– Cerenkov?
• Can the properties of the matter be measured from the shape?– Sound velocity– Di-electric
constant• Di-jet tomography is
a powerful tool to probe the matter
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Resonances melting (Debye scrinig)
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One more results from lattice QCD
heavy-quark screening mass
r/)rexp(~)r(
In EM plasma it is well known Debye screening
T/1~r/1 D
/J -- suppression
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The matter is so dense that it melts(?) J/ (and regenerates it ?)
CuCu
200 GeV/c
AuAu
200 GeV/c
dAu
200 GeV/c
AuAuee
200 GeV/c
CuCuee
200 GeV/c
J/’s are clearly suppressed beyond the cold nuclear matter effect
The preliminary data are consistent with the predicted suppression + re-generation at the energy density of RHIC collisions.
Can be tested by v2(J/)?
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The matter is so dense that it melts Y.
QM’11
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direct photons
3333
• T0max ~ 500-600 MeV !?
T0ave ~ 300-400 MeV !?
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SummarySummary
o RHIC has produced a strongly interacting,RHIC has produced a strongly interacting, partonic state of dense matterpartonic state of dense matter
/ 15 3fmGeVBj
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SummarySummary
o The matter is so dense that even heavy quarks are stopped
(3) q_hat = 14 GeV2/fm
(2) q_hat = 4 GeV2/fm
(1) q_hat = 0 GeV2/fm
(4) dNg / dy = 1000
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SummarySummary
o The matter is so strongly coupled that even heavy quarks flow
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SummarySummary
o The matter is so dense that it melts(?) J/ (and regenerates it ?)
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SummarySummary
o The matter modifies jets
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The matter is hot 3939
The matter may melt but regenerate J/’s
Put the results together
The matter is denseThe matter is strongly coupled
The matter modifies jets
> 15 GeV/fm3
dNg/dy > 1100
Tave = 300 - 400 MeV (?)PHENIX preliminary
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Backup slidesBackup slides
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CGC
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CGC
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CGC
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January 6, 2002 RHIC/INT Winter Workshop 2002 45
Modeling the Source• Interaction region
Assembly of classical boson emitting sources in space-time region
• The source S(x,p) is the probability boson with p is emitted from xDetermines single-particle momentum spectrum
E d3N/dp3 = d4x S(x,p)
Determines the HBT two-particle correlation function C(K,q) C(K,q) ~ 1 + | d4x S(x,K) exp(iq·x) | 2/| d4x S(x,K) |2
where K = ½(p1 + p2) = (KT, KL), q = p1 – p2
The LCMS frame is used (KL = 0)
• In the hydrodynamics-based parameterizations: assume something about the source S(x,p)Gaussian particle density distribution
Linear flow (rapidity or velocity) profile
Instantaneous freeze-out at constant proper time (“sharp”)
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CollN(...)/ aAf (...)/ bBf cdabd
1
0 d
*d
z
z)(Pd )Q,z(D 2
d*dd/h∑
dcba ,,,
(...)/ aAf (...)/ bBf cdabd ),(/2dddh QzD∑
dcba ,,,
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Why the collisons of heavy nuclei is interesting?
Let us see on the space – time picture of collision
pre-collision QGP (?) and parton production
hadron production
hadron reinteraction
QCD phase diagram
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The QGP in the early universe
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What kind of transition is predicted by lattice QCD
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Dependence on pseudorapidity of charged hadron
S.S. Adler et al. , Phys. Rev. C 71, 034908 (2005)
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Theoretical explanation
Comparison to model calculations with and without parton energy loss:
Numerical values range from ~ 0.1 GeV / fm (Bjorken, elastic scattering of partons)~several GeV / fm (BDMPS, non-linear interactions of gluons)
Too many approaches.We need additional data!
2.0~Rand,p~d AuAu8
T
2.0~p/p
Estimation from data
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Initial state effects (test experiment d+Au)
Suppression in central Au+Au due to final-state effects
/h
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5555
Binary scaling. Is it work?
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How about suppression for protons?
pcollccollCP )N/dN/()N/dN(R New
Close to nuclear mod. factor, because no suppression for peripheral coll.
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Jets composition as measured by STAR
Kirill Filimonov, QM’04
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[w/ the real suppression]
( pQCD x Ncoll) / background Vogelsang/CTEQ6
[if there were no suppression]
( pQCD x Ncoll) / ( background x Ncoll)
Au+Au 200 GeV/A: 10% most central collisions
[]measured / []background = measured/background
Preliminary
pT (GeV/c)
Binary scaling. Is it work?
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Theoretical explanation
Comparison to model calculations with and without parton energy loss:
Numerical values range from ~ 0.1 GeV / fm (Bjorken, elastic scattering of partons)~several GeV / fm (BDMPS, non-linear interactions of gluons)
Too many approaches.We need additional data!
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If is there space for Color Glass Condensate or only Cronin Effect?
May be. Look at the BRAMS DATA
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Observables and space time structureObservables and space time structure of of Heavy ion collisionsHeavy ion collisions
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Observables and space time structureObservables and space time structure of of Heavy ion collisionsHeavy ion collisions
Production of hard particles: jets heavy quarks direct photonsCalculable with the tools of perturbative QCD
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Observables and space time structureObservables and space time structure of of Heavy ion collisionsHeavy ion collisions
Production of semi-hard particles: gluons, light quarks relatively small momentum: make up for most of the multilplicity
cGeVpT / 21
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6666
Observables and space time structureObservables and space time structure of of Heavy ion collisionsHeavy ion collisions
Thermalizationexperiment suggest a fast thermalization (remember elliptic flow)but this is still not undestood from QCD
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Observables and space time structureObservables and space time structure of of Heavy ion collisionsHeavy ion collisions
Quark gluon plasma
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Observables and space time structureObservables and space time structure of of Heavy ion collisionsHeavy ion collisions
Hot hadron gas
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Particle ratio and sParticle ratio and statistical modelstatistical models
These models reproduce the ratios of particle yields with only two parameters
One assumes that particles are produced by a thermalized system with temperature T and baryon chemical potential
The number of particles of mass m per unit volume is :
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7070
N/ ratio shows baryons enhanced for pT < 5 GeV/c
One more observable. Particle ratios