Heavy Ion Theory Review Raju Venugopalan Brookhaven National Laboratory LHC week in Split, October...
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![Page 1: Heavy Ion Theory Review Raju Venugopalan Brookhaven National Laboratory LHC week in Split, October 1-6, 2012.](https://reader030.fdocuments.in/reader030/viewer/2022032723/56649f565503460f94c7acaa/html5/thumbnails/1.jpg)
Heavy Ion Theory Review
Raju VenugopalanBrookhaven National Laboratory
LHC week in Split, October 1-6, 2012
![Page 2: Heavy Ion Theory Review Raju Venugopalan Brookhaven National Laboratory LHC week in Split, October 1-6, 2012.](https://reader030.fdocuments.in/reader030/viewer/2022032723/56649f565503460f94c7acaa/html5/thumbnails/2.jpg)
Heavy Ion Theory (Selective) Review
Raju VenugopalanBrookhaven National Laboratory
LHC week in Split, October 1-6, 2012
![Page 3: Heavy Ion Theory Review Raju Venugopalan Brookhaven National Laboratory LHC week in Split, October 1-6, 2012.](https://reader030.fdocuments.in/reader030/viewer/2022032723/56649f565503460f94c7acaa/html5/thumbnails/3.jpg)
Some key questions in heavy ion physics
How is entropy produced and what is the nature of the matter produced ?
How does strongly correlated matter evolve ?
How do hard probes (jets, Onia,…) interact with the matter ?
What can we learn about how emergent features (topological, chiral) of QCD with varying T, μB and B ?
![Page 4: Heavy Ion Theory Review Raju Venugopalan Brookhaven National Laboratory LHC week in Split, October 1-6, 2012.](https://reader030.fdocuments.in/reader030/viewer/2022032723/56649f565503460f94c7acaa/html5/thumbnails/4.jpg)
Some key questions in heavy ion physics
How is entropy produced and what is the nature of the matter produced ?
How does strongly correlated matter evolve ?
How do hard probes (jets, Onia,…) interact with the matter ?
What can we learn about how emergent features (topological, chiral) of QCD with varying T, μB and B ?
Close analogies to key issues in strongly correlated electron systems, Bose-Einstein condensates, early universe cosmology (inflation and hot era), plasma physics, chaotic dynamical systems, classical and quantum gravity
![Page 5: Heavy Ion Theory Review Raju Venugopalan Brookhaven National Laboratory LHC week in Split, October 1-6, 2012.](https://reader030.fdocuments.in/reader030/viewer/2022032723/56649f565503460f94c7acaa/html5/thumbnails/5.jpg)
Multi-particle production: saturated wave-functions
Incoming nuclei are Color Glass Condensates: Highly occupied gluon states with maximal occupancy allowed in QCD
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Multi-particle production: saturated wave-functions
Energy evolution of multi-gluon correlators (on sat. scale ~ 1/QS ) test fundamental features of QCD in deeply non-linear regime
Dumitru,Jalilian-Marian,Lappi,Schenke,RV, PLB706 (2011)219
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Gluon saturation and CGC: Strong hints
i) Good agreement of saturation models with combined HERA data for x < 0.01
ii) Hadron correlations in deuteron-gold collisions at RHIC
iii) Bulk features of LHC pp data
iv) CMS “ridge” – di-hadron correlations in high multiplicity p+p
Upcoming p+Pb at 5 TeV: possibly stringent tests from multiple final states
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Gluon saturation and CGC: Strong hints
p+pHERA e+p cross-sections
PHENIX, PRL107, 172301 (2011)
d-Au
di-h
adro
n to
p+p
ratio
Theory: Albacete et al. 1203.1043 Theory:Tribedy, RV, 1112.2445
Theory: Dusling, RV, 1201.2658
Theory: Stasto,Xiao,Yuan, 1109.1817
CMS p+p ridge
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Gluon saturation and CGC: p+Pb constraintsAlbacete,Dumitru,Fujii,Nara,1209.2001
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The GlasmaGlasma (\Glaahs-maa\): Noun: non-equilibrium matter between CGC and QGP
Solutions of Yang-Mills equations produce (nearly) boost invariant gluon field configurations: “Glasma flux tubes”
Lumpy gluon fields color screened over transverse distances ~ 1/QS - Convolution of NBD multiplicity distributions.
Glue configurations very unstable to quantum fluctuations & grow exponentially -- important mechanism for early isotropization
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Proof of concept: isotropization of longitudinally expanding fields in scalar Φ4
Dusling,Epelbaum,Gelis,RV, arXiv:1206.3336
(arb. lattice units)
Decoherence EOS Isotropization
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Proof of concept: isotropization of longitudinally expanding fields in scalar Φ4
Dusling,Epelbaum,Gelis,RV, arXiv:1206.3336
(arb. lattice units)
Quantum fluctuations generate an anomalously low viscosity
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Hydrodynamics from quantum fields: τ ~ 1/QS
1/αS
pΛS=Λ=QS
τ >> 1/QS
f(p)
pΛS Λ
1/αS
Thermal on long time scales τ ≈(1/αS)2 1/QS : Λ =T, m2 = Λ ΛS (electric screening), ΛS = αST (magnetic screening)
f(p)
Isotropization (and hydrodynamics) can take place on very short time scales ~ 1/QS
Interplay of isotropization vs thermalization: extract from photon spectra + flow, di-leptons for pT < M, long range rapidity corr. ?
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The first fermi: a master formula
Gauge invariant Gaussian spectrum of quantum fluctuations
From solutions of B-JIMWLK
3+1-D solutions of Yang-Mills equations
Also correlators of Tμν
Expression computed recently-numerical evaluation in progress
Dusling,Epelbaum,Gelis,RV
This is what needs to be matched to viscous hydrodynamics, event-by-event
All modeling of initial conditions for heavy ion collisions includes various degrees of over simplification relative to this “master” formula
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2+1-D Yang-Mills2+1-D Yang-Mills + 2+1-D Viscous hydro
IP-Glasma model: match event-by-event Yang-Mills to viscous hydro
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Heavy Ion phenomenology: IP-Glasma modelSchenke,Tribedy,RV: PRL108 (2012), 252301; arXiv:1206.6805I) Multiplicity distributions
+
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IP-Glasma model
Gale,Jeon,Schenke,Tribedy,RV, 1209.6330
II) Harmonic flow moments (2+1-D CYM + viscous hydro a la MUSIC)
+-
MUSIC:Schenke,Jeon,Gale (2011)
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IP-Glasma modelTemperature dependent η/s Niemi et al PRL106 (2011)
RHIC and LHC have ~ 70% different η/s
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Heavy Ion phenomenology: IP-Glasma modelGale,Jeon,Schenke,Tribedy,RV, 1209.6330
+
Event-by-event flow distributions
vn distributions track eccentricities εn
spatial fluctuations
efficiency => perfect fluidity
momentum anisotropies
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ISMD Hiroshima, Japan: September, 2011
P
WMAPHIC-ALICE
Credit: NASA
The Universe HIC
QGP phasequark and gluon degrees of freedom
hadronization
kineticfreeze-out
lumpy initial energy density
distributions and correlations of
produced particles
Flow moments: analogy with the Early Universe
Δφ
Δρ/√ρref
Mishra et al; Mocsy- Sorensen
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Jet probes of strongly correlated QGPJ. Milhano, QM12 talk
Radiative energy loss Broadening due to multiple Scattering & El. Scat. Energy loss Modification of color correlations
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Jet probes of strongly correlated QGPJ. Milhano, QM12 talk
is a measure of the transport properties of the medium
In kinetic theory, Independent measurements of l.h.s & r.h.s test simple quasi-particle pictures
Majumder,Muller,Wang (2007)
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Jet probes of strongly correlated QGP
Remarkable pattern of suppression up to 300 GeV!
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Jet probes of strongly correlated QGP
pQCD
AdS/CFTTwo extremes for Jet-Medium interactions
At the LHC, jets retain shape but significant radiation outside cone
Fragmentation functions and differential jet shapes
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Jet probes of strongly correlated QGP
Milhano
Simple pQCD model based on soft gluons kicked out of shower by mult. scatt. consistent with di-jet data on x= pt1/pt2 and z
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Jet probes of strongly correlated QGP
Problem: medum modification of parton shower
Recent progress: in medium splitting has probabilistic interpretation Mehtar-Tani, Salgado,Tywoniuk, 1205. 5739Casalderrey-Solana,Iancu,1105.1760Blaizot,Dominguez,Iancu,Mehtar-Tani,1209.4585
Implement in MCs: HIJING,Q-PYTHIA,Q-HERWIG,JEWELL,YaJEM
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Quarkonium probes of strongly correlated QGP
(1S)
(2S)
Rapp et al., QM2012
Onium regeneration models give good description of LHC data
Important ingredient: Im V(r) -- recent progress in NRQCD models -- AdS & Latt.models show similar trends
See, for eg., T. Hatsuda, QM12 plenary
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Topology of excited vacuum: Chiral Magnetic Effect
Sphaleron transitions in external B field can lead to induced charge separation – Chiral Magnetic Effect
N
C
S
=
-2
-
1
0
1
2
Kharzeev,McLerran,Warringa, NPA (2008)
outin
RP
BaaBvv
,1,1
)cos(
Conventional explanations (charge conservation + v2) exist…Pratt,Schlichting
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Topology of excited vacuum: Chiral Magnetic Effect
N
C
S
=
-2
-
1
0
1
2
70-80%
0-1% spectator neutrons
Effect disappears with B field…but v2 is 2.5%
Very preliminary, but if confirmed would be spectacular…
Corollary: isotropization may also proceed through sphaleron decayShuryakRV
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QCD at finite μB
Chiral transition μB=0: Tc=154±9 / 157±6 MeV (hot QCD/ Wuppertal-Budapest)
Some chiral models predict negative Kurtosis as signature of Critical End PointAlso negative χ6 / χ2
Exciting potential of RHIC high statistics BES !
![Page 31: Heavy Ion Theory Review Raju Venugopalan Brookhaven National Laboratory LHC week in Split, October 1-6, 2012.](https://reader030.fdocuments.in/reader030/viewer/2022032723/56649f565503460f94c7acaa/html5/thumbnails/31.jpg)
Recap: key questions in heavy ion physics How is entropy produced and what is the nature of the
matter produced ?
How does strongly correlated matter evolve ?
How do hard probes (jets, Onia,…) interact with the matter ?
What can we learn about how emergent features (topological, chiral) of QCD with varying T, μB and B ?
We are making empirical progress on all these fronts, but… there’s a long way to go before we can claim to understand the complex collective dynamics of the only accessible non-Abelian Field Theory
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In the meanwhile,
Happy 75 birthday, Guy !!