Transcript PPT

Understanding deconfinement:
new spectroscopy at T>Tc
Edward Shuryak
Department of Physics and Astronomy
State University of New York
Stony Brook NY 11794 USA
Outline
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The ``little bang” at RHIC
=> A strongly coupled QGP
Lattice puzzles
Hadrons above Tc
Bound colored states
AdS/CFT at finite T
RHIC: a view from space
A dedicated collider for
(i) Heavy ion
collisions, AuAu
100+100 GeV/N
(ii) Polarized pp,
250+250 GeV
One of the first RHIC events at STAR detector,
The average
multiplicity at
AuAu 200
GeV/N
Is about 5000
Spectra of various secondaries
from all 4 detectors
Main findings at RHIC
• Particles are produced from matter which seems to be
well equilibrated (by the time it is back in hadronic
phase), N1/N2 =exp(-(M_1-M_2)/T)
• Very robust collective flows were found, indicating very
strongly coupled Quark-Gluon Plasma (sQGP)
• Strong quenching of large pt jets: they do not fly away
freely but are mostly (up to 90%)
absorbed by the matter. The deposited energy seem
to go into another hydrodynamical motion (conical flow)
Reminder
Statistical Model
Works well with just two parameters
p e  ( E μ ) / T
 ( E μ) / T  e 2μ / T
p e
Hadro-chemistry seems to be all done at the critical line
Hydrodynamics is simple and very
predictive <= only the EoS is needed,
provided by the lattice (at finite T)
Local Energy-momentum
conservation:
Conserved number:
Dynamic Phenomena
•Expansion, Flow
•Space-time evolution of
thermodynamic variables
Caveat: Why and when the
equilibration takes place is
a tough question to answer
Elliptic flow at RHIC
Explosion goes in all directions
Radial and especially
Elliptic flow
The red almond-shaped
region is where the dense
matter is. Yellow region
shows “spectators” which
fly by without interaction
The so called “jet
tomography” of the initial
shape of the matter
hydro describes both radial and elliptic flows
(from Phenix) v_2=<cos(2 phi)>
proton
pion
nucl-ex/0410003
Hydro models:
Teaney
(w/ & w/o
RQMD)
Hirano
(3d)
Kolb
Huovinen
(w/& w/o
QGP)
Sonic boom from
quenched jets Casalderrey,ES,Teaney,
hep-ph/0410067; H.Stocker…
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the energy deposited
by jets into liquid-like
strongly coupled QGP
must go into conical
shock waves, similar
to the well known
sonic boom from
supersonic planes.
We solved relativistic
hydrodynamics and
got the flow picture
If there are start and
end points, there are
two spheres and a
cone tangent to both
Distribution of radial velocity
v_r (left) and modulus v (right).
(note tsunami-like features, a positive
and negative parts of the wave)
PHENIX jet pair distribution
Note: it is only
projection of a
cone on phi
Note 2: more
recent data from
STAR find also a
minimum in
<p_t(\phi)> at
180 degr., with
a value
Consistent with
background
Collective flows
=>collisional regime
=> hydrodynamics
The main assumption:
l << L
(the micro scale) << (the macro scale)
(the mean free path) << (system size)
(relaxation time) << (evolution duration)
•In the zeroth order in l/L it is ideal hydro with a local stress
tensor.
I
•Viscosity appears as a first order correction l/L, it is inversely
proportional to the cross section and thus is (the oldest)
strong coupling expansion tool
Viscosity of QGP
QGP at RHIC seem to be the most ideal
fluid known, its
viscosity/(entropy density) =.1 -.2
water would not flow if only a drop with 1000 molecules be made
1st order correction to dist. fn.:
:Sound attenuation length
Velocity gradients
D.Teaney(’03)
What is needed to reproduce the
magnitude of v2?
Huge cross sections!!
Charm transport (the diffusion coeff.)
Moore&Teaney, hep-ph/0412346
Mc/T=6-7 more collision needed for equilibration
How to get 20 times pQCD s?
(Zahed and ES,2003)
• Quark-antiquark bound states don’t all melt at
Tc (charmonium from lattice known prior to
that…)
• Many more colored channels
• all q,g have strong rescattering qqbar  meson
Resonance enhancements
Huge cross section due to resonance enhancement
causes elliptic flow of trapped Li atoms
Resonance enhancement near zero binding
lines provides large cross section
(ES+Zahed,03)
Well, it was shown to work for strongly coupled atoms
Scattering amplitudes
for quasiparticles
M. Mannarelli. and R. Rapp hep-ph/05050080
The coolest thing on Earth, T=10 nK or
10^(-12) eV can actually produce a
Micro-Bang ! (O’Hara et al,
Duke )
Elliptic flow with ultracold trapped
Li6 atoms, a=> infinity regime
The system is extremely dilute, but
can be put into a hydro regime, with
an elliptic flow, if it is specially tuned
into a strong coupling regime via the
so called Feshbach resonance
Similar mechanism was proposed
(Zahed and myself) for QGP, in which
a pair of quasiparticles is in
resonance with their bound state at
the “zero binding lines”
The new spectroscopy at
T>Tc
The QCD Phase Diagram
T
The lines marked RHIC and SPS show the paths matter makes while
cooling, in Brookhaven (USA) and CERN (Switzerland)
Theory prediction (numerical calculation,
lattice QCD, Karsch et al) the pressure as a
function of T (normalized to that for free
quarks and gluons)
Chemical potential mu
Is it weakly coupled?
lattice puzzles
• it was recently found fom correlators
(Asakawa-Hatsuda,Bielefeld) that
J/,c dissolves in QGP only at
T>(2-3)T_c.Why?
Because the coupling is very strong!
• How can pressure be high at
T=(1.5-2)T_c
while q,g quasiparticles are quite
heavy?
Because there also numerous
bound states
``free energies” for static quarks
(Karsch et al)
•Upper figure is
normalized at small
distances: one can
see that there is
large ``effective
mass” for a static
quark at T=Tc.
•Both are not yet
the potentials!
•The lower figure
shows the effective
coupling constant
Fitting F to
screened Coulomb
• Fit from Bielefld group
hep-lat/0406036
•Note that the Debye
radius corresponds to
``normal” (enhanced by factor 2)
coupling, while the overall strength
of the potential is much larger
•It becomes still larger if V is used
instead of F, see later
The potentials should have the entropy
term subtracted,
which makes potentials deeper still
this is how potential I got look like for T = 1; 1.2; 1.4; 2; 4; 6; 10Tc,
from right to left, from ES,Zahed hep-ph/0403127
Here is the binding and |psi(0)|^2
(J/psi puzzle resolved!)
E/2M
Vs T/Tc
If a Coulomb coupling is too strong,
falling onto the center may occur:
but it is impossible to get a binding
comparable to the mass
But we need massless pion/sigma at T=>Tc !
• Brown,Lee,Rho,ES hepph/0312175 : near-local
interaction induced by the
``instanton molecules”
(also called ``hard glue” or
``epoxy”, as they survive
at T>Tc
• Their contribution is »
|(0)|2 which is calculated
from strong Coulomb
problem
Solving for binary bound states
ES+I.Zahed, hep-ph/0403127
• In QGP there is no confinement =>
• Hundreds of colored channels must
have bound states as well!
The pressure puzzle is resolved!
Masses, potentials and EoS from lattice are
mutually consistent
M/Tc vc T/Tc and p/pSB vs T/Tc
Can we verify existence of bound
states at T>Tc experimentally?
Dileptons from sQGP:
The widths are being calculated…
But see, one can see peaks Karsch-Laerman, T=1.5 and 3 Tc
on the lattice
Asakawa-Hatsuda
T=1.4Tc
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A gift by the string theorists,
the AdS/CFT correspondence,
should help us understand sQGP
QCD vs CFT:
let us start with EoS
(The famous .8 explained!)
Strongly coupled CFT plasma is a
very good liquid!
• AdS/CFT calculation (D.Son et al 2003)
of the correlator <Tmunu(x) Tmunu(0)>
Via graviton propagator
=>
 / s  hbar / 4
viscosity/ (entropy density)
=> It is about as small as observed at RHIC!
Bound states in AdS/CFT
(ES and Zahed, PRD 2004)
• The quasiparticles are heavy
M_q =O(sqrt(lambda) T) >> T, exp(-M_q/T)<<1
• But there should be light binary bound states
with the mass O(M_q/sqrt(lambda))=O(T)
• Using Dirac/KG eqns with supercritical coupling
one gets states falling on the center if
l<sqrt(lambda)
• But recent work on ``quarkonia” with D3D7
brane construction (e.g.M.Strassler et al 05)
found that the s-wave states survive, with exactly
the right mass O(M_q/sqrt(lambda))
A complete ``gravity dual” for RHIC
from 10-d GR? (ES,Sin,Zahed, in progress)
Black Holes + Howking rad. Is used
to mimic the finite T
How black hole is produced can be
calculated from GR (tHooft …
Nastase)
Entropy production => black hole
formation, falling into it is viscosity
Moving brane => hydro expansion
Conclusions
• QGP as a “matter” in
the usual sense, not a
bunch of particles, has
been produced at
SPS/RHIC
• It shows very robust
collective flows. The
EoS is as expected: but
QGP seems to be the
most ideal fluid known
eta/hbar s=.1-.2 <<1
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All of this hints that
QGP is in a strong
coupling regime, with
new spectroscopy of
colored states
• Interesting analogies
with other strongly
coupled systems
• ``quantum gases”
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AdS/CFT
Is such a sonic boom already
observed?
Mean Cs=.33 time average over 3 stages=>
 +/-1.23=1.91,4.37
M.Miller, QM04
away <pT> dependence on angle
(STAR,preliminary)
Preliminary
<pT> (phi) has a dip structure in central AA.
Mach shock wave?