John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Heavy Ions - Phenomenology and Status
LHC
• Introduction to Rel. Heavy Ion Physics• The Relativistic Heavy Ion Collider (RHIC)• Creating Hot Bulk QCD Matter• Using Hard Scattering to Probe the Matter• Conclusions & Expectations
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Early Universe
National Geographic(1994)
&Michael Turner
quark-hadronphase transition2 x 1012 Kelvin
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Lattice QCD at Finite Temperature
F. Karsch, et al.Nucl. Phys. B605 (2001) 579
mu,d= ms
mu = md
ms mu,d
Action density in 3 quark system in full QCDH. Ichie et al., hep-lat/0212036
G. Schierholz et al., Confinement 2003
Heavy quarks suppressed exp(-mc,b,t/T)TC ~ 175 8 MeV C ~ 0.3 - 1 GeV/fm3
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Hot Bulk QCD Matter (QGP)• Standard Model Lattice Gauge Calculations predict
Deconfinement phase transition at high T in QCD
• Cosmology Quark-hadron phase transition in early Universe• Astrophysics Cores of dense stars
• Establish bulk properties of QCD at high T and density
• Can we make it in the lab?
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Relativistic Heavy Ion Collider
STARPHENIX
PHOBOS BRAHMS
RHIC
Design Performance Au + Au p + pMax snn 200 GeV 500 GeVL [cm-2 s -1 ] 2 x 1026 1.4 x 1031
Interaction rates 1.4 x 103 s -1 3 x 105 s -1
Two Concentric Superconducting Rings
Ions: A = 1 ~ 200, pp, pA, AA, AB
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Relativistic Heavy Ion Collider and Experiments
STARSTAR
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Space-time Evolution of RHIC Collisions
e
space
time jet
Hard Scattering + Thermalization (< 1 fm/c)
AuAu
Exp
ansio
n
Hadronization
p K
Freeze-out(~ 10 fm/c)
QGP (~ few fm/c)
e
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
What Can We Learn from Hadrons at RHIC?• Can we learn about Hot Nuclear Matter?
– Equilibration? Thermodynamic properties?– Equation of State?– How to determine its properties?
• Hadron Spectrum
Soft Physics reflect bulk properties (pT < 2 GeV/c( )99% o f
hadrons)
Hard Scattering & Heavy Quarks probe the medium
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
What Have We Learned at RHIC So Far?
Large energy densities dn/ddET/d GeV/fm3
x nuclear densityCollective phenomena: Large elliptic flow Extreme early pressure gradients & energy densities
Hydrodynamic & requires quark-gluon equation of state!
Global observations: Large produced particle multiplicities dnch/d |=0 = 670, Ntotal ~ 7500 15,000 q +q in final state, > 92% are produced quarks
Quark coalescence / recombination & flow constituent quark degrees of freedom
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Elliptic Flow Early Pressure in System
x
z
y
Initial Ellipticity(coord. space)
ReactionPlane (xz)
Sufficient interactions early (~ 1 fm/c) in system to respond to early pressure? before self-quench (insufficient interactions)?
System able to convert original spatial ellipticity into momentum anisotropy?
Sensitive to early dynamics of initial system
p
p
Azimuthal anisotropy(momentum space)
?
) FlowElliptic
2cos2 FlowDirected
cos2 Isotropic
1 ( 21
21
2
3
3
RPRPtt
vvdydpp
dpd
dE
x
y
pp
atan
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Large Elliptic Flow Observed• Azimuthal asymmetry of charged
particles: dn/d ~ 1 + 2 v2(pT) cos (2) + ...
x
z
y
Particle mass dependence of v2
requires
• Early thermalization
• Ideal hydrodynamics • Quark-gluon Equation of State
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Quark Recombination and Elliptic FlowComplicated v2(pT) flow pattern is observed for identified hadrons
d2n/dpTd ~ 1 + 2 v2(pT) cos (2 )If the flow is established at the quark level, it is predicted to be simple when pT → pT / n , v2 → v2 / n , n = (2, 3 quarks) for (meson, baryon)
15000 quarks flow collectively
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
More Data on v2 and Quark Recombination
• e.g. take strange particle v2• v2 of all hadrons obey quark recombination systematics!
Au+Au sNN=200 GeVSTAR Preliminary
MinBias 0-80%
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
What Have We Learned at RHIC So Far?
Large energy densities dn/ddET/d GeV/fm3
x nuclear densityCollective phenomena: Large elliptic flow Extreme early pressure gradients & gluon densities
quark-gluon equation of state!
Global observations: Large produced particle multiplicities dnch/d |=0 = 670, Ntotal ~ 7500 15,000 quarks in final state, > 92% are produced quarks
“Chemical” equilibration (particle yields & ratios): Particles yields represent equilibrium abundances
universal hadronization temperature
Quark coalescence / recombination & flow constituent quark degrees of freedom
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
• Chemically and thermally equilibrated fireball at one temperature T and one ( baryon) chemical potential : – One ratio (e.g., p / p ) determines / T :– Second ratio (e.g., K / ) provides T
• Then all hadronic yields and ratios determined:
Particle Ratios Chemical Equilibrium Temperature
pdedn E 3/)(~ Tμ
TμTμ
Tμ/2
/)(
/)(
eee
pp
E
E
Ratios equilibrium values
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Soft Sector (Bulk Dynamics) -What We Have Learned at RHIC!
Large energy densities dn/ddET/d GeV/fm3
x nuclear densityCollective phenomena: Large elliptic flow Extreme early pressure gradients & gluon densities
quark-gluon equation of state!
Global observations: Large produced particle multiplicities dnch/d |=0 = 670, Ntotal ~ 7500 15,000 quarks in final state, > 92% are produced quarks
“Chemical” equilibration (particle yields & ratios): Particles yields represent equilibrium abundances
universal hadronization temperature
Quark coalescence / recombination & flow constituent quark degrees of freedom
Small net baryon density K+/K-,B/B ratios) B ~ 25 - 40 MeV Chemical Freezeout Conditions T = 177 MeV, B = 29 MeV T ~ Tcritical (QCD)
“Thermal” equilibration (particle spectra) : Thermal freezeout + large transverse flowTFO = 100-110 MeV, T = 0.5 – 0.6c
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Hard Scattering to Probe the Hot Bulk QCD Medium
hadrons
leading particle
hadronsleading particle
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Inclusive Hadron pt-spectra: s = 200 GeV AuAu
power law: pp = d2N/dpt
2 = A (p0+pt)-n
Preliminary
STAR
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Hadron Spectra: Comparison of AA to NN
Nuclear Modification Factor RAA:AA = Nucleus-NucleusNN = Nucleon-Nucleon
ddpdT
ddpNdpRT
NNAA
TAA
TAA //)( 2
2
Nuclear overlap integral:# binary NN collisions / inelastic NN cross section
NN cross section
AA cross section
AA
(pQCD)
Parton energy loss R < 1 at large Pt
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Suppression of High Transverse Momentum Hadrons at RHIC• Large transverse momentum hadrons are suppressed in central
collisions at RHIC
√snn = 17.3 GeV
√snn = 63 GeV
√snn = 130 GeV
by factor ~ 4 - 5 in central collisionsat RHIC
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Centrality Dependence of Suppression at RHICAu+Au130 GeV
Phys. Rev. Lett. 89, 202301 (2002)STAR
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Is Origin of Suppression Initial or Final State?
Final stateparton energy
loss?
A + A collisions in medium:
gluon saturation?
nuclear effects in initial state
Initial state
no partonenergy loss
nuclear effects in initial state
gluon saturation?p,d + A collisions -
no medium
Distinguish effects -initial statefinal state
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Final State Suppression / Initial State Enhancement!• The hadron spectra at RHIC from p-p, Au-Au
and d-Au collisions establish existence of a new final-state effect - early parton energy loss – from strongly interacting, dense matter in central Au-Au collisions
Au + Au Experiment d + Au Control Experiment
Preliminary DataFinal Data
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Extreme Energy Densities! – Au-Au suppression
(I. Vitev and M. Gyulassy, hep-ph/0208108)– d-Au enhancement (I. Vitev, nucl-th/0302002 )
understood in an approach that combines multiple scattering with absorption in a dense partonic medium
high pT probesrequire
dNg/dy ~ 1100
> 100 0 Au-Au
d-Au
Au + Au
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Hard Scattering (Jets & Leading Particles)as a Probe of Dense Matter
Jet event in eecollision STAR p + p jet event
Can we see jets in high energy Au+Au?
STAR Au+Au (jet?) event
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Au+Au Leading Particle (Jet) Azimuthal Correlations
Assume:Au+Au event with high pT particle is a superposition of
p+p event w. high pT particle + AuAu event w. elliptic flow
– v2 from reaction plane analysis
– A from fit in non-jet region (0.75 < || < 2.24)
C2(Au Au) C2(p p) A * (1 2v22 cos(2))
Peripheral Au + Au
Away-side jet
STAR 200 GeV/cperipheral & central Au+Au
p+p minimum bias4<pT(trig)<6 GeV/c
2<pT(assoc.)<pT(trig)Central Au + Au
disappears
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Path Length Dependence of “Di-jet” Topologies
y
x
pTtrigger=4-6 GeV/c, 2<pT
associated<pTtrigger, ||<1
in-plane
Out-of-plane
Back-to-back suppression out-of-plane stronger than in-plane
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Hammering the Nail in the Coffin
Pedestal&flow subtracted
no jet quenching!
d + Au “di-jet” correlations similar to p + p
Au + Au away-side correlation quenched!
Quenching of Away-side “jet” is final state effect
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Hard Scattering Comments
High Pt hadrons suppressed in central Au + Au enhanced in d + AuBack-to-back Jets Di-jets in p + p, d + Au
(all centralities) Away-side jets quenched
in central Au + Auemission from surfacestrongly interacting medium
x
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Summary - What Have We Learned at RHIC So Far?
Quark coalescence /flow constituent quark degrees
of freedom
Extreme initial densities – 5 GeV/fm3
~ 30 - 100 x nuclear density
> 15,000 q +q in final state
Equilibrium abundances – Universal hadronization T ~ Tcrit
Rapid u, d, s equilibration near Tcrit
parton E loss – large gluon densities opaque!
Ideal hydro - Early thermalization & quark-gluon EOS
Pedestal&flow subtracted
parton E loss – large gluon densities opaque!
Indicates strongly interacting, bulk QCD-matter formed in RHIC collisions
PRL 91 072305 (2003)Initial state gluon saturation (color glass condensate?) - forward rapidities low-x d+Au is suppressed
John Harris (Yale) LHC Conference, Vienna, Austria, 15 July 2004
Still to do!
RAA d 2N AA dydpT
d 2N pp dydpT NcollAA
Deconfined QGP?cc, bb suppression & melting sequence Strangeness enhancement?
Thermalized? Open charm, beauty, multiply-strange baryon production & flow
Establish properties of the QCD mediumProbe parton E-loss with higher pT triggers, jets, -jetFlavor dependence of suppression & propagationLight vector mesons (mass and width modifications)
Direct Photon Radiation?New phenomena…….LHC! RHIC II!
“the adventure continues!”
John Harris (Yale) Hadron Collider Conference, East Lansing MI, 6/14/04
Still the beginning