Mirko Planinić

LHC Days in Split1-6 October 2012

University of Zagreb

Overview of RHIC results Overview of RHIC results

We will never see the whole We will never see the whole bodybody

Mirko Planinić

LHC Days in Split 2012

Jet quenching

High pT suppression

Energy density>Ec

Constituent quark scaling

Elliptic flow

We will never see the whole We will never see the whole bodybody

Critical point ?

Mirko Planinić

LHC Days in Split 2012

to study structure of an atom…

“neutral” proton

…separate constituents

Imagine our understanding of atoms or QED if we could not isolate charged objects!!

nucleus

electron

quark

“white” proton(confined quarks)

“white” π0

(confined quarks)

Confinement: fundamental & crucial (but not understood!) feature of QCD- colored objects (quarks) have ∞ energy in normal vacuum

neutral atom

Generating a deconfined stateGenerating a deconfined state

Nuclear Matter(confined)

Hadronic Matter(confined)

Quark Gluon Plasmadeconfined

Present understanding of Quantum Chromodynamics (QCD)• heating• compression deconfined color matter

Expectations from Lattice QCDExpectations from Lattice QCD

ε/T4 ~ # degrees of freedom

confined:few d.o.f.

deconfined:many d.o.f.

Natural language: thermodynamicsPartonic Condensed Matter

Phase diagram of nuclear Phase diagram of nuclear mattermatter

Phase diagram of water

Pre

ssur

e/at

m

Temperature

Navigating the phase diagram

Chemical freeze-out: when the yields of particles stop changing•yields determined by temperature and chemical potential•equilibrium is assumed!

Kinetic freeze-out: when momentum distributions stop changing•occurs after chemical freeze-out, after cooling and expansion•spectra determined by temperature and collective motion

Freeze-out: that stage of the collision when something stops evolving•the nature of heavy ion physics: we only see the system after freezeout!•in reality, not a moment in time, nor even a sharp hypersurface

Freeze-out

1 km

World’s (second) largest operational heavy-ion colliderWorld’s (second) largest operational heavy-ion colliderWorld’s largest polarized proton colliderWorld’s largest polarized proton collider

RHICRHIC BRAHMSBRAHMSPHOBOSPHOBOS

PHENIXPHENIXSTARSTAR

AGSAGS

TANDEMSTANDEMS

RRelativistic elativistic HHeavy eavy IIon on CColliderolliderBrookhaven National Laboratory (BNL), Upton, NYBrookhaven National Laboratory (BNL), Upton, NY

Animation M. Lisa

9

Recorded DatasetsRecorded Datasets

10

04/21/2311

STAR Detectors

Full 2π coverage Excellent particle identification capabilities (Using TOF and TPC)

dE/dx clean PID: pion/kaon: pT ~ 0.6 GeV/c and proton pT~ 1.0 GeV/cWith TOF : pion/kaon: pT ~ 1.6 GeV/c and proton pT~ 3.0 GeV/c

p

K

Measurement by PHENIX Measurement by PHENIX DetectorsDetectors

12

0 5-5

ZDC/SMD

dN/d

RXN in: 1.5<||<2.8 & out: 1.0<||<1.5

MPC: 3.1<||<3.7

BBC: 3.0<||<3.9

CNT: ||<0.35✰ PID by EMC&TOF

➫ charged π/K are selected

✰ Ψn by forward detector RXN

EMCTOF

Stages of the collision ?Stages of the collision ?

•We detect only signals from the last stage.•In order to be sure that we have QGP we must understand all stages of collision (signatures).

Animation by Jeffery Mitchell (B N L).

initial state

pre-equilibrium

QGP andhydrodynamic expansion

hadronization

hadronic phaseand freeze-out

Rat

io o

f go

ld-

gold

to

pro

ton

-p

roto

n

Peripheral Central Mid-Central

We “lose” high momentum (speed) particles for Central Collisions

Comparing High Momentum Comparing High Momentum particlesparticles

High pHigh pTT suppression suppression

STARSTAR2

2

/

/AB T

ABAB NN T

dN d d pR

T d d d p

/ ppAB bin inelasticT N

J. Adams et al, Phys. Rev. Lett. 91 (2003) 072304

Binary coll. scaling

p+p reference

♦ Central Au+Au collisions: factor ~4-5 suppression. ♦ pT >5 GeV/c: suppression ~ independent of pT.♦ pQCD describes data only when energy loss included.

RAA << 1; RdAu > 1 Confirms final state effects present

Mirko Planinić

LHC Days in Split 2012

Photons - unsuppressedHadrons - suppressed

Sur

viva

l Pro

babi

lity

Direct

0,

Confirming the probeConfirming the probe

We have an understood and calibrated probeMirko Planinić

LHC Days in Split 2012

Beam Energy ScanBeam Energy Scan

17

0) Turn-off of sQGP signatures

1) Search for the signals of phase boundary 2) Search for the QCD critical point

BES Phase-I

Detector performance generally improves at lower energies. Geometric acceptance remains the same, track density gets lower.Triggering required effort, but was a solvable problem.

Central Au+Au at 7.7 GeV in STAR TPCCentral Au+Au at 7.7 GeV in STAR TPC

BES Data TakingBES Data Taking

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RRCPCP Suppression of Charged Suppression of Charged Hadrons …Hadrons …

PRL 91, 172302 (2003)

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… … and its Disappearanceand its Disappearance

RCP ≥ 1 at √sNN ≤ 27 GeV - Cronin effect?

PRL 91, 172302 (2003)

20

STAR Preliminary

RRcp cp : Identified Particles: Identified Particles

RCP (K0s) < 1 @ √sNN > 19.6 GeV

RCP > 1 @ √sNN ≤ 11.5 GeV ForFor ppTT > 2 GeV/c: > 2 GeV/c:

• Baryon-meson splitting reduces and disappears with decreasing energy

21

Particle emission patternsParticle emission patterns

Peripheral Collisions: Overlap “hot spot” looks like an almond.

If they do – can learn more about timescales of the “cooling” process and help us distinguish between liquid and gas behavior

Do the particle emission patterns reflect this initial shape?

Reaction plane

x

z

y

Mirko Planinić

LHC Days in Split 2012

QuarkNet 2006

b (reaction plane)

View along beamline

Emission patterns follow the shape of the overlap region.

Mirko Planinić

LHC Days in Split 2012

Fourier analysis of emission Fourier analysis of emission patterns.patterns.

)(cos21)( Rn

R

nvd

dN

Extract n=2, elliptic flow

Find significant values of v2 for peripheral collisions. Behaving like a liquid (collectively)

Elliptic flow observable is sensitive to early evolution of systemLarge v2 is an indication of early thermalization

Energy Dependence of vEnergy Dependence of v22

• The rate of increase with collision energy is slower from 7.7 to 39 The rate of increase with collision energy is slower from 7.7 to 39 GeV compared to that between 3 to 7.7 GeVGeV compared to that between 3 to 7.7 GeV

ALICE: Phys. Rev. Lett. 105, 252302 (2010)PHENIX: Phys. Rev.Lett. 98, 162301 (2007). PHOBOS: Phys. Rev.Lett. 98, 242302 (2007). CERES: Nucl. Phys. A 698, 253c (2002).E877: Nucl. Phys. A 638, 3c(1998). E895: Phys. Rev. Lett. 83, 1295 (1999). STAR 130 Gev: Phys. Rev. C 66,034904 (2002).STAR 200 GeV: Phys. Rev. C 72,014904 (2005).

STAR Preliminary

STAR, ALICE: v2 resultsCentrality: 20-30%

25

vv22(p(pTT): First Result): First Result

STAR: Nucl.Phys. A862-863(2011)125STAR: Nucl.Phys. A862-863(2011)125

v2 (7.7 GeV) < v2 (11.5 GeV) < v2 (39 GeV)

v2 (39 GeV) ≈ v2 (62.4 GeV) ≈ v2 (200 GeV) ≈ v2 (2.76 TeV)

⇒The same Liquid QGP (aka sQGP) from 39GeV to 2.76TeVThe same Liquid QGP (aka sQGP) from 39GeV to 2.76TeV26

STAR BES Program STAR BES Program SummarySummary

27

206 5851120 420

2.557.719.639

775

√sNN (GeV)

B (MeV)

QG

P p

rope

rtie

s

BE

S p

hase

-I

Tes

t Run

Fix

ed T

arge

t

BE

S p

hase

-II

Large range of B in the phase diagram !!!

Explore QCD

Diagram

Summary – BESSummary – BESSTAR results from BES program covering large STAR results from BES program covering large BB

range provide important constraint on QCD phase range provide important constraint on QCD phase diagram. diagram.

Phase boundary effects show uPhase boundary effects show up p Several key sQGP signatures NOT seen at low energiesSeveral key sQGP signatures NOT seen at low energiesHadronic interactions become more important in the Hadronic interactions become more important in the

system created at low collision energiessystem created at low collision energiesBES-II with significantly improved statistics focusing on BES-II with significantly improved statistics focusing on

beam energies beam energies <= 20 GeV<= 20 GeV

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Outlook

29

2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

BES-I

HFT/MTD: Heavy Flavor / Dileptons

BES-II (√sNN ≤ 20GeV)

pA/eA program

Precision measurements on HF and dileptons:Quantify the sQGP properties (hot QCD)

Precision measurements on focused energiesMap out the QCD phase structure

Precision measurements on pA and eAStudy QCD in cold matter

RHIC as an Exotic/Antimatter Machine

Science 328, 58 (2010)

STAR discovers the first anti-strange anti-nucleus

Nature 473, 353 (2011)

STAR discovers the heaviest anti-nucleus(later confirmed by ALICE)

RHIC as an Exotic/Antimatter Machine

Science 328, 58 (2010)

STAR discovers the first anti-strange anti-nucleus

Nature 473, 353 (2011)

STAR discovers the heaviest anti-nucleus(later confirmed by ALICE)

A. Tang, Rutherford Centennial Conference 2011

MA Lisa - primordial QCD Matter in LHC Era - Cairo,

Egypt - Dec 2011

PHENIX Open Heavy Flavor: eHF

One of the most surprising results from RHIC

Separating charm and bottom is the key to understand the mass

hierarchy of energy loss.

Au+Au

PRC 84 (2011) 044905 Electrons from Heavy quarks suppressed, and they flow.

Collective behavior is apparent in eHF; but HF v2

is lower than v2 of  0

for pT > 2 GeV/c.

Decomposition of the DCA Distributions

- VTX provides another new capability:

• Measure distance of closest approach to separate charm and bottom components of heavy flavor spectra

• Charm and Bottom events generated by PYTHIA are convoluted with DCA resolution to obtained expected DCA distribution shapes.

- Charm to bottom ratio is obtained from the fit to the DCA distribution of measured electrons:

Nuclear Modification of Charm RAA (ce)

Au+Au centrality: Min-Bias

No simple mass hierarchy in heavy flavor

RAA (be) < RAA (ce)

Nuclear Modification of Charm and Bottom

Summary CB

• First measurements of Charm and Bottom separately in heavy ion collisions at RHIC achieved

• In p+p, FONLL prediction of b/(b+c) agrees with the data

• In Au+Au, RAA(be) is strongly suppressed

• Most theory predictions of RAA(be) > RAA(ce) are not supported by our data

PHENIX-VTX opens new era of heavy flavor physics at RHIC

Thank you !

BackupBackup

Probing Hot dense matter with collision geometry control

38

PID’ed v2 in Au+Au and U+U

39

PID’ed v2 in Au+Au and U+U

40

Flattening of v2 at low pT for (anti) protons in UU

PID’ed v2 in Au+Au and U+U

41

LHC

Similar radial flow at RHIC and LHC

Strong radial flow in Tip-Tip enriched events

42

Tip-tip

0–2% 6–10%

Strong radial flow in Tip-Tip

43

Tip-tip

0–2% 6–10%

Flattening appears only in 0-2%

Strong radial flow due to geometry or higher energy density?

Beyond viscosity, a stunner: collectivity of… what?

mass scaling becomes baryon/meson systematic @ ~ 1 GeV

hmm.... what’s the difference between baryons and mesons...?

200 GeV

200 GeV A stunner: collectivity of… what?

mass scaling becomes baryon/meson systematic @ ~ 1 GeV

bulk dynamics of colored degrees of freedom!but...•“constituent quarks” are not partons!•where are the gluons? (In quark “dressing”?)

flowing constituent quarks “coalescing” into hadrons

nq = Number of Constituent Quarks (NCQ)

RAA (be) =

RAA of Bottom Extraction

x

RAA (be) =

RAA of Bottom Extraction

x

RAA (be) =

RAA of Bottom Extraction

x

RAA (be) =

RAA of Bottom Extraction

x

Elliptic Flow for different particles

STAR PRC 72 (05) 014904 200 GeV Au+Aumin-bias

v2 is different for different particles

Hydro

by H

uovin

en e

t al.

hydro

tuned t

o fi

t ce

ntr

al

spect

ra d

ata

.

First time hydro works: suggests early thermalization

- = 0.6 fm/c = 20 GeV/fm3

•Pure hydrodynamicalmodels including QGPphase describe ellipticflow for manyspecies

QGP-almost perfect fluid

Mirko Planinić

LHC Days in Split 2012

52

The complicated observed flow pattern in v2(pT) for hadrons

is predicted to be simple at the quark level underpT → pT /n

v2 → v2 / n ,

n = (2, 3) for (meson, baryon)

Works for p, (, K0s, , ,

)2cos( )( 21 2

2

T

T

pvddp

Nd

Constituent quark scaling

Constituents of QGP are partons

Mirko Planinić

LHC Days in Split 2012

v2 – Cu-Cu vs Au-AuPhys. Rev. C 81 (2010) 44902

Significantly smaller v2 in Cu-Cu than in Au-Au for given centrality

Scales with v2(Npart)

Large non-flow effects at high pT

Greater non-flow effects in Cu-Cu.

Mirko Planinić

LHC Days in Split 2012

Jet correlations in proton-proton reactions.

Strong back-to-back peaks.

Jet correlations in central Gold-Gold.

Away side jet disappears for particles pT > 2 GeV

Azimuthal Angular Correlations

Jet quenchingJet quenching

Mirko Planinić

LHC Days in Split 2010

Summary of what we learnedSummary of what we learnedat RHICat RHIC

Mirko Planinić

•Energy density in the collision is way above that where hadrons can exist•p-p reference measurements are well understood•Large suppression of high pT hadrons •Away side jets are suppressed•Cold nuclear matter effects on jets are small •The medium has quark and gluon degrees of freedom in initial stages•The QGP is flowing like an almost “perfect” liquid

We have created new state of matter at RHIC the QGP

High pT results can be explained as due to significant partonic energy loss in the QGP before fragmentation

Heavy ions at the LHCHeavy ions at the LHC

What are the initial conditions Is gluon saturation seen?Is v2LHC < v2RHIC ? Time evolution of the mediumIs QGP still strongly coupled? Behaving like a perfect liquid or more gas like?Energy loss similar to at RHIC? What is mass/flavor dependence of the Eloss? Heavy flavor copiously produced at RHIC?

RHICs higherluminosity andlonger runningtime keep it competitive

The expectation:LHC plasma hotter, denser, longer lived

Mirko Planinić

LHC Days in Split 2010

With the LHC and RHIC programs running in parallel the 2010’s promise an exciting decade for

Relativistic Heavy-Ion Collision Research

Thank you !

Mirko Planinić

LHC Days in Split 2010

n=2 RXNn=3 RXNn=4 RXNn=2 MPCn=3 MPC