Od odkrycia do poznania wlasnosci plazmy kwarkowo-gluonowejnauka/konw/prez_090312.pdf · Grazyna...

Grazyna Odyniec

Od odkrycia – do poznania

wlasnosci plazmy kwarkowo-gluonowej

Grazyna Odyniec / LBNL, Berkeley

Plan :

Plazma ? CERN SPS, RHIC, LHC, ...

Wykres fazowy silnie oddzialywujacej materii jadrowej - #1 fizyki jadrowej

Badanie struktury - eksperyment przejmuje prowadzenie !

BES @ RHIC, FAIR @GSI, LHC, …

Grazyna Odyniec Konwersatorium, Politechnika Warszawska, Wydzial Fizyki, 12 marzec 2009 2

CERN in 2000 !


RHIC discovery !


DETOUR (1): Quantum Chromodynamics

1) Quantum Chromodynamics (QCD) is the established theory of strongly interacting matter.

2) Gluons hold quarks together to form hadrons:

3) Gluons and quarks, or partons, typically exist in a color singlet state: confinement.

baryonmeson


DETOUR (2): Quark Gluon Plasma

- The confinement:

Quarks are the basic building blocks of matter.

No free quarks are seen, confined within hadron:

v0 ~ 1 fm3, 0 ~ 0.16 fm-3, 0 ~ 0.15 GeV/fm3

- Heavy ion collisions: Large, hot, and dense system

v ~ 1000 fm3 = 1000 v0

>> 3 fm-3 ~ 20 0 QGP(?) >> 3 GeV/fm3 ~ 20 0

Quarks and gluons are ‘freely’ moving in a large volume

New form of matter with partonic degrees of freedom

- Connection with other fields

cosmology, origin of the universe, evolution of the universe

quantum statistics with partons


DETOUR (3): Confinement Potential

T < T conf

T > T conf

constant potential

r

V(r,T)The potential between quarks is a

function of distance. It also depends

on

the temperature.

1) At low temperature, the potential

increases linearly with the distance

between quarks

quarks are confined;

2) At high temperature, the

confinement potential is ‘melted’

quarks are ‘free’.

Note: It is not clear at all if there is a

critical ‘temperature’ in high energy

collisions


DETOUR (4): Lattice QCD Predictions

Left: Large increase in energy density at TC ~ 170 MeV.

Not reach the non-interacting S.B. limit.

Right: Heavy quark potentials are melted at high temperature.

F. Karsch et al. Nucl. Phys. B524, 123(02). Z. Fodor et al, JHEP 0203:014(02).

C.R. Allton et al, Nucl. Rev. D66, 074507(02). F. Karsch, Nucl. Phys. A698, 199c(02).

Temperature

Energy densityHeavy quark potential


Phases of Water

CP1st order phase

transition

cro

ss-o

ver


QCD Phase Diagram

QCD: The phase diagram of

strongly interacting matter is under study

(relativistic particles)

Cross-over

1st order phase transition

CP

WATER: the phase diagram of water

is well established (non-relativistic

particles)


Phases of strongly interacting matter (?)

SPS, RHIC, LHC: high temperature, low baryon density

AGS, GSI: moderate temperature, high baryon density

QGP

HG


From Fermi’s notes on thermodynamics:

!

Grazyna Odyniec Konwersatorium, Politechnika Warszawska, Wydzial Fizyki, 12 marzec 2009

!


hep-lat/0701002v1

Given the very significant theoretical difficulties,

data may lead the study of QCD phase diagram …

Lattice - green points !

mB<500

Theory


• How do we do it ?

–High-energy nuclear collisions

–RHIC


High-energy Nuclear Collisions

PCM & clust. hadronization

NFD

NFD & hadronic TM

PCM & hadronic TM

CYM & LGT

string & hadronic TM

S. B

ass

Initial

conditions Initial high Q2

interactions Partonic matter -

QGP

- The hot-QCD Hadronization and Freeze-out

tt=0

(1) Chemical freeze-out

(2) Thermal freeze-out


RHICBRAHMSPHOBOS

PHENIXSTAR

AGS

TANDEMS

Relativistic Heavy Ion Collider (RHIC)Brookhaven National Laboratory (BNL), Upton, NY

v = 0.99995c = 186,000 miles/sec

Au + Au at 200 GeV

Animation M. Lisa


STARSTAR

RHIC experimentsPHENIX

Focus:

rare probes , e±, m

Partial coverage

High-granularity calorimetry

and tracking

Forward muon detectors

STAR

Focus:

global observables

Large volume TPC (2p)

+EM calorimetry (coarse)


STAR Collaboration


Peripheral Event

STAR

Au + Au Collisions at 130 GeV

(real-time Level 3)

Grazyna Odyniec Konwersatorium, Politechnika Warszawska, Wydzial Fizyki, 12 marzec 2009 21STAR

Mid-Central Event

Au + Au Collisions at 130 GeV

(real-time Level 3)


Au + Au Collisions at RHIC

STAR

Central Event

(real-time Level 3)


(1) What did we learned ?

•Elliptic Flow

Probing hot and dense matter (QGP ?) with hard probes

Grazyna Odyniec

Lawrence Berkeley National Laboratory

Konwersatorium na Wydziale Fizyki Politechniki Warszwskiej, 24 maja 2007


Azimuthal Anisotropy - Elliptic Flow

Reaction-plane: x-z plane

Origin: spatial anisotropy of the system when created and rescattering of evolving system

spatial anisotropy momentum anisotropy

Almond shape overlap region

in coordinate space

y2 x2

y2 x

2

2cos2 vx

y

p

patan

x space momentum


Elliptic Flow

25

Large Elliptic Flow: A Signal of Strong Space-Momentum Correlations

Space Momentum

2cos2 vx

y

p

patan

y2 x2

y2 x

2


“Perfect fluid” ?

Detailed analysis of v2 for different mass

shows good agreement with ideal (zero

viscosity, l=0) hydrodynamics

“perfect fluid” ?

Separation between baryon and meson

band

Note: ’s flow ! (also W’s) …as light h

flow developed in pre-hadronic stage

DECONFINEMENT !!!

(a lot of scatterings …thermalization ?)


Partonic degrees of freedom

Scaling flow parameters by quark

content nq (baryons=3, mesons=2)

resolves meson-baryon separation

of final state hadrons

“liquid” of partons !

(1) v2 developed at pre-hadronic state –

indicates a lot of interactions between q

and g, some thermalization ?

(2) deconfinement

(3) Novel hadronization process at RHIC


A short summary (I) :

• mT-Nq scaling

• Partonic collectivity

• Deconfinement

Hot and dense matter with partonic collectivity has been

formed at RHIC


(2) What did we learned ?

•Jets


Jets in heavy-ion collisions

• Partons lose energy due to induced gluon radiation (Bjorken, Gyulassy, X.N. Wang, …)– Energy loss is measure of gluon density

Probe energy loss via leading hadrons (2) and di-hadron correlations (2)

hadrons

hadrons leading

particle

suppressed

leading

particle

suppressed

q

q

hadrons

q

q

hadrons

leading

particle

qq

p+p Nuclear Medium

Quenched dijets


Not easy !

p+p dijet How to find it here ?


How to measure ?

1. RAA: Compare A+A and p+p collisions


Jets are quenched, part I - RAA

ddpdT

ddpNdpR

T

NN

AA

T

AA

TAA/

/)(

2

2

Jets (color-

charged)

Photons (color-

neutral)


Jets are quenched, part II - correlations

STAR, Phys Rev Lett 91, 072304

Hard recoil hadrons

cos()

STAR, Phys Rev Lett 95, 152301

All recoil hadrons


A short summary (II) :

• Photons are not suppressed

good ! They do not interact with medium

• Hadrons are not suppressed in peripheral collisons

good ! Medium not dense

• Hadrons are suppressed in central collisions

huge: factor 5 !

• Azimuthal correlation shows ~ complete absence of :”away-side” jet

partner in hard scatter is absorbed in the dense medium

High pt suppression - Matter is opaque !


Top discoveries at RHIC

• Strong elliptic flow

– collective flow of created matter

– partonic collectivity

– deconfinement

• Jet quenching

– Energy loss of high pt partons in hot and dense medium

– Medium response – ridge ?

• Production mechanism at medium pt via

recombination/coalescence (not via fragmentation)

• Strongly coupled QGP = sQGP

not wQGP – surprise , surprise !!!


First point – 100 years ago !

In 1911, Rutherford discovered the nucleus,

making him the first nuclear physicist

100 years later, RHIC will scan for the next

landmark on the nuclear matter phase

diagram: the critical point

One Century of Nuclear Physics


Summarizing the situation :

• Now:

sQGP produced in A+A at RHIC at top energies

(hot and dense matter with partonic dof)

• Problem:

we still don’t know much about sQGP !

• Future:

properties of sQGP– RHIC, LHC, …?

boundary between hadronic and partonic phases

(where is a phase transition ?) – RICH, Fear, …

CP

(wQGP

)


Beam Energy Scan at RHIC:RHIC: Ideally Suited 5-50 GeV


PID matters: Phase Transitions

Rutherford's discovery of the nucleus in 1911 relied on state-of-the art technology

developed by Hans Geiger to count alpha particles. The state-of-the-art technology at the

heart of STAR's Time-of-Flight upgrade significantly increases the possibility that STAR will

locate that other landmark on the nuclear matter map: the critical point.


Particle Identification at STAR

STAR TPC

STAR ToF

STAR EMC

STAR HFT

Neutral particles Strange Jets Heavy Quark

hyperons Hadrons

Multiple-fold correlations among the identified particles!

e, μ

π

K p d

TPC ToF TPC

Log10(p)

http://www.star.bnl.gov/protected/spectra/ruanlj/TOFrpaper/tofr_beta_p_prplot.gif


√sNN (GeV) Rate

(Evts/sec)

10 hr days

for 1 M Evts

5.0 0.8 34

7.7 3 9

11.5 10 3

17.3 33 0.8

27 92 0.3

39 190 0.15

These energies are all logarithmically equally spaced (constant multiplicative factor of ~1.5)

between √sNN = 5.0 and 62.4 GeV, except for 39 GeV, which is shifted slightly from 41 GeV to

match existing pp data.

21

Run 10, fall 2009 – energies likely to be proposed by STAR


Search for turn-off of major sQGP signatures already established at top RHIC energies (our least speculative objective).

Search for evidence of critical point.

Search for phase transition signatures of the type that appear and then disappear as the beam energy is scanned.

6

STAR run plan for BES – physics objectives


STAR experience with Low Energy RHIC running2001: 19.6 GeV Au+Au

2004: 22.4 GeV Cu+Cu

2007: 9 GeV Au+Au

2008: 9 (5) GeV Au+Au !

E802 PRL81, 2650 (1998)E866 PLB476, 1 (2000)E917 PLB490, 53 (2000)NA44 PLB471, 6 (1999)WA98 PRC67, 104906 (2003)NA49 PRC66, 054902 (2002)NA49 EPJC33, S621 (2004)NA49 arXiv:0710.0118v2PHENIX PRC69, 034909 (2004)PHENIX PRL88, 242301 (2002)STAR PRL92, 112301 (2003)STAR PLB595, 143 (2004)

Preliminary

Preliminary

Sufficient data to extract ratios, flow

velocity, HBT radii, v2

Data fit into systematics

D. Cebra QM2008


2008: low energy run with 9.2 GeV Au+Au

Injecting and colliding Au+Au√sNN = 9.2 GeV, a few hours -> 4K good events !

Short test @√sNN = 5 GeV allowed study of beam optics


Vertex Z (cm)

Au+Al Au+Al

Au+Be

Au+Au and Au+Al collisions !V

ert

ex Y

Vertex X

Au+Au collisions

Au+Beampipe collisions

Investigated primary vertex location:They are “real”collisions.

R. Reed

Can see the change in beampipe material and thickness


Lambda

invariant mass

(SQM 2008)

9.2 GeV Au+Au, March 2008 – preliminary analysis


• The unique RHIC energy scan program will map the QCD

diagram in sNN =5-50 GeV, (corresponding to mB ~ 600-150

MeV)

• STAR is tested and ready (DAQ, trigger, … all)

• First run – fall 2009

• Informal discussion between STAR and PHENIX

• Late-breaking news:likely $4.5M Economic Stimulus funding for RHIC electron cooling, with an order of

magnitude intensity increase down to √sNN ~ 5 GeV, coming online in 2012-13 (a

“shovel ready” project).


What next (rather parallel) besides BES ?

vertical direction: T (mB~0)

QCD Phase Transition, CP,

BES/RHIC, FAIR/GSI, …

Har

d ph

ysic

s,

RH

IC II

,LH

C

Grazyna Odyniec

LHC

ATLAS

CMS

ALICE

p+p collisions @ 14 TeV (2009 ?)

Pb+Pb collisions @ 5.5 TeV (2010+)

ALICE is the dedicated Heavy-Ion experiment (high-density tracking and PID)

CMS and ATLAS are likely to participate in HI runs as well


LHC and ALICE !

Better environment for high-pt physics than RHIC

High-pt processes increase faster than soft background


ALICE installation (already historical pictures !)

Installation of TPC

Installation of Silicon

Inner Tracker

Installation of Beam Pipe

Inner tracker


ETjet>100 GeV ~ 106/year

Hard process rates at the LHCAnnual yields for Pb+Pb at LHC

Jet rates and kinematic reach

at LHC are huge

compared to RHIC

High statistics

measurements

over large kinematic range

for precision test of theory


Jet reconstruction at LHC

Jet yields at high energies (>50 GeV) are large

enough for full jet reconstruction

En

erg

y (

GeV

)

Full jet reco removes fragmentation bias

Study jet quenching (modified

fragmentation) in more detail

Jets accessible over large energy range

(50-200 GeV from full jet reco)

Validate jet quenching mechanism And more:

– Heavy quark jets

– -jet correlations (calibrate kinematics)

– Suprises?

ELHC ≈ 40 GeV

need ET,Jet~200 GeV for E>>E

100 GeV jet in central Pb+Pb


ALICE EMCal

Lead-scintillator sampling calorimeter

||<0.7, =110o

Shashlik geometry, APD photosensor

~13k towers (x~0.014x0.014)

US contribution to ALICE


SummaryThe initial expectation at RHIC of an ideal gas plasma of non-

interacting quarks and gluons is a distant memory.

Instead, something much more interesting has been found:

The most perfect fluid known, with equilibrium and dynamical

properties that are calculable from basic theory, perhaps including

string theory.

In the next five years:

BES program at RHIC

RHIC and detector upgrades

Run the LHC HI program (wQGP?)


THANKS !


ETRA SLIDES


Particle Identification in STAR

• TOF alone: (p,K) up to 1.6 GeV/c, p up to 3 GeV/c

• TOF+TPC(dE/dx, topology) up to 12 GeV (NIMA 558 (419) 2006)

log10(p)

log10(dE/dx)

TPC+TOF (completed in 2010)+EMC+Topology

Good quality PID over a broad range:

~ 0.2 – 12 GeV/c


BES at RHIC - access to large range of mB and T

advantage of collider geometry !

At fixed target geometry:

detector acceptance changes with energy

track density at mid-y increases fast with energy

-> technical difficulties in tracking

-explore a broad region of the QCD phase

diagram

-look for the evidence of ordered transition

-study the evolution with beam energy of the unusual medium properties found at RHIC

-do any of the partonic properties change or “turn off” ?

-new surprises in unexplored region …

produces systems with lower freezout temperatures and higher baryon densities


What should be measured during BES ?Mainly related to bulk properties

yields and particle ratios T vs mB,

particle spactra (pt, rapidity, …),

strangeness production (K/p, multistrange, …),

fluctuations and correlations of many varietes (K/p,<pt>, HBT,v2@CP,…)

flow (v1,v2,v4, …) with charged and identified particles,

signals of parity violation,

“lumpy”(“clumpy” ?) final state

prospect of data will “encourage” theorists to be more specific

Search for : - disappearance of partonic activities

- fluctuations, correlations

turn on and off signature of deconfinement


Colliders are a great choice for E-scanAcceptance

Acceptance for collider detectors is

totally independent of beam energy

• Occupancy for collider detectors is

much less dependent on beam

energy

• Less problems with track merging,

charge sharing hits etc..

π

K

STAR

Better control of systematics

Kπ

NA49

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