Signatures of phase transitions in high energy collisions & NICA project

8.9.2011 Richard Lednicky New Trends , Alushta, Ukraine

-Thermal hadron production & phase diagram- Evidence for deconfinement at SPS, RHIC & LHC- Call for the new generation experiments- Fluctuation signature of the CEP- Femtoscopic signature of the QGP 1-st order PT- Project NICA - Conclusions

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March 2009

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4

Exp.: Thermal f-o (T - μB):

SPS

RHIC

SPS

RHICnantiparticle nparticle

5

Thermal Model

T 165 MeV

B 0 nantiparticle nparticle

6

1st order PT

crossover

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Lattice says: crossover at µ = 0 but CEP location is not clear

CEP: T ~ 160-170 MeV, μ B > 200 MeV

& MPD @ NICA/JINR

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Critical opalescenceApril,

Water liquid-gas CEP: 374 °C and 218 atm

Energy Range of NICA The most intriguing and unexplored region of the QCD phase diagram:

Highest net baryon density

Onset of deconfinement phase transition Strong discovery potential: a) Critical End Point (CEP) b) Chiral Symmetry Restoration с) Hypothetic Quarkyonic phase

Complementary to the RHIC/BES, CERN, FAIR and Nuclotron-M experimental programs

Comprehensive experimental program requires scan over the QCD phasediagram by varying collision parameters : system size, beam energy andcollision centrality

NICA NICA

Nuclotron-M

RHIC-BES

QCD phase diagramQCD phase diagram

Deconfined matter (high ,T,nB): >1 GeV/fm3, T>150 MeV or nB>(3-5)n0

- Strangeness enhancement & K/pi horn- Plateau in mT (pT

2+m2)1/2 in the entire SPS energy range- J/ suppression - UrQMD: predicts too small tr. flow at top SPS energies too large femtoscopic radii & too large Rout /Rside

NA49: anomalies in hadron production:

“Horn” – sharp maximum in the K+/pi+ or strangeness-to-entropy ratio in the transition region

“Step” - plateau in the excitation function of the apparent temperature or mt of hadrons

NA50: anomalous J/suppression in central A+A

Quarkonium suppression by color screening

Evidence for deconfinement at SPS

HG Mixedphase

QGP

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momentum correlations of emitted particles are sensitive to space-time structure of the source due to QS & FSI

CF=1+(-1)Scos qx

p1

p2

x1

x2

nnt , t

, nns , s

2

1

0 |q|

1/R0

total pair spin

2R0

KP’71-75: Correlation Femtoscopy

exp(-ip1x1)

x = x1-x2

q = p1-p2

Fermi’34

pion

Kaon

Proton

, , Flow & Radii x-out, y-side, z-long

← Emission points at a given tr. velocitypx = 0.15 GeV/c 0.3 GeV/c

px = 0.53 GeV/c 1.07 GeV/c

px = 1.01 GeV/c 2.02 GeV/c

For a Gaussian tr. density profile: (r) ~ exp(-r2/2RG

2)

and a linear flow velocity profile: F (r) = 0 r/ RG

0.73c

Rz2 2 (T/mt)

Rx2= x’2-2vxx’t’+vx

2t’2

Rz = evolution time Rx = emission duration

Ry2 = y’2

Ry2 = RG

2 / [1+ 02 mt /T]

Rx , Ry 0 = tr. flow velocity pt –spectra T = temperature

t’2 (-)2 ()2

BW: Retiere@LBL’05

Femto-puzzle I

Contradiction with transport and simple hydro calcul.

- Small space-time scales

- their weak energy dep.

- Rout/Rside ~ 1

Basically solved due to the initial flow increasing with energy (likely related to the increase of the initial energy density and partonic energy fraction)

AGSSPSRHIC: radii

Elliptic flow v2 vs energy increasing fraction of the partonic matter & a saturation on the ideal liquid level at the top RHIC energy

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v2/ε vs particle density in the transverse plane

IDEAL

v2 for midrapidity 25% most central collisions

AGSSPS

RHIC

Hydro expansion transfers the initial spatial eccentricity into elliptic flow v2

v2

Constituent quark number scalingof elliptic flow partonic collectivityin a relativistic quantum liquid

Strong high pT suppression in hadron production highly opaque

matter for colored probes (not for ’s)

sQGP matter at RHIC

Evidence for deconfinement at RHIC- Large elliptic flow: v2/ close to ideal liquid value at top RHIC energies - CQNS of v2

- CME (Chiral Magnetic Effect)- Jet quenching

CQNS of v2 not valid below 39 GeV

News from BES @ RHIC: Quark Matter 2011

(LPV)

News from BES @ RHIC: Quark Matter 2011

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: Jet Quenching at RHIC

Universal freeze-out density

Evidence for deconfinement at LHC

First direct evidence of strong jet quenching observed in LHC HI collisions by ATLAS and CMS

Observed similar differential elliptic flow v2(pt) as at RHIC increased /s at LHC compensating the increase of and T : from liquid to gas ?

Song, Bass, Heinz, arXiv:1103.2380v2 in Hydro+UrQMD transport code/s = 0.16 at RHIC 0.20-0.24 at LHCHeinz, Shen, Song, arXiv:1108.5323 but: 0.16 at LHC

Xu, Ko, arXiv:1101.2231v2 in AMPT multiphase transport modelparton = 10 mb at RHIC 1.5 mb at LHC/s ~ (T2parton)-1

increased T at LHC more thancompensated by decreased parton

Bhatt, Mishra,Sreekanth, arXiv:1103.4333/s with T may lead to cavitation(gas bubbles) hydro at LHC applic. up to 2 fm/c only ?

Tomasik, Levai, arXiv:1104.3262~25% of v2 may come from hard partons /s > 0.20-0.24 at LHC

Ridge effect

Dense matter (collective flows) also in pp collisions at LHC (for high Nch) ?

- pt increases with nch and particle mass- BE CF vs nch and pt points to expansion at high nch

- Ridge effect observed in angular correlations at high nch

R(kt) at large Nch expansion

Color flux tubes longitudinal translation invariance of transverse flows

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Origin of Ridge in Rel. HICs:

Similar picture in HM pp: Increasing number of color flux tubes with multiplicity similar energy densities at HM pp as in Rel. HICs similar tr. Flows (Ridge)

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EPOS+hydro:

Ridge

EPOS w/o hydro:

No Ridge

Ridge in HM pp 7 TeV pt= 1-3 GeV/c K.Werner et al. arXiv:1011.0375

Evidence for the onset of deconfinement @ low SPS energies √sNN ~ 7 GeV & sQGP matter @ RHIC

2nd generation HI experiments (STAR, NA61, ALICE, ATLAS, CMS) continue the exploration of the QCD phase diagram

But, a further research program in studying the QCD phase diagram with the existing detectors appears to have drawbacks due limitations either in accelerator parameters (energy range, luminosity) or by constrains in experimental setups (acceptance, event rates, etc..)

Lessons from the 1st generation HI experiments

Motivation for the next generation of HI experiments

3rd generation experiment with dedicated detectors are required for more sensitive and detailed study

CBM @ FAIR/SIS-100/300Fixed target, E/A=10-40 GeV, high luminosity,But, max. energies in 2018!

STAR/PHENIX @ BNL/RHIC. Originally designed forhigher energies (ssNNNN > 20 GeV), low luminosity for LESprogram L<1026 cm-2s-1 for Au79+, too few energies.

NA61 @ CERN/SPS. Fixed target, non-uniformacceptance, few energies (10,20,30,40,80,160A GeV),poor nomenclature of beam species

MPD @ JINR/NICA. Collider, small enough energy steps in the range ssNNNN = 4-11 GeV, a variety of colliding systems, L~1027 cm-2s-1 for Au79+ at 9 GeV.

2nd generation HI experiments

3rd generation HI experiments

ALICE, ATLAS, CMS @ CERN/LHC Too high energies (ssNNNN > ~1 TeV ),poor nomenclature of beam species

Why the NICA and FAIR energy range is so important

The energies of the NICA and FAIR sit right on top of the region

where the baryon density at the freeze-out is expected to be the highest. It will thus allow to analyze the highest baryonic density under laboratory conditions.

Also, in this energy range the system occupies a maximal space-time volume in the mixed quark-hadron phase (the phase of coexistence of hadron and quark-qluon matter similar to the water-vapor coexistence-phase).

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CP:

___

______

_________

s==0 for Gaussian distr.

News from BES @ RHIC: Quark Matter 2011

(contrary to fixed target NA49 data)

News from BES @ RHIC: Quark Matter 2011

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Cassing – Bratkovskaya: Parton-Hadron-String-Dynamics

Perspectives at FAIR/NICA energies

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CEP signals in multiplicity and pt fluctuations for ξ =3 and 6 fm

pt 10 MeV/c for ξ = 3 fm 2.5 MeV/c for NA49 acc.= 0.24M. Stephanov .. ’99 B. Berdnikov .. ‘00ξ <~3 fm due to finite fireball lifetime pt < 0.5 MeV if max partonic energy fraction ~20% as expected in PHSD

assuming CEP at T=162 MeV µB=360 MeV & Gaussian fluctuation shape with the width of 10 MeV in T 30 MeV in µB

pt = (D(∑pti)/‹N›)1/2-(D(pt))1/2

ω= D(N)/‹N›

ξ =6 fm

3 fm

Femtoscopic signature of QGP onset3D 1-fluid Hydrodynamics

Rischke & Gyulassy, NPA 608, 479 (1996)

With 1st order Phase transition

Initial energy density 0

Long-standing signature of QGP onset:

• increase in , ROUT/RSIDE due to the Phase transition

• hoped-for “turn on” as QGP threshold in 0 is reached

decreases with decreasing Latent heat & increasing tr. Flow

(high 0 or initial tr. Flow)

Femto-puzzle II

No signal of a bump in Rout near the QGP

threshold (expected at AGS-SPS energies) !? –

likely solved due to a decrease of partonic

phase at these energies

3

NICA : Nuclotron-based Ion Collider fAcilityLocation : JINR, Dubna

New flagship project at JINR Based on the technological

development of the Nuclotron facility Optimal usage of the existing

infrastructure Modern machine which incorporates

new technological concepts First beams expected in 2016

NICA advantages: Energy range ssNNNN = 4-11 GeV - highest baryon density Rich nomenclature of beams : from p to Au Highest luminosity : Au+Au up to 1027

NICA LayoutNICA Layout

Facility Scheme and Operation Scenario

Bldg #205

Bldg #1

Collider

C = 500 m

SPI & LU-20 (“Old” linac)

KRION-6T & HILac

Synchrophasotron yoke

MPD

Spin Physics Detector (SPD)

2.5 m

4.0 m

Booster

Nuclotron

Fixed targetexperiments

Nuclotron-type SC magnets for Booster

Booster magnet yoke manufacturedBooster magnet yoke manufactured

3838

The NICA design passed the stage of concept formulation and is presently under

detailed simulation of accelerator elements parameters, development of working project, manufacturing and construction of prototypes, preparation of the project for state expertise

in accordance with regulations of Russian Federation.

The project realization plan foresees a staged construction and commissioning of accelerators forming the facility. The main goal is the facility commissioning in 2016.

NICA construction schedule2010 2011 2012 2013 2014 2015 2016

ESIS KRIONLINAC + channelBooster + channelNuclotron-MNuclotron-M → NICAChannel to colliderColliderDiagnosticsPower supplyControl systemsCryogenicsMPDInfrastructure

R&D Design Manufactrng Mount.+commis. Commis/opr Operation

Conclusions • Some indications of deconfined partonic matter come from SPS,

RHIC & LHC HIC at √sNN > 10 GeV (µB < 400 MeV);

particularly, FO points (T, µB) calculated within Thermal Model seem to be close to QGP phase boundary for small µB < 400 MeV

• Absence of fluctuation & femtoscopic signals of CEP and 1-st order PT at √sNN < 10 GeV is likely due to a dramatic decrease of partonic phase with decreasing energy

• Search for the effects of QGP 1-st order PT (onset and CEP) can be successful only in dedicated high statistics and precise experiments like NICA and FAIR

• NICA is under construction in JINR and its startup is supposed in 2016

40Welcome

41

if added heavy resonances (motivated by e+e-) +

News from BES @ RHIC: Quark Matter 2011

AGSSPSRHIC: radii

STAR Au+Au at 200 AGeV

0-5% central Pb+Pb or Au+Au

Clear centrality & mt dependence Weak energy dependence

R ↑ with centrality & with mt only Rlong slightly ↑ with energy

Rside R/(1+mt F2/T)½

Rlong (T/mt)½

tr. collective flow velocity F Evolution (freeze-out) time

Femtoscopy of Pb+Pb at LHC arXiv:1012.4035

All radii increase with Nch from RHIC to LHC multiplicity scaling of the correlation volume

universal freeze-out density

Freeze-out time f from Rlong=f (T/mt)1/2

The LHC fireball: - hotter- lives longer &- expands to a larger size

FREEZE-OUT AND PHASE DIAGRAMS

Ivanov, Russkikh,Toneev ’06 :

Randrup, Cleymans ‘06 :

At lower energies the system spents an essential time in the mixed phase

The freeze-out baryon density is maximal at sNN= (4+4) GeV covered by NICA and FAIR

NICA&FAIRssNNNN = 9 AGeV = 9 AGeV

SNN = 4-11 GeV is a most promising energy region to search for mixed

phase & critical end-point

Besides NICA & FAIR also RHIC & SPS plan to partly cover this energy range

Critical end-point

1st order PT

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Quark Matter 2011May 23, 2011 47

Fluctuation Observables, dyn

• NA49 uses the variable dyn dyn sign data

2 mixed2 data

2 mixed2

is relative width of K / distributions is the reduced width of K/p distribution

Terence Tarnowsky, QM’2011 48

Fluctuation Observables, dyn

• STAR uses a different fluctuation observable, dyn.

• Introduced to study net-charge fluctuations.

• Measures deviation from Poisson behavior.

• It has been demonstrated that,

dyn,K NK NK 1 NK

2 N N 1 N

2 2NKN

NK N

dyndyn 2

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EPOS+hydro: energy density & radial velocity @ s = 0, =1.3 fm/c HM pp 7 TeV very fast expansion; drops from ~50 to ~3 GeV/fm3 in 1.3 fm/c and radial velocity near boundary achieves 80% c

Similar collective expansion expected in HM pp & AA

Energy density GeV/fm3

Radial velocity %c

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First observation of new phenomena in p-p

Several papers on possible interpretations. New set of measurements to understand better the dynamics. It will be very interesting to compare the measurements in pp and heavy-ions modes.

Observation of Long-Range Near-Side Angular Correlations in Proton-Proton Collisions at LHCCMS Collaboration, JHEP 9 (2010) 1 arXiv:1009.4122

Ridge

Femtoscopy of pp collisions at LHC vs EPOS modelwith/without hydro

without hydro

too small factor of 3

without hydro

Nmin bias 5*Nmin bias

arXiv:1104.2405: EPOS with hydroCollective flow in pp increases with Nch

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r

Input: 1, 2=1-1, r1=15, r2=5 fm

1-G Fit: r ,

1

2-G Fit: 1, 2, r1,r2

r1

r2

2

1

1

1

Typical 1-G (3d) fit:

e.g., NA49 central

Pb+Pb 158 AGeV

Y=0-05, pt=0.25 GeV/c

Rout=5.29±.08±.42

Rside=4.66±.06±.14

Rlong=5.19±.08±.24

=0.52±.01±.09

Radii vs fraction 1 of the large scale: very weak sensitivity

solving Femtoscopy Puzzle II

1

1

53

Imaging

54

The NICA Project Goals

1a) Heavy ion colliding beams 197Au79+ x 197Au79+ at sNN = 4 ÷ 11 GeV (1 ÷ 4.5 GeV/u ion kinetic energy )

at Laverage= 1E27 cm-2s-1 (at sNN = 9 GeV)

1b) Light-Heavy ion colliding beams of the same energy range and luminosity

2) Polarized beams of protons and deuterons in collider mode:pp spp = 12 ÷ 27 GeV (5 ÷ 12.6 GeV kinetic energy )

dd sNN = 4 ÷ 13.8 GeV (2 ÷ 5.9 GeV/u ion kinetic energy )

Laverage 1E30 cm-2s-1 (at spp = 27 GeV)

3) The beams of light ions and polarized protons and deuterons for fixed target experiments: Li Au = 1 4.5 GeV /u ion kinetic energyp, p = 5 ÷ 12.6 GeV kinetic energy d, d = 2 ÷ 5.9 GeV/u ion kinetic energy

4) Applied research on ion beams at kinetic energy

from 0.5 GeV/u up to 12.6 GeV (p) and 4.5 GeV /u (Au)

5656

Nuclotron (45 Tm)injection of one bunch

of 1.1×109 ions,acceleration up to 1 - 4.5 GeV/u max.

Linac ЛУ-20

Today

Facility Scheme and Operation Scenario

Ion sources

Fixed Target Area

5757

Nuclotron (45 Tm)injection of one bunch

of 1.1×109 ions,acceleration up to 1 - 4.5 GeV/u max.

Linac LU-20Ion sources

Fixed Target Area

Booster (25 Tm)1(2-3) single-turn injection,

storage of 2∙(4-6)×109,acceleration up to 100 MeV/u,electron cooling, acceleration

up to 600 MeV/u

Facility Scheme and Operation Scenario

Tomorrow

Stripping (80%) 197Au32+ => 197Au79+

Two SCcollider rings

Linac HILac KRION

IP-1

IP-2

MPD Physics. Tasks and challenges bulk observables (hadrons): 4 particle yields (OD, EOS) event-by-event fluctuation in hadron productions (CEP) femtoscopic correlations involving π, K, p, Λ (OD) directed & elliptic flows for identified hadron species (EOS,OD) multi-strange hyperon production : yields & spectra (OD, EOS) electromagnetic probes (CSR, OD) hypernuclei (DM)

OD – Onset of Deconfinement CEP – Critical End PointDM – Dense Matter

Challenges: Vast nomenclature of colliding systems – from p+p to Au+Au simultaneous observation of a variety of phenomena Small effects over large kinematical range, sensitivity to acceptance

constrains (‘correlations & fluctuations’ studies) Pattern recognition in high track multiplicity environment

CSR – Chiral Symmetry RestorationEOS – Equation Of State

12

Active volume 5 m (length) x 4 m (diameter)

Magnet 0.5 T superconductor

Tracking TPC & straw EndCapTracker & silicon pixels (IT) for vertexing

ParticleID hadrons(TPC+TOF), 0, (ECAL), e+e-(TPC+TOF+ECAL)

Centrality & T0 timing ZDC FD

MPD Advantages: Hermeticity, homogenous acceptance (2in azimuth), low material budget Excellent tracking performance and powerful PID High event rate capability and careful event characterization

The MPD Apparatus