18.06.2010 Richard Lednický GDRE Nantes ‘2010 1

Physics at NICA

• Evidence for deconfinement at SPS & RHIC• Call for the new generation experiments• Thermal hadron production & phase diagram• Fluctuation signature of the CP• Femtoscopic signature of the QGP 1-st order PT:

searching for large scales• Spin physics at NICA• Conclusions

- Strangeness enhancement & K/pi horn- Plateau in <mT> in the entire SPS energy range- J/ suppression - UrQMD: 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

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 photons)

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- Jet quenching

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

2nd generation HI experiments (STAR, NA61) will soon 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

3nd 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

3nd generation HI experiments

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).

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

SPD

MPD

NICA complexNICA complex

NuclotronE/A = 1..5.5 GeVQ=+79

Booster2.109 ions/bunchE/A = 608 MeVQ=+32, electron cooling

Ion source+Linac2.109 ions/pulseE/A = 6.2 MeVQ = +32

ColliderBeams – p,d()..197Au79+

Collision energy – 4-11 GeVNo bunches – 2x17Luminosity: 1027 cm-2s-1(Au79+), 1032 (p)Interaction points – 2 (MPD and SPD detectors)

s

The MultiPurpose Detector isproposed for study of hot anddense baryonic matter in collisionsof heavy ions over mass rangeA=1-197 at a centre-of-massenergy √sNN = 4-11 GeV.

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Thermal Model

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

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13

!

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Lattice says:

crossover at µ = 0 but CP location is not clear

CP: T ~ 170 MeV, μ B > 200 MeV

QCD phase diagramQCD phase diagramThe most intriguing and little studiedregion of the QCD phase diagram:

Characterized by the highest net baryon density

Allows to study in great detail properties of the phase transition region

Has strong discovery potential in searching for the Critical End Point and manifestation of Chiral Symmetry Restoration

Recently became very attractive for heavy-ion community: RHIC/BNL, SPS/CERN, FAIR/GSI, NICA/JINR

Challenge: comprehensive experimental program requires scan over the QCDphase diagram by varying collision parameters : system size, beam energyand collision centrality

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

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CP:

___

______

_________

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

pt 40 (10) MeV/c for ξ =6 (3) fm 10 (2.5) for NA49 acc.= 0.24M. Stephanov .. ’99 B. Berdnikov .. ‘00

ξ <~3 fm due to finite fireball lifetime < 2 (.5) MeV if max partonic energy fraction ~20% as expected in PHSD

assuming CP 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›

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Cassing – Bratkovskaya: Parton-Hadron-String-Dynamics

Perspectives at FAIR/NICA energies

Elliptic flow energy dependence points to the increasing fraction of partonic matter with increasing energy & 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

Femtoscopic signature of QGP3D 1-fluid Hydrodynamics

Rischke & Gyulassy, NPA 608, 479 (1996)

With 1st order Phase transition

Initial energy density 0

Long-standing signature of QGP:

• 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

Femto-puzzle I

Small space-time scales at RHIC

energies – basically solved due to the

initial flow

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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

21 1

1

(r1)/0.06 fm

(1)/0.01

Typical stat. errors

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

in 1-G (3d) fit

Radii vs fraction 1 of the large scale: very weak sensitivity solving Femtoscopy Puzzle II

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Imaging

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Other physics at NICA.Study of density fluctuations in A+A collisions

High nucleon density region inside a nuclei due to density fluctuations (“fluctons”)

D.Blokhintsev, GETF 6, 995 (1958), A.M. Baldin et al. Sov. J. Nucl.Phys. 18, 79 (1973)

Flucton-flucton (nucleon-flucton) interactions in low-A nuclei collisions triggered by a midrapidity high-pt product ()

Study of the properties of dense medium:

Baryon clusterization in momentum space and emision time (femtoscopy)

Strangeness and resonace production

Exotic strange multibaryon states with ,p,,K0

Spin physics @ NICA. Protons’s spin

quark contribution

gluon contribution

Main quest: what is the distribution of nucleon spin among constituents? How quarks and gluons carry spin and orbital angular momentum?

Recent data (CERN, DESY, JLAB, SLAC):

G is less then speculated missing spin contribution (“spin crisis” continues)

New (precise) measurements of many (new) PDFs (Parton Distribution Functions) required

Lq, Lg – angular orbital momentum contributions (unknown)

0.3

|G| < 0.3

½ = ½ + G + Lq + Lg

NICA advantages:

Beams – p,d(), L ~ 1032 cm-2s-1 Polarization – transversal and longitudinal ( > 50%) Collision energy – up to √s = 25 GeV

Spin physics @ NICA (2)

Spin physics program with polarized beams at NICA:

Comprehensive studies of DY and J/ production processes (polarized and unpolarized) Spin effects in one and two hadron production processes Spectroscopy of quarkonia and diffractive processes

Spin physics @ NICA (3)

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sin(+S): access to transversity & Boer-Mulders PDFs Sissakian, Shevchenko, Nagaytsev,PRD 72 (2005), EPJ C46 (2006)

sin(-S): access to Sivers PDFs Efremov,… PLB 612(2005), PRD 73(2006)

Spin physics @ NICA: polarized MMT-DY

The SSA for 100k DY events: 3 years of running

Experiments on MMT-DY measurements

Experiment Status Remarks

E615 Finished Only unpolarized MMT-DY

NA10 Finished Only unpolarized MMT-DY

E886 Running Only unpolarized MMT-DY

RHIC Running Detector upgrade for MMT-DY measurements (collider)

PAX Plan > 2016 Problem with polarization (collider)

COMPASS Plan > 2010 Only valence PDFs

J-PARC Plan > 2011 low s (60-100 GeV2), only unpolarized proton beam

SPASCHARM

NICA

Plan?

Plan > 2015

s ~ 140 GeV2 for unpolarized proton beam

s ~ 670 GeV2 for polarized proton beams, high luminosity (collider)

p

Conclusions I• FO points calculated within Thermal Model seem to be

close to QGP phase boundary for small µB < 400 MeV (√s

NN > 10 GeV)

• Absence of fluctuation signal of CP and 1-st order PT at

µB > 400 MeV (√s NN < 10 GeV) is likely due to a dramatic decrease of partonic phase with decreasing energy

• This decrease solves also the Femtoscopic Puzzle II – Absence of clear Rout bump signal near the QGP threshold (expected at AGS-SPS energies)

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

• Good prospects for spin physics research at NICA32

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The strategic plans of JINR in HEP is targeting to

the development of home accelerator facility & corresponding scientific program

NICA /MPD /SPD – project provides good opportunity for the frontier experimental researches at JINR in the forthcoming decade

New laboratory - LHEP was founded (May 4, 2008) to concentrate efforts for realization of these plans

Conclusions IIConclusions II

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Last year we have celebrated the 90th Anniversary of the birth of

one of the Femtoscopy fathers Mikhail Isaakovich Podgoretsky

(22.04.1919-19.04.1995)

This year, it is just 20 years from his first visit in Nantes,

participating at CORINNE’90 and in fact stimulating

our GDRE collaboration

R. Lednicky 35

April 2, 2008 A.N.Sissakian, A.S.Sorin 35

Thank you for attention!

Welcome to the

collaboration!

Spare Slides

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37

Cassing – Bratkovskaya:

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

0.73c 0.91c

Rz2 2 (T/mt)

Rx2= x’2-

2vxx’t’+vx2t’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

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