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Physics of NICA

Vadim Kolesnikov

VBLHEP, JINR, Dubna

USTC-JINR Meeting, June 7-8, 2010

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Content

Heavy Ion (HI) collisions – study of fundamental properties of QCD matter

Scan of the QCD phase diagram with NICA

Deconfinement phase transition, search for the Critical End Point (CEP), modification of hadron properties in dense matter – prospects for NICA

Simulation of A+A at NICA energies (feasibility studies)

Spin physics at NICA

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New flagship project at JINR, Dubna, Russia Based on the technological development

of the Nuclotron facility Optimal usage of the existing infrastructure Modern machine which incorporates new

technological concepts gain in luminosity First beams expected in 2015

Nuclotron-based Ion Collider fAcility Lab. Of High Energy Physics (JINR)

• Accelerator complex p(),d(),He,…Kr,..Au, E/A=4.5 GeV• Particle physics• Heavy-Ion physics • Spin physics• Applied research• Medicine

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Heavy-ion collisions‚Big Bang‘ in the Laboratory

time

Initial State Hadronization

Au Au

Quark-Gluon-Plasma ?

quarks and gluons hadron degrees

of freedom

hadron degrees

of freedom

Fundamental properties of theory (QCD) Universe (“Big Bang”) and astophysics (neutron stars)

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Qurk-Gluon Plasma in LQCDQurk-Gluon Plasma in LQCD

TTcc = 170 MeV= 170 MeV

Latice QCD (LQCD):Latice QCD (LQCD):

Strong increase of the energyStrong increase of the energy density density at critical temperature at critical temperature TTC C ~170 MeV~170 MeV

Phase transition from hadronicPhase transition from hadronic matter to partonic degrees ofmatter to partonic degrees of freedom (quarks, gluons)freedom (quarks, gluons) at energy density at energy density CC~1 GeV/fm~1 GeV/fm3 3

Critical conditions can be reached in head-on heavy-ionCritical conditions can be reached in head-on heavy-ion collisions at energies E/A > 5 GeVcollisions at energies E/A > 5 GeV

0.5 1.0 1.5 2.0 2.5 3.00

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Z. Fodor et al., Phys. Lett. B 568 (2003) 73

Lattice QCD: B=0 B=530 MeV

T/Tc

/T

4

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The most intriguing and unexplored regionof the QCD phase diagram:

characterized by the highest net baryon density

detailed information about properties of the phase transition region can be deduced

strong discovery potential: a) Critical End Point b) Chiral Symmetry Restoration

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 energy andcollision centrality

Phase diagram properties (Lattice QCD): - 1st order phase transition (HGQGP) small T, B>0 - 2nd order (mq=0) or crossover (mq>0) at B~0 - Critical End Point (CEP) in-between

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QCD QCD CCritical ritical EEnd nd PPoint (oint (CEPCEP))

Does CEP exist in Nature? Where is it in the (T-B)-plane?

LQCD calculations at finite baryon density are not perfect and position of the CEP is fairly uncertain! Important ingredients are: - quark masses - lattice discretization (computation cost)

Number of methods (groups) predict CEP at B~400 MeV, ssNNNN ~ 7 GeV

NICA

Experimental search for CEP via detailed scan of the QCDPhase diagram over the critical region with HI collisions!

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• Non-monotonic energy dependence in strangeness productionNon-monotonic energy dependence in strangeness production

• Enhancement of multi-strange particles Enhancement of multi-strange particles

• Centrality dependence of charm suppression Centrality dependence of charm suppression

• Anisotropy in athimuthal distribution of product Anisotropy in athimuthal distribution of product (collective flow pattern)(collective flow pattern)

• Thermal dileptons and photonsThermal dileptons and photons

• High pHigh pTT suppression of hadrons suppression of hadrons

• Nonstatistical event by event fluctuations and correlationsNonstatistical event by event fluctuations and correlations

• Antibaryon productionAntibaryon production

• ......

Signals of the phase transition and CEP in A+A:Signals of the phase transition and CEP in A+A:

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Relativistic Heavy-Ion (HI) Collisions

(state of art)

and

prospects for NICA

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Relativistic Heavy Ion Collisions (1)

Evidence for deconfinement at SPS energies!

NA49: anomalies in hadron production:

“Horn” – sharp maximum in the strangeness-to-entropy ratio in the transition region

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

NA50: anomalousJ/suppression in central A+A

HG

Mixedphase

QGP

T

Quarkoniumsuppression bycolor screening

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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!

Relativistic Heavy Ion Collisions (2)

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Motivation for the next generation of HI experiments

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

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Requirements to the 3rd generation experiments:

Energy range which brackets onset of deconfinement (ssNNNN = 3-11 = 3-11 GeV)

High luminosity small enough energy steps, sufficient statistic

Vast nomenclature of projectile nuclei (from p to Au)

Large uniform acceptance and PID

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CBM @ FAIR/SIS-100/300Fixed target, E/A=10-40 GeV, high luminosity,but SIS-300 after 2018

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

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 enoughenergy steps in the range ssNNNN = 4-11 GeV,a variety of colliding systems, L~1027 cm-2s-1 for Au79+

2nd generation HI experiments

3nd generation HI experiments

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NICA/MPD –competitive & complimentary to

running experiments

- STAR at RHIC (BNL) preparation for LES- NA61 at SPS

in preparation:

- CBM at SIS-100/300 (GSI)

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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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Round Table Discussions on NICA@JINRRound Table Discussion ISearching for the mixed phase of strongly interacting matter at the JINR Nuclotron July 7 - 9, 2005 http://theor.jinr.ru/meetings/2005/roundtable/

Round Table Discussion IISearching for the mixed phase of strongly interacting matter at the JINR Nuclotron: Nuclotron facility development JINR, Dubna, October 6 - 7, 2006 http://theor.jinr.ru/meetings/2006/roundtable/

Round Table Discussion IIISearching for the mixed phase of strongly interacting QCD matter at the NICA: Physics at NICAJINR (Dubna), November 5 - 6, 2008http://theor.jinr.ru/meetings/2008/roundtable/

Round Table Discussion IVSearching for the mixed phase of strongly interacting QCD matter at the NICA: Physics at NICA (White Paper)JINR (Dubna), September 9 - 12, 2009http://theor.jinr.ru/meetings/2009/roundtable/

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http://nica.jinr.ruVersion 0.8

http://nica.jinr.ru

NICA/MPD Project (documents)

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Study of fundamental properties of QCD: Confinement, QCD vacuum, global symmetries

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Physics tasks for MultiPurpose Detector

bulk observables (hadrons): 4 particle yields (OD, EOS) event-by-event fluctuation in hadron productions (CEP) HBT 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)OD – Onset of Deconfinement

CEP – Critical End PointCSR – Chiral Symmetry RestorationEOS – Equation Of State

.. To measure a large variety of signals systematically changing collisionparameters (energy, centrality, system size). Reference data (i.e. p+p) willbe taken in the same experimental conditions.

List of observables:

NICA White Paper (http://nica.jinr.ru)Round Table materials (http://jinr.ru/theor/)

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NICA Physics. Phase transition

Establish the onset of the observed signaturesEstablish the onset of the observed signatures Requirements:Requirements:• energy scanenergy scan• system size scansystem size scan• total reconstruction of entropy & strangenesstotal reconstruction of entropy & strangeness (K(K+-+-,K,K00,,,,+-+-,,00))

1st order phase transition?

Co-existence of partonicand hadronic degrees offreedom (mixed phase)?

K/-ratio

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Increased production rate of (anti)strange quarks in deconfinement matter Enhancement increases with the content of strange quarks Similar pattern from the (top) SPS to RHIC energies

NICA Physics. Strangeness

top SPS

RHIC

The strangeness enhancement pattern can be accounted for by a core (thermalized hadron resonance gas) + corona (superposition of N-N collisions) effect.

Where is the onset of the effect of fully equilibrated gas production? Is this effect explain the hadron production at NICA?

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Modification of hadron properties in baryon environment due to: - many-body interactions with the surrounding - In-medium modification of the QCD condensate (Chiral symmetry restoration)

Dileptons from vector meson decays are the best probes (,, e+e-)

NICA physics. Hadron propertiesNICA physics. Hadron properties

PLB 666 (2008) 425

Strong enhancement of low-mass e+e- pairs in A+A No enhancement in p+p nor in p+A No measurement between ss ~ 3-8 GeV yet!

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NICA’s energy range very well suited to fill an important niche:NICA’s energy range very well suited to fill an important niche: unveil the onset of the low-mass pair enhancement.unveil the onset of the low-mass pair enhancement. Systematic studies of pA colliisionsSystematic studies of pA colliisions Study pair enhancement under highest baryon density conditionsStudy pair enhancement under highest baryon density conditions

Dileptons in Heavy Ion CollisionsDileptons in Heavy Ion Collisions

NICA – Round Table IVNICA – Round Table IVJINR, Dubna, September 9-12, 2009JINR, Dubna, September 9-12, 2009

5.1 Low-mass dileptons at NICAI. Tserruya

(White paper) The NICA facility is thus ideally suited to search not only for the QCD critical point but also for the

onset of the low-mass dilepton enhancement. In the energy range covered by NICA, the mid rapidity baryon density is expected to reach a maximum

and thus the NICA facility will allow to measure low-mass dileptons under optimal conditions. Our present knowledge of the QCD phase diagram shows a critical end point at a baryon chemical

potential of about μB = 400 MeV with a smooth cross over at lower values and a first order phase transition at larger values. Again NICA’s planned energy range is ideally suited to explore this region.

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NICA Physics. Electromagnetic probes (dileptons)

NICA’s energy range very well suited to fill an important niche:NICA’s energy range very well suited to fill an important niche: Unveil the onset of the low-mass pair enhancement.Unveil the onset of the low-mass pair enhancement. Systematic studies of pA collisionsSystematic studies of pA collisions Study pair enhancement under highest baryon density conditionsStudy pair enhancement under highest baryon density conditions

(Predictions, HSD model)

Elena Bratkovskaya at RoundTable workshop

colliderfixed target N

ICA

NIC

A

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xz

y

p

x

p

y

y

x

Reaction plane: z-x plane

impact parameter be

am

Initial eccentricity of theoverlap zone leads to thefinal-state momentumazimuthal asymmetry

Fourier expansion of azimuthal distribution ofemitted particles with respect to the reaction plane:

Collective flow (intro)

Directed flow (in-plane collective motion)probe of the initial reaction stage,sensitive to EOS

Elliptic flow probes the expandingstage of the fireball evolution

Flow pattern connected tothe initial pressure gradients

UrQMD

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Flow. Prospects for NICA

Collapse of the direct flow of protons @ E/A=30 GeV (1st order transition?). Has to be verified!

Nucl. Phys.A 750 (2005)

v2 disappearence at y=0 for protons predicted for a 1st order phase transition No convincing data yet, large systematic errors in method(s)

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HBT correlation studies @ NICACorrelation analysis plays a crucial role in the study ofspace-time aspects of the system created in HI collisions

NICAS(P,r’) ~ f(Rside,Rout,Rlong) – source function P = p1+p2, q=(p’1+p’2)/2

Little change of Rout (emission duration) and Rside (fireball radius)

Slow rise of RLong (lifetime) No indication of Rout>>Rside

(1st order phase transition)

What the HBT data tell us:

Small partonic phase fraction? Standard technique does not work

properly for a 2-component source?

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HBT correlation studies @ NICA (2)

Vast nomenclature of pair species

Requirements:(data) high statistic, uniform acceptance, excellent PID(theory) multidimensional fit technique

MPD CDR v0.8

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NICA physics. CEP (experimental signatures)NICA physics. CEP (experimental signatures)

Challenge: large acceptance (close to 4, total-coverage) excellent tracking and PID suppression of fluctuation signals due to: - Final State Interactions (FIS) that washed out the signal - critical slowing down for system passing the critical region

K/-ratio: event-by-event dynamical fluctuations

Better precision than fixedtarget experiments provide!(factor of ~3 comparedto existing data)

NICA

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Asakawa et al. PRL 101, 122302 (2008)

CEP. Experimental signature (antibaryons) Critical point serves an attractor for the hydrodynamic trajectoriesThis leads to different behavior of B/T over a trajectory in the vicinity of CEP and manifests itself in a modification of the anti-p/p ratio (~B/T) for such trajectories

Effect of the order of B/T then anti-d/d are more sensitive (~ 2 B/T)?

Tc

freeze-out

System evolves from Tc to freeze-out Fast particles emitted earlier High pt (pt>0.5 GeV/c) anti-p suppression for CEP

• FO, CO

• QCP

BT

BT

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CEP. Experimental signature (antideuterons)

anti-p/p ~ 2.10-3 at NICA

d/dp/p gaussian in rapidity ( ~ 1) We expect ~ 3000 anti-d per week @ NICA (overall eff. ~ 50%) feasible!

Study of critical phenomena with antiprotons and antideuterons @ NICA

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Antibaryon production in the high baryon density regime sensitive probe of collisions dynamics

Unusual behavior of p ratio at low energies Large experimental errors

No satisfactory theoretical description of antibaryon production in A+A

A+A collisions. Antihyperon to antibaryon ratio

Phys. Rev. C73, 044910 (2006)

UrQMD model

NICA: detailed study of antibaryon production andannihilation mechanisms in dense nuclear matter.

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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 emission time (HBT)

Strangeness and resonance production

Exotic strange multibaryon states with ,p,,K0

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The Apparatus: basic requirements

Physics Observables Deconfinement particle yields (,K,p, fragments), flow Critical point fluctuations & correlations of identified particles Chiral phase transition dilepton (e+e-)

Detector requirements: Large homogenous acceptance : 2 in athimuth, ||<3, 0.1<pt<2.5 GeV/c High efficient 3-D track reconstruction PID: /K up to 1.5 GeV/c, K/p up to 2.5 GeV/c ECAL for e Vertexing with PID at pt < 0.15 GeV/c, two track resolution ≤ 1 cm Event characterization: impact parameter & event plane reconstruction Event rate capability up to ~ 7 kHz

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Au+Au collisions @ NICA/MPD (feasibility study)

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MPD simulation & reconstruction chain

Branches for all the MPD subdetectors A variety of event generator options Detector response simulation + reconstruction tasks

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Au+Au collisions Au+Au collisions ssNN NN = 4-11 GeV (RQMD)= 4-11 GeV (RQMD)

Event rate (design luminosity, Event rate (design luminosity, tt=6.8 barn)~7 kHz=6.8 barn)~7 kHz

charged dn/dy ~ 500 at midrapiditycharged dn/dy ~ 500 at midrapidity <p<ptt> ~ 600 MeV/c (K> ~ 600 MeV/c (K++, |, ||<1.0)|<1.0)

(E(E ) )maxmax < 2 GeV, N < 2 GeV, N ~ 600 ~ 600

Au+Au collisions: yields & spectra

E < 2 GeV, N < 600

moderate occupancy low <pt> transparent detector PID up to 2.5 GeV/c

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Au+Au collisions: multiplicities

All species will be measured at NICA

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Observables. Identified hadrons (spectra, yields)

At NICA energies 4 yields are required (rapidity distribution compared to the width of single fireball’s), Due to incomplete pt-coverage the extrapolated yields can have large systematic errors Detector acceptance close to 4 (essential for baryons!)

Starting point for ALL other studies! Collisions dynamics, particle production mechanism Space-time evolution of the source Source thermodynamics (T), radial flow () Total yields, ratios phase diagram mapping (T, B from statistical model fits)

MPD/NICA

More about hadron PID inSlava’s talk

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MPD. Hyperon reconstruction

Au+Au @ 9A GeV

Good capability for hyperon measurements

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HBT correlation studies @ NICA(MPD CDR v0.8)

Standard fits do they job. Time for much more advanced algorithms to come!

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Dileptons. e+e- hadron cocktail

QGSM model, K. Gudima et al.

Main experimental challenge: large combinatorial background.Powerful PID (hadron suppression up 104) and good mass resolution (~2%) required.

data

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Electromagnetic probes (photons) – ideal probes of the fireball interior (not affected by strongly interacting matter)

Photon distributions are results of convolution of emissions from overall fireball history Different processes – different characteristic spectra Reconstruct spectra not a problem Deconvolution is a challenge detailed microscopic calculations + models for evolution

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Spin Physics at NICA

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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 crysis”)

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

Lq, Lg – angular orbital momentum contributions (unknown)

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NICA advantages:

Beams – p,d(), L ~ 1032 cm-2s-1 Polarization – transversal and longitudinal (p > 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

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Spin physics @ NICA (3)

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Spin physics @ NICA: polarized DY

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Conclusion & Outlook

NICA/MPD project – new heavy-ion program at JINR, Dubna aimed at comprehensive study of the QCD phase diagram

NICA HI physics program requires a multipurpose detector with extreme performances in:

• hermeticity towards 4 geometry• tracking and PID• robust event selection algorithms

Much more promising – closer collaboration among many active participants in LES programs (GSI/JINR/BNL/USTC)

Promising spin physics at NICA

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Thank youThank you

for your attention!for your attention!

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Extra slides

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QCD phase diagram properties (Lattice QCD): 1st order phase transition (HGQGP) small T, B>0 2nd order (mq=0) or crossover (mq>0) at B~0 Critical End Point (CEP) in-between

Properties of the phase diagram of matter

WaterQCD matter

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• Early stage conditions, partonic dynamics, energy and baryon transportEarly stage conditions, partonic dynamics, energy and baryon transport net baryons, flownet baryons, flow

• Thermodynamic properties, test for equilibrium, (T-Thermodynamic properties, test for equilibrium, (T-BB)-mapping)-mapping

inclusive hadron spectra, multiplicities and particle ratiosinclusive hadron spectra, multiplicities and particle ratios

• EOS, transverse and longitudinal expansion, collective phenomena,EOS, transverse and longitudinal expansion, collective phenomena, space-time evolutionspace-time evolution spectra, HBT, cluster yields and coalescencespectra, HBT, cluster yields and coalescence

• Signals for phase transitionSignals for phase transition strangeness-to-entropy (K/strangeness-to-entropy (K/) ratio, slopes) ratio, slopes

• Critical phenomena during nuclear matter evolutionCritical phenomena during nuclear matter evolution particle ratio and net-baryon number fluctuationsparticle ratio and net-baryon number fluctuations

• Related topics (event characterization) centrality and event plane determination with hadron multiplicity

Hadron spectraStudy of fundamental properties of the Hot QCD MatterStudy of fundamental properties of the Hot QCD Matter ((objectivesobjectives//observablesobservables))

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PID methods in MPD (hadrons+e)

PID method: Time Of FlightPID separation : e/h – 0.1..0.35 GeV/c /K – 0.1..1.5 GeV/c K/p – 0.1..2.5 GeV/cChallenge: overall resolution < 100 ps, good start detector

PID method: Ionization loss (dE/dx)PID separation: e/h – 1.3..3 GeV/c /K – 0.1..0.6 GeV/c K/p – 0.1..1.2 GeV/cChallenge: resolution better than 8%, combined PID for the crossover regions

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Spin physics @ NICA: DY

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CEP (experimental signatures)CEP (experimental signatures)

Large event-by-event fluctuations are expectedwhen the system hadronizes close to thepredicted QCD Critical End Point

Observables: fluctuation pattern ofexperimental observables sensitiveto the proximity of the CEP : <pt> multiplicity azimuthal distributions particle ratios (K/) net-baryon number

NICA

………….………….………….

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Au

Au

- “spectator”

- “participant”

b

Non-central HI collisions

Collision “centrality” (impact parameter b or % of tot)has been determined by measuring spectatorsin a Zero Degree Calorimeter (ZDC)

Collective flow Dynamics of fireball evolution, Equation Of State (EOS) Signal of phase transition