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Physics of NICA

Physics of NICA. Vadim Kolesnikov. VBLHEP, JINR, Dubna. USTC-JINR Meeting, June 7-8, 2010. 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

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Physics of NICA

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  1. Physics of NICA Vadim Kolesnikov VBLHEP, JINR,Dubna USTC-JINR Meeting, June 7-8, 2010

  2. 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 V.I. Kolesnikov

  3. Nuclotron-based Ion Collider fAcility • Lab. Of High Energy Physics (JINR) • Accelerator complex • p(h),d(h),He,…Kr,..Au, E/A=4.5 GeV • Particle physics • Heavy-Ion physics • Spin physics • Applied research • Medicine • 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

  4. Quark-Gluon-Plasma ? Heavy-ion collisions‚Big Bang‘ in the Laboratory Initial State Hadronization time Au Au hadron degrees of freedom hadron degrees of freedom quarks and gluons • Fundamental properties of theory (QCD) • Universe (“Big Bang”) and astophysics (neutron stars) V.I. Kolesnikov

  5. Qurk-Gluon Plasma in LQCD • Latice QCD (LQCD): • Strong increase of the energy density e at critical temperature TC ~170 MeV • Phase transition from hadronic matter to partonic degrees of freedom (quarks, gluons) at energy density eC~1 GeV/fm3 Z. Fodor et al., Phys. Lett. B 568 (2003) 73 14 12 10 8 4 /T e Lattice QCD: 6 m =0 B 4 m =530 MeV B 2 Tc= 170 MeV 0 0.5 1.0 1.5 2.0 2.5 3.0 T/T c Critical conditions can be reached in head-on heavy-ion collisions at energies E/A > 5 GeV V.I. Kolesnikov

  6. The most intriguing and unexplored region • of 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 Phase diagram properties (Lattice QCD): - 1st order phase transition (HGQGP) small T, mB>0 - 2nd order (mq=0) or crossover (mq>0) at mB~0 - Critical End Point (CEP) in-between Challenge: comprehensive experimental program requires scan over the QCD phase diagram by varying collision parameters : system size, beam energyand collision centrality V.I. Kolesnikov

  7. QCD Critical End Point (CEP) • Does CEP exist in Nature? • Where is it in the (T-mB)-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 mB~400 MeV, sNN ~ 7 GeV NICA Experimental search for CEP via detailed scan of the QCD Phase diagram over the critical region with HI collisions! V.I. Kolesnikov

  8. Signals of the phase transition and CEP in A+A: • Non-monotonic energy dependence in strangeness production • Enhancement of multi-strange particles • Centrality dependence of charm suppression • Anisotropy in athimuthal distribution of product • (collective flow pattern) • Thermal dileptons and photons • High pT suppression of hadrons • Nonstatistical event by event fluctuations and correlations • Antibaryon production • ... V.I. Kolesnikov

  9. Relativistic Heavy-Ion (HI) Collisions (state of art) and prospects for NICA V.I. Kolesnikov

  10. Relativistic Heavy Ion Collisions (1) Evidence for deconfinement at SPS energies! NA50:anomalous J/y suppression in central A+A 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 T QGP Quarkonium suppression by color screening Mixed phase HG e V.I. Kolesnikov

  11. Relativistic Heavy Ion Collisions (2) Strong high pT suppression in hadron production  highly opaque matter for colored probes (not for photons) Constituent quark number scaling of elliptic flow  partonic collectivity in a relativistic quantum liquid sQGP matter at RHIC! V.I. Kolesnikov

  12. Motivation for the next generation of HI experiments 3nd generation experiment with dedicated detectors are required for more sensitive and detailed study Requirements to the 3rd generation experiments: • Energy range which brackets onset of deconfinement (sNN = 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 V.I. Kolesnikov

  13. 2nd generation HI experiments STAR/PHENIX @ BNL/RHIC. Originally designed for higher energies (sNN > 20 GeV), low luminosity for LES program L<1026 cm-2s-1 for Au79+. NA61 @ CERN/SPS. Fixed target, non-uniform acceptance, few energies (10,20,30,40,80,160A GeV), poor nomenclature of beam species 3nd generation HI experiments CBM @ FAIR/SIS-100/300 Fixed target, E/A=10-40 GeV, high luminosity, but SIS-300 after 2018 MPD @ JINR/NICA.Collider, small enough energy steps in the range sNN = 4-11 GeV, a variety of colliding systems, L~1027 cm-2s-1 for Au79+ V.I. Kolesnikov

  14. NICA/MPD –competitive & complimentary to • running experiments • STARat RHIC (BNL) preparation for LES • NA61 at SPS • in preparation: • CBM at SIS-100/300 (GSI) V.I. Kolesnikov

  15. NICA complex Nuclotron E/A = 1..5.5 GeV Q=+79 Collider Beams – p,d(h)..197Au79+ Collision energy – 4-11 GeV No bunches – 2x17 Luminosity: 1027 cm-2s-1(Au79+), 1032 (ph) Interaction points – 2 (MPD and SPD detectors) Ion source+Linac 2.109 ions/pulse E/A = 6.2 MeV Q = +32 Booster 2.109 ions/bunch E/A = 608 MeV Q=+32, electron cooling The MultiPurpose Detector is proposed for study of hot and dense baryonic matter in collisions of heavy ions over mass range A=1-197 at a centre-of-mass energy √sNN = 4-11 GeV. MPD SPD V.I. Kolesnikov

  16. Round Table Discussions on NICA@JINR Round Table DiscussionI Searching for the mixed phase of strongly interacting matter at the JINR Nuclotron July 7 - 9, 2005http://theor.jinr.ru/meetings/2005/roundtable/ Round Table Discussion II Searching 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 III Searching for the mixed phase of strongly interacting QCD matter at the NICA: Physics at NICA JINR (Dubna), November 5 - 6, 2008 http://theor.jinr.ru/meetings/2008/roundtable/ Round Table Discussion IV Searching for the mixed phase of strongly interacting QCD matter at the NICA: Physics at NICA (White Paper)‏ JINR (Dubna), September 9 - 12, 2009 http://theor.jinr.ru/meetings/2009/roundtable/

  17. NICA/MPD Project (documents) http://nica.jinr.ru http://nica.jinr.ru Version 0.8 V.I. Kolesnikov

  18. Study of fundamental properties of QCD: Confinement, QCD vacuum, global symmetries V.I. Kolesnikov

  19. Physics tasks for MultiPurpose Detector .. To measure a large variety of signals systematically changing collision parameters (energy, centrality, system size). Reference data (i.e. p+p) will be taken in the same experimental conditions. List of observables: • bulk observables (hadrons): 4p 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 Point CSR – Chiral Symmetry Restoration EOS – Equation Of State NICA White Paper (http://nica.jinr.ru) Round Table materials (http://jinr.ru/theor/) V.I. Kolesnikov

  20. NICA Physics. Phase transition K/p-ratio 1st order phase transition? Co-existence of partonic and hadronic degrees of freedom (mixed phase)? • Establish the onset of the observed signatures • Requirements: • energy scan • system size scan • total reconstruction of entropy & strangeness • (K+-,K0,L,p+-,p0) V.I. Kolesnikov

  21. NICA Physics. Strangeness 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 RHIC top SPS • 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? V.I. Kolesnikov

  22. NICA physics. Hadron properties • 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-) PLB 666 (2008) 425 • Strong enhancement of low-mass e+e- pairsin A+A • No enhancement in p+p nor in p+A • No measurement between s ~ 3-8 GeV yet! V.I. Kolesnikov

  23. Dileptons in Heavy Ion Collisions NICA – Round Table IVJINR, Dubna, September 9-12, 2009 5.1 Low-mass dileptons at NICA I. 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. • NICA’s energy range very well suited to fill an important niche: • unveil the onset of the low-mass pair enhancement. • Systematic studies of pA colliisions • Study pair enhancement under highest baryon density conditions V.I. Kolesnikov

  24. NICA Physics. Electromagnetic probes (dileptons) (Predictions, HSD model) Elena Bratkovskaya at RoundTable workshop NICA collider fixed target • NICA’s energy range very well suited to fill an important niche: • Unveil the onset of the low-mass pair enhancement. • Systematic studies of pA collisions • Study pair enhancement under highest baryon density conditions V.I. Kolesnikov

  25. Collective flow (intro) y py px x y z x Initial eccentricity of the overlap zone leads to the final-state momentum azimuthal asymmetry Reaction plane: z-x plane beam UrQMD impact parameter Flow pattern connected to the initial pressure gradients Fourier expansion of azimuthal distribution of emitted particles with respect to the reaction plane: Directed flow (in-plane collective motion) probe of the initial reaction stage, sensitive to EOS Elliptic flow probes the expanding stage of the fireball evolution V.I. Kolesnikov

  26. Flow. Prospects for NICA • v2 disappearence at y=0 for protons predicted for a 1st order phase transition • No convincing data yet, large systematic errors in method(s) Nucl. Phys.A 750 (2005) Collapse of the direct flow of protons @ E/A=30 GeV (1st order transition?). Has to be verified! V.I. Kolesnikov

  27. HBT correlation studies @ NICA Correlation analysis plays a crucial role in the study of space-time aspects of the system created in HI collisions S(P,r’) ~ f(Rside,Rout,Rlong) – source function P = p1+p2, q=(p’1+p’2)/2 NICA What the HBT data tell us: • Little change of Rout (emission duration) • and Rside (fireball radius) • Slow rise of RLong (lifetime) • No indication of Rout>>Rside • (1st order phase transition) • Small partonic phase fraction? • Standard technique does not work • properly for a 2-component source? V.I. Kolesnikov

  28. HBT correlation studies @ NICA (2) Requirements: • (data) high statistic, uniform acceptance, excellent PID • (theory) multidimensional fit technique MPD CDR v0.8 Vast nomenclature of pair species V.I. Kolesnikov

  29. NICA physics. CEP (experimental signatures) K/p-ratio: event-by-event dynamical fluctuations Better precision than fixed target experiments provide! (factor of ~3 compared to existing data) NICA • Challenge: • large acceptance (close to 4p, total f-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 V.I. Kolesnikov

  30. CEP. Experimental signature (antibaryons) • Critical point serves an attractor for the hydrodynamic trajectories • This leads to different behavior of mB/T over a trajectory in the vicinity of CEP • and manifests itself in a modification of the anti-p/p ratio (~mB/T) for such trajectories Asakawa et al. PRL 101, 122302 (2008) 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 Effect of the order of mB/T  then anti-d/d are more sensitive (~ 2 mB/T)? V.I. Kolesnikov

  31. CEP. Experimental signature (antideuterons) • anti-p/p ~ 2.10-3 at NICA • `d/d ~ (`p/p)2 • gaussian in rapidity (s ~ 1) We expect • ~ 3000 anti-d per week @ NICA (overall eff. ~ 50%)  feasible! Study of critical phenomena with antiprotons and antideuterons @ NICA V.I. Kolesnikov

  32. A+A collisions. Antihyperon to antibaryon ratio Antibaryon production in the high baryon density regime  sensitive probe of collisions dynamics • Unusual behavior of `L /`p ratio at low energies • Large experimental errors • No satisfactory theoretical description of antibaryon production in A+A UrQMD model Phys. Rev. C73, 044910 (2006) NICA: detailed study of antibaryon production and annihilation mechanismsin dense nuclear matter.

  33. 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 (p,g) 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 L,p,p,K0 V.I. Kolesnikov

  34. The Apparatus: basic requirements • Physics Observables • Deconfinementparticle yields (g,p,K,p,L,X,W, fragments), flow • Critical pointfluctuations & correlations of identified particles • Chiral phase transitiondilepton (e+e-) • Detector requirements: • Large homogenous acceptance : 2p in athimuth, |h|<3, 0.1<pt<2.5 GeV/c • High efficient 3-D track reconstruction • PID: p/K up to 1.5 GeV/c, K/p up to 2.5 GeV/c • ECAL for g, 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 V.I. Kolesnikov

  35. Au+Au collisions @ NICA/MPD (feasibility study) V.I. Kolesnikov

  36. MPD simulation & reconstruction chain • Branches for all the MPD subdetectors • A variety of event generator options • Detector response simulation + reconstruction tasks V.I. Kolesnikov

  37. Au+Au collisions: yields & spectra • Au+Au collisions sNN = 4-11 GeV (RQMD) • Event rate (design luminosity, st=6.8 barn)~7 kHz • charged dn/dy ~ 500 at midrapidity • <pt> ~ 600 MeV/c (K+, |h|<1.0) • (Eg )max < 2 GeV, Ng ~ 600 Eg < 2 GeV, Ng < 600 • moderate occupancy • low <pt>  transparent detector • PID up to 2.5 GeV/c V.I. Kolesnikov

  38. Au+Au collisions: multiplicities All species will be measured at NICA V.I. Kolesnikov

  39. Observables. Identified hadrons (spectra, yields) • Starting point for ALL other studies! • Collisions dynamics, particle production mechanism • Space-time evolution of the source • Source thermodynamics (T), radial flow (b) • Total yields, ratios  phase diagram mapping (T, mB from statistical model fits) • At NICA energies 4p 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 4p (essential for baryons!) MPD/NICA More about hadron PID inSlava’s talk V.I. Kolesnikov

  40. MPD. Hyperon reconstruction Au+Au @ 9A GeV Good capability for hyperon measurements V.I. Kolesnikov

  41. HBT correlation studies @ NICA (MPD CDR v0.8) Standard fits do they job. Time for much more advanced algorithms to come!

  42. Dileptons. e+e- hadron cocktail QGSM model, K. Gudima et al. data Main experimental challenge: large combinatorial background. Powerful PID (hadron suppression up 104) and good mass resolution (~2%) required. V.I. Kolesnikov

  43. 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 V.I. Kolesnikov

  44. Spin Physics at NICA V.I. Kolesnikov

  45. Spin physics @ NICA. Protons’s spin 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): quark contribution gluon contribution Lq, Lg – angular orbital momentum contributions (unknown) Dg is less then speculated  missing spin contribution (“spin crysis”) New (precise) measurements of many PDFs (Parton Distribution Functions) required V.I. Kolesnikov

  46. Spin physics @ NICA (2) • NICA advantages: • Beams – p,d(h), L ~ 1032 cm-2s-1 • Polarization – transversal and longitudinal (p > 50%) • Collision energy – up to √s = 25GeV • Spin physics program with polarized beams at NICA: • Comprehensive studies of DY and J/Y production processes (polarized and unpolarized) • Spin effects in one and two hadron production processes • Spectroscopy of quarkonia and diffractive processes V.I. Kolesnikov

  47. Spin physics @ NICA (3) V.I. Kolesnikov

  48. Spin physics @ NICA: polarized DY V.I. Kolesnikov

  49. 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 • Promising spin physics at NICA • Much more promising – closer collaboration among many • active participants in LES programs (GSI/JINR/BNL/USTC) V.I. Kolesnikov

  50. Thank you for your attention!

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