Joint Institute for Nuclear Research Joint Institute for Nuclear Research International Intergovernmental Organization Nuclotron-based Ion Collider fAcility (NICA) at JINR: New Prospect for Heavy Ion Collisions Genis Musulmanbekov, JINR, Dubna For NICA Collaboration

Contents Heavy Ion Collisions (HIC): Motivations NICA Facility at Dubna Goals of NICA/MPD Project Physics and Observables in HIC MultiPurpose Detector (MPD)

Heavy Ion Collisions ~ 20 years GSI E Lab = 1 – 2 AGeV Dubna E Lab = 1 – 6 AGeV BNL – AGS E Lab = 20 – 158 AGeV CERN – SPS E Lab = 20 – 158 AGeV BNL – RHIC √s =20 – 200 GeV

New Phenomena in HIC Stopping power Collective flows Enhanced yield of multi(strange) baryons Enhanced and nonmonotonic (vs. beam energy) yield of K+ mesons. Broadening of transverse momentum distribution of kaons Broadening of dilepton decay width of rho –mesons. Jet quenching, J/Psi suppression and others

Hadron gas Mixed Phase QGM Pre-equilibrium Initial nuclei Freezout Time Space

NICA T NBNB RHIC,SPS,NICA,FAIR Mixed phase

Nuclear and Energy Density in central Au+Au collisions

FAIR and NICA  s =9 GeV  s =9 GeV Maximal baryonic densities on freeze-out curve!  High densities on interaction stage!? J.Cleymans, J.Randrup, 2006 High baryonic densities

Experimental programs FacilitySPSRHICNICASIS-300 DetectorNA61STARPHENIXMPDCBM Start (year) Energy (for Pb-ions) c.m. GeV ≤ 11 ≤ 8.5 PhysicsCP,ODCP,ODCP,OD,HDMCMECP,OD,HDM CP – critical endpoint OD – onset of deconfinement HDM – hadronic dense matter

NICA Facility

The main goal of the NICA project is an experimental study of hot and dense nuclear matter and spin physics These goals are proposed to be reached by These goals are proposed to be reached by : development of the existing accelerator facility (1st stage of the NICA accelerator programme: Nuclotron-M subproject) as a basis for generation of intense beams over atomic mass range from protons to uranium and light polarized ions; design and construction of heavy ion collider with maximum collision energy of  s NN = 11 GeV and average luminosity cm -2 s -1 (for U 92+ ), and polarized proton beams with energy  s ~ 25 GeV and average luminosity > cm -2 s -1 ;

Scheme of the NICA compex Booster (30 Tm) 2(3?) single-turn injections, storage of 3.2×10 9, acceleration up to 50 MeV/u, electron cooling, acceleration up to 400 MeV/u Nuclotron (45 Tm) injection of one bunch of 1.1×10 9 ions, acceleration up to 3.5 GeV/u max. Collider (45 Tm) Storage of 15 bunches  1  10 9 ions per ring at 3.5 GeV/u, electron and/or stochastic cooling Injector: 2×10 9 ions/pulse of 238 U 32+ at energy 6 MeV/u IP-1 IP-2 Stripping (40%) 238 U 32+  238 U 92+ Two superconducting collider rings 2х15 injection cycles

NICA parametersCircumferencem225 Number of collision points 2 Beta function in the collision point m0.5 Rms momentum spread Rms bunch length m0.3 Number of ions in the bunch 10 9 Number of bunches 15 Incoherent tune shift 0.05 Rms beam emittance at 1 GeV/u / at 3.5 GeV/u  mm mrad 3.8 / 0.26 Luminosity per one interaction point at 1 GeV/u at 3.5 GeV/u cm -2 s   Circumference, m  *, m  p/p (one  ) 1  Bunch length (  ), m Beam emittance (  ),  mm  mrad Bunch intensity (1- 2)  Bunch number per ring 15 8.Average luminosity forUU at 3.5 GeV/u for pp at 12.5 GeV 1.1  cm -2  s -1 3  cm -2  s -1 3  cm -2  s -1

Stage 1: years 2007 – Upgrate and Development of the Nuclotron facility - Preparation of Technical Design Report of the NICA and MPD - Start prototyping of the MPD and NICA elements Stage 2: years 2008 – Design and Construction of NICA and MPD Stage 3: years 2010 – Assembling Stage 4: year Commissioning The NICA Project Milestones

NICA provides unique possibility for the heavy ion physics program: 1. Heavy ion beams in wide energy range: 2. Possibility to perform atomic mass and centrality scan 3. Few intersection points for detectors with large energy-independent acceptance ~ 4. High luminosity L ~ см -2 с -1 √s = 4 – 11 GeV

NICA/MPD physics program Search for in-medium properties of hadrons in a dense and hot baryonic matter; Nuclear matter equation of state, possible signs of deconfinement chiral symmetry restoration phase transitions and QCD critical endpoint

Experimental observables: Scanning in beam energy and centrality of excitation functions for Multiplicity and global characteristics of identified hadrons including multi-strange particles Fluctuations in multiplicity and transverse momenta Directed and elliptic flows for various indentified hadrons Particle correlations Dileptons and photons Polarization effects in heavy ion collisions (polarization of strange baryons, azimuthal asymmetries)

♣ What to measure Multistrange hyperons. The yields, spectra and collective flows of (multi) strange hyperons are expected to provide information on the early and dense phase of the collision. Event-by-event fluctuations. The hadron yields and their momenta should be analyzed event-wise in order to search for nonstatistical fluctuations which are predicted to occur in the vicinity of the critical endpoint. HBT correlations. Measurement of short range correlations between hadrons π, K, p, Λ allows one to estimate the space-time size of a system formed in nucleus-nucleus interactions. Penetrating probes. Measurements of dilepton pairs permit to investigate the in-medium spectral functions of low-mass vector mesons which are expected to be modified due to effects of chiral symmetry restoration in dense and hot matter.. Polarization effects. Measurement of (multi)strange baryon polarization, asymmetries, Azimuthal charge asymmetry (CME).

Current Experimental and Theoretical Status of Heavy Ion Collision Investigations

Strange-to-nonstrange ratios in central collisions. “Horn” Effect ( World Data)‏ Figure from arXiv:nucl-ex/ v1

Excitation functions of particle ratios Experimental data: E896, NA49, STAR, PHENIX, BRAHMS E.Bratkovskaya et al.,(2004) Transport models : HSD, UrQMD, GiBUU Exp. data (particularly a maximum at E~30 AGeV) are not well reproduced within the hadron-string picture => evidence for nonhadronic degrees of freedom

Excitation function of particle ratios Excitation function of particle ratios Munzinger: Simposium on Dense Baryonic Matter, GSI 2009 Thermal Model: rapid saturation of contributions from higher resonances in conjunction with additional pions from the sigma describes horn structure well.

Transverse mass spectra of Kaons Transport models: HSD 2.0 HSD 2.0 UrQMD 2.0 UrQMD 2.0 UrQMD 2.1 (effective heavy resonances with masses 2 < M < 3 GeV and isotropic decay) UrQMD 2.1 (effective heavy resonances with masses 2 < M < 3 GeV and isotropic decay) GiBUU GiBUU All transport models fail to reproduce the T- slope without introducing special „tricks“ which are, however, inconsistent with other observables! 3D-fluid hydrodynamical model gives the right slope! Is the matter a parton liquid?

Fluctuations of the quark number density (susceptibility) at μ_B >0 (C.Allton et al., 2003) Lattice QCD predictions : Fluctuations of the quark number density (susceptibility) at μ_B >0 (C.Allton et al., 2003) Fluctuations: theoretical status 0 χ q (quark number density fluctuations) will diverge at the critical end point Experimental observation: Baryon number fluctuations Baryon number fluctuations Charge number fluctuations Charge number fluctuations

Multiplicity Fluctuati Multiplicity Fluctuations Theoretical predictions: 3 – 10 times anhancement NA49 result: NA49 result: Measured scaled variances are close to the Poisson one – close to 1! No sign of increased fluctuations as expected for a freezeout near the critical point of strongly interacting matter was observed.

Multiplicity fluctuations  of charged particles as a function of the number of projectile participants N part proj : Multiplicity fluctuations  of charged particles as a function of the number of projectile participants N part proj : Multiplicity Fluctuati Multiplicity Fluctuations

Event-by-event dynamical fluctuations K/π ratio Event mixing for the statistical background estimation:

Event-by-event dynamical fluctuations Transverse Momentum Transverse Momentum Event mixing for the statistical background estimation: For the system of independently emitted particles fluctuation Ф p t goes to zero (no particle correlations)., where

Collective flow: general considerations Collective flow: general considerations v 2 = 7%, v 1 =0 v 2 = 7%, v 1 =-7% v 2 = -7%, v 1 =0 Out-of-plane In-plane Y X - directed flow - elliptic flow V 2 > 0 indicates in-plane emission of particles V 2 < 0 corresponds to a squeeze-out perpendicular to the reaction plane (out-of-plane emission) x z Non central Au+Au collisions : interaction between constituents leads to a pressure gradient => spatial asymmetry is converted to an asymmetry in momentum space => collective flow Y

Directed v 1 and elliptic v 2 flows Small wiggle in v 1 at midrapidity is not described by HSD and UrQMD Too large elliptic flow v 2 at midrapidity from HSD and UrQMD for all centralities ! Experiment (NA49): breakdown of elliptic v 2 flow at midrapidity ! Signature for a first order phase transition? H.Stoecker et al., 2005

Sergey Panitkin q out q side q long R side R long R out x1x1x1x1 x2x2x2x2 p1p1p1p1 p2p2p2p2  HBT: Quantum interference between identical particles C (q)‏ q (GeV/c)‏ 1 2 HBT interferometry Two-particle interferometry: p-space separation  space-time separation

In Search of the QGP. Expectations. “Energy density” One step further: Hydro calculation of Rischke & Gyulassy expects Rout/Rside ~ Kt = 350 MeV.

Excitation function of the HBT parameters ~10% Central AuAu(PbPb) events y ~ 0 k T 0.17 GeV/c no significant rise in spatio- temporal size of the  emitting source at RHIC Ro/Rs ~ 1 Some rise in Rlong Note ~100 GeV gap between SPS and RHIC Where are signs of phase transition?!

Model Comparison (the puzzle) Subset of models shown Broad range of physics scenarios explored Poor description of HBT data the puzzle

Dileptons Dileptons Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear dynamics !  Excitation function for dilepton yields Study of in-medium effects with dilepton experiments: Study of in-medium effects with dilepton experiments: DLS, SPS (CERES, HELIOS))

Broadening of dilepton decay spectra of light resonances arXiv:nucl-th/ v2arXiv:nucl-th/ v1

5. Dileptons 5. Dileptons Clear evidence for a broadening of the  spectral function! Clear evidence for a broadening of the  spectral function!  and  show clear peaks on an approx. exponential background in mass!  and  show clear peaks on an approx. exponential background in mass!

In-medium modifications of e+e- and  +  - spectra W. Cassing, Nucl.Phys.A674: ,2000.

Chiral Magnetic Effect (CMF)

Chiral Magnetic Effect Non-central heavy-ion collisions Large orbital angular momentum (L) 90 o to RP Strong localized B-field (due to net charge of system) If system is deconfined, can have strong P-violating domains & different no. of left-& right-hand quarks Preferential emission of like-sign charged particles along

Chiral Magnetic Effect - Strong Parity Violation?

Observables: Penetrating probes: , , , → e+e- (μ+μ-) Strangeness: K, , , , , global features: collective flow, fluctuations,..., exotica The NICA experimental program Systematic investigations: A+A collisions from 8 to 45 (35) AGeV, Z/A=0.5 (0.4) p+A collisions from 8 to 90 GeV p+p collisions from 8 to 90 GeV Large integrated luminosity: High beam intensity and duty cycle, Available for several month per year Detector requirements Large geometrical acceptance (azimuthal symmetry !) good hadron and electron identification excellent vertex resolution high rate capability of detectors, FEE and DAQ

MPD general view Central Detector - CD & two Forward Spectrometers (optional) – FS-A & FS-B

CD dimension

TPC ECal ZDC TOF RPC EC Tracker MPD scheme 3 stages of putting into operation 2-nd stage IT,EC-subdetectors 3-d stage F-spectrometers (optional ?) 1-st stage barrel part (TPC, Ecal, TOF) + ZDC, BBC, S-SC, …

MPD conceptual design Inner Tracker (IT) - silicon strip detector / micromegas for tracking close to the interaction region. Barrel Tracker (BT) - TPC + Straw (for tagging) for tracking & precise momentum measurement in the region -1 <  < 1 End Cap Tracker (ECT) - Straw (radial) for tracking & p-measurement at |  | > 1 Time of Flight (TOF) - RPC (+ start/stop sys.) to measure Time of Flight for charged particle identification. Electromagnetic Calorimeter (EMC) for  0 reconstruction & electron/positron identification. Beam-Beam Counters (BBC) to define centrality (& interaction point). Zero Degree Calorimeter (ZDC) for centrality definition. MPD basic geometry Acceptance

 MPD main features (advantages)  The CDR development is continued  R&D activity is in progress  The MPD Collaboration is growing MPD Summary  capability to work at high luminosity  high rate of event recording  hermeticity - towards 4  geometry  smooth scan in - relevant energy region - A-number - b-parameter

Booster-sinhrotron appliction to nanostructures creations: Applied research at NICA Booster Electron cooling system Design and parameters of booster, including wide accessible energy range, possibility of the electron cooling, allow to form dense and sharp ion beams. System of slow extraction provides slow, prolongated in time ion extraction to the target with space scanning of ions on the target surface and guaranty high controllability of experimental conditions. Ion tracks in a polymer matrix (GSI, Darmstadt) Ion-track technologies: Topography and current of a diamond-like carbon (DLC) film.The 50 nm thick DLC film was irradiated with 1 GeV Uranium ions. Production of nanowires, filters, nanotransistors,...

The planned steps: More close collaboration with Russian institutes and JINR Member StatesMore close collaboration with Russian institutes and JINR Member States Strengthening the relations with FAIR, RHIC and CERN where similar works are carried out (MoU)Strengthening the relations with FAIR, RHIC and CERN where similar works are carried out (MoU) Profiling students of the Dubna University with orientation towards NICA/MPD problemsProfiling students of the Dubna University with orientation towards NICA/MPD problems Organization of student Schools and Meetings for young scientists on problems of NICA/MPDOrganization of student Schools and Meetings for young scientists on problems of NICA/MPD

Thanks for your attention! Welcome to the NICA collaboration!

Welcome to Dubna!