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Physics at NICA

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.

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Physics at NICA

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  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 Richard Lednický GDRE Nantes ‘2010

  2. Evidence for deconfinement at SPS • - 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/y suppression in central A+A QGP HG Mixed phase Quarkonium suppression by color screening

  3. Evidence for deconfinement at RHIC • Large elliptic flow: v2/ close to ideal liquid value at top RHIC energies • CQNS of v2 • Jet quenching 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

  4. Lessons from the 1st generation HI experiments • 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..)

  5. Motivation for the next generation of HI experiments 3nd generation experiment with dedicated detectors are required for more sensitive and detailed study

  6. 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+, too few energies. 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, max. energies in 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+ at 9 GeV.

  7. 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).

  8. FREEZE-OUT AND PHASE DIAGRAMS Critical end-point 1st order PT Ivanov, Russkikh,Toneev ’06 : At lower energies the system spents an essential time in the mixed phase Randrup, Cleymans ‘06 : NICA&FAIR sNN = 9 AGeV The freeze-out baryon density is maximal at sNN= (4+4) GeV covered by NICA and FAIR 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

  9. 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

  10. Thermal Model

  11. if added heavy resonances (motivated by e+e-) + 

  12. !

  13. Lattice says: crossover at µ = 0 but CP location is not clear CP: T ~ 170 MeV, μB > 200 MeV

  14. QCD phase diagram • The most intriguing and little studied • region 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 Deconfined matter (high e,T,nB): e >1 GeV/fm3, T>150 MeV, nB>(3-5)n0 Challenge: comprehensive experimental program requires scan over the QCD phase diagram by varying collision parameters : system size, beam energy and collision centrality

  15. CP:  ______ _________ ___ 

  16. CP signals in multiplicity and pt fluctuations for ξ =3 and 6 fm assuming CP at T=162 MeV µB=360 MeV & Gaussian fluctuation shape with the width of 10 MeV in T 30 MeV in µB ω= D(N)/‹N› pt = (D(∑pti)/‹N›)1/2-(D(pt))1/2 pt  40 (10) MeV/c for ξ =6 (3) fm  10 (2.5) for NA49 acc.= 0.24 M. 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

  17. Cassing – Bratkovskaya: Parton-Hadron-String-Dynamics Perspectives at FAIR/NICA energies

  18. 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 v2 for midrapidity 25% most central collisions v2/ε vs particle density in the transverse plane AGS RHIC IDEAL SPS

  19. Rischke & Gyulassy, NPA 608, 479 (1996) With 1st order Phase transition Femtoscopic signature of QGP 3D 1-fluid Hydrodynamics 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 0is reached •  decreases with decreasing Latent heat & increasing tr. Flow • (high 0 or initial tr. Flow)

  20. Femto-puzzle I Small space-time scales at RHIC energies – basically solved due to the initial 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

  21. Radii vs fraction 1 of the large scale: very weak sensitivity r  solving Femtoscopy Puzzle II r1 Input: 1, 2=1-1, r1=15, r2=5 fm 1-G Fit: r ,  2-G Fit: 1, 2, r1,r2 r2  2 1 1 1 Typical stat. errors in 1-G (3d) fit  (r1)/0.06 fm 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  (1)/0.01 1

  22. Imaging

  23. 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 emision time (femtoscopy) • Strangeness and resonace production • Exotic strange multibaryon states with L,p,p,K0

  24. 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? ½ = ½ + G + Lq + Lg Recent data (CERN, DESY, JLAB, SLAC):   0.3 quark contribution gluon contribution |G| < 0.3 Lq, Lg – angular orbital momentum contributions (unknown) DG is less then speculated  missing spin contribution (“spin crisis” continues) New (precise) measurements of many (new) PDFs (Parton Distribution Functions) required

  25. Spin physics @ NICA (2) • NICA advantages: • Beams – p,d(h), L ~ 1032 cm-2s-1 • Polarization – transversal and longitudinal ( > 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

  26. Spin physics @ NICA (3)

  27. Spin physics @ NICA: polarized MMT-DY The SSA for 100kDY events: 3 years of running sin(+S): access to transversity& Boer-MuldersPDFs Sissakian, Shevchenko, Nagaytsev, PRD 72 (2005), EPJ C46 (2006) sin(-S): access to SiversPDFs Efremov,… PLB 612(2005), PRD 73(2006)

  28. Experiments on MMT-DY measurements

  29. Conclusions I • FO points calculated within Thermal Model seem to be close to QGPphase 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 NICA

  30. Conclusions II • 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

  31. 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

  32. Welcome to the collaboration! Thank you for attention! R. Lednicky April 2, 2008 A.N.Sissakian, A.S.Sorin 35

  33. Spare Slides

  34. Cassing – Bratkovskaya:

  35. BW: Retiere@LBL’05 pion 0.73c 0.91c , , Flow & Radii x-out, y-side, z-long ← Emission points at a given tr. velocity px = 0.15 GeV/c 0.3 GeV/c Rz2 2 (T/mt) Ry2 = y’2 Kaon Rx2= x’2-2vxx’t’+vx2t’2 t’2  (-)2  ()2 px = 0.53 GeV/c 1.07 GeV/c For a Gaussian density profile with a radius RG and linear flow velocity profile F(r) = 0r/ RG: Proton Ry2 = RG2 / [1+ 02 mt /T] px = 1.01 GeV/c 2.02 GeV/c Rz  = evolution time Rx  = emission duration Rx , Ry0 = tr. flow velocity pt–spectra  T = temperature

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