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Z oran Basrak

Studies of symmetry energy a t supra-saturation densities at FAIR. Z oran Basrak. Laboratory for nuclear physics Division of Experimental Physics R uđer Bošković Institute, Zagreb, Croatia. R 3 B collaboration meeting April 15, 2010, Darmstadt, Germany. 1950 – 2010. Outline.

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Z oran Basrak

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  1. Studies of symmetry energy at supra-saturation densities at FAIR Zoran Basrak Laboratory for nuclear physics Division of Experimental Physics RuđerBošković Institute, Zagreb, Croatia R3B collaboration meeting April 15, 2010, Darmstadt, Germany 1950 – 2010

  2. Outline • Introduction • Symmetry energy • Low densities • High density • Ongoing projrcts • Summary and outlook

  3. E (,T ) =E (r,T=0) + E’(r,T ) Eliptic flow v2 Side flow v1 Data from KAOS P. Danielewicz et al., Science 298 (2002) 1592 C. Fuchs et al., PRL 86 (2001) 1974 Nuclear EOS N = Z From the nuclear monopole resonance* K∞ of symmetric nuclear matter K∞ = 231 ± 5 MeV *D.H. Youngblood et al., PRL 82 (1999) 691

  4. L.W. Chen et al., PR C80 (2009) 014322 BHF RMF Skyrme Nuclear EOS – Asymmetric term Bethe – Weizsäcker mass formula B (N,Z) =aVA- aSA2/3 – aCZ (Z - 1)/A1/3-asym (N – Z )2 / A+ Δ(A) asym = 23.7 MeV E(,) = E(,0) + 2Esym()+ O(4)  = (n- p) /  = (N-Z)/A Esym() ≈E()neutr. matter - E()sym. nucl. matter Various notations: Esym() = S(),  = x = I many more in:B.A. Li et al., PhRep. 464 (2008) 113

  5. C. Fuchs and H.H. Wolter, EuPhJ A30 (2006) 5 Symmetry energy • The density dependence of symmetry energy is largely unconstrained. • What is “stiff” or “soft” (curvature) is density dependent Z. Xiao et al., PRL102 (2009) 062502 The asymmetry term contributes a greater uncertainty than does the symmetric matter EOS. (Bao-An Li)

  6. GDR & PYGNY RESONANCE p / n≤ 0.1 – 0.2 c≤ (2-15)0 Supernova collapse Where Esym shows up Nuclear structure Nuclear reactions

  7. Neutron star Esymdependent • Stability against gravitational collapse • Radial density profile • Internal structure, composition and evolutio • Cooling mechanism J.M. Lattimer and M. Prakash, Science 304 (2004) 536 Observables • Cooling rates of proto-neutron star • Cooling ratesfor X-ray bursters • NS masses, radii and moments of inertia

  8. p, n P N after before By HIC in the Fermi energy regime Constraining Esym Nuclear structure data Intermediate & relativistic energy HIC Isospin sensitive observables - n/p differential flow - meson production, π+/π-,K0 /K+ - etc. Lack of data, but … - ASY-EOS experiment @ GSI - SAMURAI @ RIKEN Intermediate & relativistic energy HIC Isospin sensitive observables - n/p differential flow - meson production, π+/π-,K0 /K+ - etc. Finite symmetry energy at zero energy due to clustering effects

  9. Esym as f(ρ) from MSU data BUU transport model calculation without momentum dependence Esym/A = 12.5(r/r0), = 2 M.B. Tsang et al., PRL 92 (2004) 062701 Isospin- and momentum-dependent IBUU04 model calculation with the Gogny effective interaction Esym/A = 31.6(r/r0), = 1.05 L.W. Chen et al., PRL 94 (2005) 032701 Added in-medium modifications of NN cross sections Esym/A = 31.6(r/r0), = 0.69 B.A. Li & L.W. Chen, PRC 72 (2005) 064611

  10. (Courtesy of W.G. Lynch) Sub-saturation densities Two parameterizations HIC fited by transport codes IBUU04, ImQMD P. Danielewicz and Lee, NPA 818 (2009) • Esym()= 12.5·u2/3 + C·uγ u = ρ/ρ0 Isobaric analog states & Pygny dipole resonance M.B. Tsang et al.,PRL 102 (2009) 122701 A. Klimkiewicz et al., PRC 76 (2007) 051603 Expansion around ρ0 Esym(ρ)= S0 + L·ξ/3 + Ksym·ξ2/18 + …,ξ = (ρ - ρ0)/ρ0 Symmetry slope L & curvature Ksym L = 3·[∂Esym/∂ρ]ρ=ρ0/ρ0 = 3·Psym /ρ0

  11. Z.Q. Feng, G.M. Jin, PL B683 (2010) 140 (Courtesy of M.B. Tsang) Supra-saturation densities The only available data (FOPI and FOPI–LAND) result in a contradictory predictions for Esym: • n-p squeeze-out data from Au+Au collisions at E = 400A MeV [Y. Leifels et al., PRL 71 (1993) 963] →the UrQMD code predicts a steady rise of Esym → γ=0.60.3[W. Trautmann et al., ProgPartNuPh (2009)]. • n-p squeeze-out data from Au+Au collisions at E = 400A MeV [Y. Leifels et al., PRL 71 (1993) 963] →the UrQMD code predicts a steady rise of Esym → γ=0.60.3[W. Trautmann et al., ProgPartNuPh (2009)]. • π+-/π+ yield ratio data for Au+Au collisions in a broad energy range [Reisdorf et al., NP A781 (2007) 459] →the IBUU04 code predicts a vanishing Esym → γ=0.960.21, super soft asyEOS[Z. Xiao et al., PRL 102 (2009) 062502].

  12. Constraining Esym (>0) Two experimental proposals: - GSI: n-p differential flow - Nishina / RIKEN: pion production

  13. SIS18 ASY-EOS experiment S394 Spoakpersons of ASY-EOS experimentR. Lemmon and P. Russotto (approved by GSI-PAC) Zagreb, Croatia Caen, Orsay, France Darmstadt, Frankfurt, Germany Ioannina, Greece Catania, Milano, Napoli, Italy Katowice, Krakow, Warsaw, Poland Bucharest, Romania Santiago de Compostela, Spain Lund, Malmo, Sweden Daresbury, Liverpool, United Kingdom Kolkata, India NSCL-MSU, Rochester, USA

  14. Au+Au @ 400A MeV (increased statistics) 96Zr+96Zr @ 400A MeV 96Ru+96Ru@ 400A MeV Lund-SdC Califa } (increased isospin sensitivity) MSU miniball .5 m IPJ phoswich GSI LAND LNS Chimera SIS18 ASY-EOS experiment S394 Main observable: n/p differential flow Detect: n, p, t, 3He, N/Z of light IMFs Determine: reaction plane, reaction centrality Improve: statistics and neutron background determination + code clusterization algorithm

  15. Towards FAIR 132Sn, 106Sn beams

  16. SAMURAI A/Z = 3Ekin = 250A MeVBρ = 7.3 Tm B.A. Li, PRC 67 (2003) 017601 AT-TPC RIKEN experiment Main partners: MSU & RIKEN Main requirements: - pion detector with large solid angle - centrality filter Solution: - SAMURAI superconducting dipole - TPC detector – should be operational in 2014 - and many more (neutron wall, light charged particles, IMFs, …)

  17. Murakami @ TPC workshop, MSU

  18. Murakami @ TPC workshop, MSU

  19. NSF-PIRE project NSCL-MSU (M.Y.B. Tsang) abd collaborators have started a Partnerships for International Research & Education (PIRE) project: collaborative research between US, Japan and Europe[MSU, RIKEN, GSI (FAIR)] • differences in available - beams, - energies, and - intensities • different observables chosen • complementary parts in a global effort to constrain symmetry energy

  20. European Science Foundation Research Networking Programmes Constraining the Symmetry Energy CoSymE Z. Basrak, M. Colonna and W. Trautmann

  21. What for ? • Creation of discussion fora • Exchange of students & experts • Facilitate a global dimension (complementarities to NSF-PIRE) • Timely initiative • Prepare future - new intensive RIB facilities - train up a new generation of scientists to take over leadership • Open character

  22. Who ? European Science Foundation 30 member states

  23. Who ? European Science Foundation 30 member states

  24. Road map ? • Selection outcome – June 2010 • Re-submission of full list of the collaborating institutions and supporting agencies – mid October 2010 • Launching CoSymE – January 2011 More info: -https://www.irb.hr/users/mkis/pdf/Cosyme.pdf - basrak@irb.hr

  25. Esym related activities • FOPI days in Split, May 2005 • LAND Collaboration Meeting, 2006 • Chimera-GSI Workshop, Dec. 2006 • FOPI Collaboration Meeting, Apr. 2007 • Asy-EOS Workshop, Catania, June 2008 • R3B Collaboration Meeting, GSI, Apr. 2009 • ESF Exploratory Workshop, Zagreb, Oct. 2009 • Letter of Intent, spring 2008 • Proposal for GSI PAC, spring, 2009 • Submitted ESF RNP CoSymE, Oct. 2009 • Asy-EOS 2 Workshop, Noto/Sicily, May 2010

  26. Open Q’s & problems • What is an adequate parameterization ofEsym = f(r/r0) ? • What is an adequate parameterization ofEsym = f(N-Z) ? • Although of fundamental importance,isovector effects on EOS areweaker thanthose of symmetric matter • Strong in-medium effects • Subtle choice of multiple& cross-checkobservables + subtle phase-space cuts

  27. Solutions • To cancel or at least minimize “symmetric” .background take isobaric ratios • To maximize isovector effects study pairs.of systems whit largest neutron excess • Measure excitation functions to enhance . sensitivity • Make multiple cuts: y, pt, F, … • High statistics of data taking • Beamof highintensity

  28. Supra-saturation densities • p- / p+ ratio • K- / K+, K+ / K0 • neutron-proton differential transverse flow • n / p ratio (@ mid-rapidity) • t / 3He ratio • nucleon elliptical flow at high transverse . momenta • isospin transparency • deconfinement precursors (?) • …

  29. Summary and outlook • Theory highly ambiguous: seeks inputs from experiment in the range 1<r/r0<5. • Astrophysics (supernova dynamics and compact stars): any input is welcome. • Present simulations are non-conclusive.Only measurement could cut on the symmetry energy term of nuclear EOS. • Theory highly ambiguous: seeks inputs from experiment in the range 1<r/r0<5. • Astrophysics (supernova dynamics and compact stars): any input is welcome. • Present simulations are non-conclusive.Only measurement could cut on the symmetry energy term of nuclear EOS. • FAIR and super-FRS offer high intensity relativistic radioactive beams while R3B offers an adequate detection instrumentbest suited to constrain the symmetry E.

  30. Studies of symmetry energy at supra-saturation densities at FAIR Thank you for your attention Zoran Basrak Laboratory for nuclear physics Division of Experimental Physics RuđerBošković Institute, Zagreb, Croatia R3B collaboration meeting April 15, 2010, Darmstadt, Germany 1950 – 2010

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