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Correlations and space-time probes in Heavy-Ion collisions

Correlations and space-time probes in Heavy-Ion collisions. OUTLINE: The Asy-EoS and the role of space-time probes Experimental probes with Chimera and Correlation measurements Conclusions and perspectives. G. Verde, INFN-CT Chimera & Farcos groups, INFN-CT, INFN-LNS, Un. Of Catania.

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Correlations and space-time probes in Heavy-Ion collisions

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  1. Correlations and space-time probes in Heavy-Ion collisions • OUTLINE: • The Asy-EoS and the role of space-time probes • Experimental probes with Chimera and Correlation measurements • Conclusions and perspectives G. Verde, INFN-CT Chimera & Farcos groups, INFN-CT, INFN-LNS, Un. Of Catania Zimanyi School 2012 Budapest 3-7 Dec, 2012

  2. IstitutoNazionale di FisicaNucleare, Catania and LNS LNS Catania K800 Tandem (15 MV) EA ≤ 10 MeV Superconducting Cyclotron

  3. Intermediate energies: E/A=20-100 MeVMedium Energies: E/A=100-1500 MeV Dynamics/Thermodynamics EoS, Asy-EoS Space-time probes required (Two-particle correlations, Femtoscopy, emission chronology, time-scales, etc.)

  4. Symmetry energy in finite nuclei Bethe-Weiszacker 16O

  5. B.A. Li et al., Phys. Rep. 464, 113 (2008) ??? Many approaches… large uncertainties…. Microscopic many-body, phenomenological, variational, … The EoS of asymmetric nuclear matter Infinite nuclear matter: how does E depend on density? Typical parameterizations γ ~ 2 ~ Asy-Stiff γ< 0.5~ Asy-Soft

  6. Intermediate energies: E/A=20-100 MeV High energies: E/A>200 MeV CSR, GSI/Fair, NSCL/FRIB, Riken, … Ganil, Eurisol, Frib, Lns, Nscl, Spiral2, Tamu, … SMF - Baran, Colonna, Di Toro, Greco Asy-Stiff Asy-Soft Producing density gradients in the lab Neutron Stars • Radii • Frequencies of crustal vibrations • Composition, thickness of inner crust • URCA processes • Phases within the star Densities ~ 0.01ρ0 - 6ρ0 – Large Gradients!!!

  7. Isolating symmetry energy effects • Symmetry energy effects are small! • Reactions with same Ebeam and different N/Z Enhance effects by increasing δ2 factor ~ (N-Z)2/A2 112Sn + 112Sn 112Sn + 124Sn

  8. Beam TARGET 30° 176° 1° 1m Chimera @ INFN-LNS 1192 Si-CsI(Tl) Telescopes 18 rings in the range 1° ≤ θ ≤ 30° 17 rings in the range 30° ≤ θ ≤ 176° (sphere) High granularity and efficiency up to 94% 4π • Z identification up to beam charge (ΔE-E) • Z and A identification by ΔE-E up to Z≤ 9 • Z and A identification in CsI up to Z ≤ 4 • Mass identification with low energy threshold (< 0.3 MeV/u) by ToF • Z identification for particles stopping in Si (pulse shape)

  9. Be Li HI a 3He t d p CsI (Tl) Si Particle identification in Chimera PSD in CsI(Tl) Z and A for light charged particles ΔE(Si)-E(CsI) Charge Z for particles punching throught the Si detector t V(t) slow fast ΔE(Si)-ToF Mass for particles stopping in the Si detector gate 3-12 cm ~300 μm E(Si)-Rise time Charge Z for particle stopping in Si detectors (NEW) ΔE(Si)-E(CsI) Charge Z and A for light ions (Z<9) punching throught the Si detector

  10. FARCOS add-in: Femtoscopy 4 CsI(Tl) crystals (3rd stage) DSSSD 1500 μm (2nd stage) Assembly cluster DSSSD 300 μm (1st stage) 132 channels by each cluster Based on (62x64x64 mm3) clusters 1square(0.3x62x62mm3)DSSSD 32+32 strips 1square (1.5x62x62mm3)DSSSD 32+32 strips 460x32x32 mm3CsI(Tl) crystals Talk by Emanuele Pagano

  11. Probes of the symmetry energy • Probes at Intermediate energies: sub-saturation density (ρ<ρ0) • Isospin diffusion and drift • Neutron-proton pre-equilibrium emission spectra • nn, np, pp correlation functions • Probes at GSI energies: supra-saturation density (ρ>ρ0) • π+/π- and K+/K0 emission ratios • n/p elliptic flow • n/p pre-equilibrium emission and correlation functions

  12. Effects of the Esym at high density B.A. Li et al., PRC71 (2005) E/A = 400 MeV • N/Z of high density regions sensitive to Esym(ρ) • High ρ>ρ0: asy-stiff more repulsive on neutrons ≈(ρ/ρ0)γ stiffness stiffness

  13. z x V2 y Elliptic flow in HIC at medium energies UrQMD vs. FOPI data: Au+Au @ 400 A MeV Y=rapidity, pt=transversemomentum 5.5<b<7.5 fm Elliptic flow: competitionbetween in plane (V2>0) and out-of-planeejection (V2<0) Qingfeng Li, J. Phys. G31 1359-1374 (2005) P.Russotto et al., Phys. Lett. B 697 (2011)

  14. ASY-EOS S394 experiment @ GSI Darmstadt (Germany) Au+Au @ 400 AMeV 96Zr+96Zr @ 400 AMeV 96Ru+96Ru@ 400 AMeV ~ 5x107 Events for each system TofWall Beam Line ASY-EOS experiment (May 2011) Krakow array Chimera target Shadow Bar MicroBall Land (notsplitted) P. Russotto, INFN-CT

  15. Preliminary results on neutron flow Centrality (Etrans) Au+Au @ 400 AMeV v1 Data Model v2 ylab preliminary P. Russotto, INFN-CT g32new

  16. High ρ/ρ0 Pion and Kaon freeze-out in HIC Low ρ/ρ0 π+, π- K+,K0 RBUU, Ferini et al., PRL97, 202301 • Warning with pions: • Strongly interacting in medium • Freeze-out at late times (low ρ/ρ0) • Difficult to isolate π+ and π- produced in the high density stage • Kaons: more sensitive probes? • Higher thresholds • Weakly interacting in medium • Freeze-out already at 20 fm/c: more reliable as high ρ probes

  17. Multifragmentation Expansion Pre-equilibrium emission b=central 1 2 b=mid-peripheral Neck, low ρ, isospin drift Neck fragments PLF 3 TLF b=peripheral Isospin diffusion & drift PLF 4 TLF HIC at Fermi energies: Esym(ρ) at ρ<ρ0

  18. Isospin equilibration Long τint Esymvsρ Asy-Stiff Short τint Asy-Soft Isospin translucency Isospin drift Isospin diffusion ρ/ρ0 1 n drift N/Z Proj Targ TLF Neck PLF n/p diffusion TLF Neck PLF Isospin drift & diffusion ρ~ρ0 PLF PLF PLF Targ Proj ρ~1/8ρ0 ρ~ρ0 TLF TLF TLF Low ρ<ρ0 Colonna et al.; Danielewicz et al.

  19. Event characterization with Chimera 124Sn+64Ni @ 35 MeV/u 7<Mc<12 0.2<*bred<0.6 Mc>12 *bred<0.2 3<Mc<6 *bred>0.6 TLF IMF PLF TLF IMF PLF TLF ~ IMF ~ PLF Characterize IMF emission IMF times

  20. Time-scales from three-fragment correlations seq. statistical emission from PLF TLF PLF IMF IMF intermediate TLF Vrel (IMF-TLF) / VViola Dynamical emission from neck PLF Vrel (IMF-PLF) / VViola seq. statistical emission from TLF

  21. 1 40 fm/c 2 80 fm/c 3 120 fm/c Emission time-scales and chronology E. De Filippo, P. Russotto, A. Pagano Phys. Rev. C (2012) Simultaneous 3 2 1 Light fragments: shorter time-scales compared to heavier ~40 fm/cvs~120 fm/c Sequential

  22. Li 124Sn + 64Ni 35 A.MeV Be <N/Z> C B Isospin chronology Dynamical emissions: more neutron rich neutron enrichment in neck emissions & sensistivity to Esym(ρ) E. De Filippo, A. Pagano, P. Russotto et al. PRC (2012)

  23. Sensitivity to symmetry energy P. Russotto, E. De Filippo, A. Pagano “Quasi”-Asy-Stiff (γ~0.8) more consistent with experimental results Dynamical Statistical E. De Filippo, A. Pagano, P. Russotto et al., Phys. Rev. C (2012)

  24. QP* QP* 124Sn QT* QT* QP* 112Sn QT* Isospindiffusion and imbalance ratios 112Sn+112Sn 112Sn+124Sn 124Sn+112Sn 124Sn+124Sn NN PP MIX MIX X=Y(7Li)/Y(7Be) Sensitive to N/Z of emitter Isospin transparency Ri(X) = 1 Isospin translucency 0 < Ri(X) < 1 Isospin equilibration Ri(X) = 0

  25. ImQMDγ=0.5 N/Ztranslucencypersists in centralcollision Isospin diffusion: Chimera-MSU coll. x = X7 = Y(7Li)/Y(7Be) Z.Y. Sun, M.B. Tsang, W.G. Lynch, G. Verde et al, PRC82 051603 (2010) 112,214Sn+112,124Sn E/A=35 MeV Ri ImQMD γ = 0.5 ImQMD γ = 2.0 Isospin diffusion excludes very stiff Esym(ρ)∝(ρ/ρ0)2.0

  26. Femtoscopy Imaging: Profile of emitting sources… space-time !images! Deuteron-Alpha correlations Final-state interactions + Coincidence pairs Y12 (q) + Uncorrelated pairs q (MeV/c) E.V. Pagano, G. Verde et al. Nuclear FSI: correlation at q=42 and 84 MeV/c Coulomb FSI: anti-correlation at small q values 1+R(q) 6Li High angular resolution required:  Low q and resonances deuteron-alpha q (MeV/c)

  27. neutron-neutron 7 5 3 1 1.5 1+R(q) 1.0 proton-proton 0.5 0.0 4 3 proton-neutron 2 1 q (MeV/c) NN correlations and symmetry energy Correlation functions IBUU simulations 52Ca+48Ca E/A=80 MeV Central collisions Asy-soft Asy-stiff Lie-Wen Chen et al., PRL (2003), PRC(2005) Proton/neutron emission times sensitive to density dependence of the symmetry energy

  28. Neutron-proton emission chronology Time delay between emissions Δt≠0 - Example: p emitted first Vp < Vn Vp > Vn p p p p n n Interaction attenuated Stronger interaction “particle catch-up”

  29. “Lednicky’s recipe”: p-n correlations p first -100 fm/c n first +100 fm/c 1+R+(q) R. Lednicky et al., Phys. Lett. B373, 30 (1996) Proton faster 1+R−(q) Neutron faster Ratio +/- p-n p-n q (MeV/c) q (MeV/c) R+/R- ratios tell who is emitted first Chronology Esym(ρ)

  30. Some preliminary N/Z effects on p-p 48Ca+48Ca vs40Ca+40Ca E/A=80 MeV - Central R 48Ca+ 48Ca > R 40Ca+ 40Ca Correlations Emitting sources Larger size for more n-rich system:  N/Z effect? Size effect? Asy-EoS? σNN Z. Chajecki, et al. Phys. Rev. C (2012)

  31. Conclusions • Probes of symmetry energy - high density: • GSI energies: n/p flow Chimera-LAND@GSI • π+/π- and K+/K0 emission ratios: future perspectives at RIKEN (SAMURAI/TPC,…) • Space-time probes of symmetry energy - low density: • Intermediate energies: Isospin diffusion and drift;  range of symmetry energies (γ~0.6-0.9)  still large error bars… • Femtoscopy and neutron observables  promising probes

  32. Acknowledgements All the Chimera, Farcos, Exochimgroups Special acknowledgements to students and postdocs

  33. WPCF IX – IX Workshop on Particle Correlations and Femtoscopy • Intensity interferometry, HBT in nuclear and particle physics, particle correlations in resonance decays • Synergy between High Energy and Intermediate Energy Heavy-ion collisions INFN-LNS Catania October 28-November 1, 2013 ANSiP-2013 – Advanced School and Workshop on Nuclear Physics Signal Processing • Signal processing in nuclear physics • Training in new analog and digital • Synergy with technologic research Acireale (CT) November 18-22 1, 2013

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