Exochim & Farcos collaboration: L. Acosta, F. Amorini, A. Anzalone, L. Auditore, G. Cardella, A. Chbihi, E. De Filippo, L. Francalanza, E. Geraci, C. Guazzoni, E. La Guidara, G. Lanzalone, I. Lombardo, S. Lo Nigro, D. Loria, I. Martel, T. Minniti, E.V. Pagano, A. Pagano, M. Papa, S. Pirrone, G. Politi, F. Porto, F. Rizzo, P. Russotto, S. Santoro, A. Trifirò, M. Trimachi, G. Verde, M. Venhart, M. Veselsky, M. Vigilante NSCL-Michigan State University Z. Chajecki, P. Danielewicz and B. Barker Acknowledgements

Dynamics and correlation INFN-Catania Catania LNS Tandem (15 MV)EA ≤ 10 MeV Superconducting Cyclotron K800 G. Verde & Exochim coll., INFN-CT, INFN-LNS, Univ. of Catania, LNS

Chimera… our “Alice” for intermediate energies… 1m 1° 30° TARGET 176° Beam 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)

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

Farcos project: femtoscopy capabilities Stay tuned! Talk by T. Minniti, INFN-CT and University of Messina

What do you mean by “low energies”? Dynamics/Thermodynamics EoS, Asy-EoS Space-time probes required (Two-particle correlations, Femtoscopy, emission chronology, time-scales, etc.) Intermediate energies: E/A= MeV Medium (GSI) energies: E/A= MeV

High energy Vs.“low” energies Different interpretations, different models, different physics goals (not always, i.e. elliptic flow etc.), … Similar space- and time-scales involved: – R ~ 2-10 fm – τ ~ fm/c Share analysis techniques, ideas, detection technologies…

The EoS of asymmetric nuclear matter Infinite nuclear matter: how does E depend on density? ??? B.A. Li et al., Phys. Rep. 464, 113 (2008) Many approaches… large uncertainties…. Microscopic many-body, phenomenological, variational, …

Asy-Stiff Asy-Soft Producing density gradients in HIC SMF - Baran, Colonna, Di Toro, Greco Intermediate energies: E/A= MeV Ganil, Eurisol, Frib, Lns, Nscl, Spiral2, Tamu, … High energies: E/A>200 MeV CSR, GSI/Fair, NSCL/FRIB, Riken, … Neutron Stars Radii Frequencies of crustal vibrations Composition, thickness of inner crust URCA processes Phases within the star Densities ~ 0.01ρ 0 - 6ρ 0 – Large Gradients!!!

Probes of the symmetry energy Probes at Intermediate energies: sub-saturation density Asy-EoS (ρ<ρ 0 ) – Isospin diffusion and drift – Neutron-proton pre-equilibrium emission – nn, np, pp correlation functions Probes at GSI energies: supra-saturation density Asy-EoS (ρ>ρ 0 ) – π + /π- and K + /K 0 emission ratios – n/p elliptic flow – n/p pre-equilibrium emission ρ 0 ~ 0.17 fm -3

Effects of the E sym at high density N/Z of high density regions sensitive to E sym (ρ) High ρ  ρ 0 : asy-stiff more repulsive on neutrons - opposite of sub-saturation trend stiffness B.A. Li et al., PRC71 (2005) ≈(ρ/ρ 0 ) γ

Elliptic flow: competition between in plane (V 2 >0) and out-of-plane ejection (V 2 <0) z x V2V2 y Y = rapidity p t = transverse momentum High densities: flows UrQMD vs. FOPI data: 400 A MeV 5.5<b<7.5 fm Qingfeng Li, J. Phys. G (2005) P.Russotto et al., Phys. Lett. B 697 (2011)

ASY-EOS experiment (May 2011) “possible“ 1 st phase toward FAIR ??? (e.g. 132 Sn, 106 Sn beams) 400 AMeV 96 Zr AMeV 96 Ru AMeV ~ 5x10 7 Events for each system ASY-EOS S394 GSI Darmstadt (Germany) Beam Line Shadow Bar TofWall Land (not splitted) target Chimera Krakow array MicroBall P. Russotto, INFN-CT

Chimera for event shape: reaction plane, impact parameter LAND: neutrons and protons  elliptic flow P. Russotto, INFN-CT

g32new Kinematics Centrality dependence sorted using transverse energy of LCP (Z≤2) 400 AMeV proj mid P. Russotto, INFN-CT

Pion ratios: controversial results…. Zhigang Xiao et al. PRL 102 (2009) IBUU04: Supersoft IBUU04 ImQMD: superstiff Zhao-Qing Feng, Gen-Ming Jin, Phys.Lett.B683, 2010 ??? ?

Pion and Kaon freeze-out in HIC Warning with pions: Strongly interacting in medium Freeze-out at late times (low   ) Difficult to isolate π+ and π- produced in the high density stage Low  0 High  0 Kaons: more sensitive probes? Higher thresholds Weakly interacting in medium Freeze-out already at 20 fm/c: real high density region probes K +,K 0 π +, π - RBUU, Ferini et al., PRL97,

HIC at Fermi energies: E sym (ρ) at ρ<ρ 0 b=peripheral PLF TLF Isospin diffusion & drift Pre-equilibrium emission Expansion Multifragmentation b=central b=mid-peripheral Neck fragments PLF TLF Neck, low ρ  isospin drift

Isospin diffusion TLFPLFNeck      n/p diffusion Isospin drift & diffusion ρ  ~1/8ρ 0 ρ~ρ 0 ρ  ~ρ 0 n drift Isospin drift TLFPLFNeck ρ/ρ   E sym vs ρ Asy-Stiff Asy-Soft Low ρ  ρ 0 Isospin equilibration Long τ int Isospin translucency Short τ int Proj Targ TLF PLF TLF PLF Colonna et al.; Danielewicz et al.

Event characterization TLFPLFIMFTLFPLFIMF TLF~ PLF~ IMF~ IMF Characterize IMF emission IMF times 3  M c  6 *b red >0.6 7  M c  <*b red <0.6 M c >12 *b red < Sn MeV/u

TLF seq. emission Time-scales from three-fragment correlations PLF seq. emission V rel (IMF-PLF) / V Viola V rel (IMF-TLF) / V Viola PLF TLF IMF intermediate TLF PLF IMF Prompt emission from neck 1

Emission time-scales and chronology fm/c 1 40 fm/c fm/c Light fragments are produced earlier than heavier ones ~40 fm/c vs ~120 fm/c Simultaneous Sequential E. De Filippo, P. Russotto, A. Pagano Phys. Rev. C (2012)

Isospin chronology LiBe B C 124 Sn + 64 Ni 35 A.MeV Prompt emissions more neutron rich neutron-enrichment in neck emissions E. De Filippo, P. Russotto PRC (2012)

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

Femtoscopy in HIC p-p NSCL n-n LNS γ-γ GANIL LCP-IMF GANIL IMF-IMF LNS d-α NSCL 1+R(q) q (MeV/c) GSI p-α p-p GSI

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

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

Lednicky recipe: p-n correlations 1+R + (q) 1+R − (q) Ratio +/- Ratio R+/R- tells us which is emitted first R. Lednicky et al., Phys. Lett. B373, 30 (1996) Nuclear FSI q (MeV/c) n first +100 fm/cn first +50 fm/cp first -100 fm/c p-n

Isospin effects on p-p R 48Ca+ 48Ca > R 40Ca+ 40Ca 48 Ca+ 48 Ca vs 40 Ca+ 40 Ca E/A=80 MeV - Central CorrelationsEmitting sources Larger size for more n-rich system:  N/Z effect? Size effect? Asy-EoS? σ NN Z. Chajecki, et al. Phys. Rev. C (2012)

Multi-Particle Correlation Spectroscopy (MPCS) – “non-femtoscopic” stuff… HIC and correlations as a spectroscopic tool Cluster states in stable and exotic nuclei BEC, Hoyle Expansion Not only EoS… Several unbound species in just one single experiment! 10 C*

8 B unbound state: spin determination States of 8 B  p+ 7 Be p+ 7 Be (?) B8B p- 7 Be correlations W.P. Tan et al. Phys. Rev. C69, (2004) 7 Be 8B8B p Xe+AuE/A50 MeV Central collisions

Sequential decay modes: multi-particle correlation functions Peripheral projectile fragmentation 12 C+ 24 MgE/A=53, 95 MeV Decay of 12 C and 10 C quasi projectiles (QP*) 12 C*  α + α + α 10 C*  α + α + p + p α + 8 Be α + α 2p+ 8 Be α+α p+ 9 B α+ α+p α+ 6 Be α+2p 2α+2p direct α + α + α direct Hoyle states? Boson condensate?

2α-2p correlations : states in 10 C* E k (MeV) 10 C  6 Be+α  (2p+α)  α 10 C  8 Be+p+p  (α+α)+  p 10 C  9 B+p  (  +α  α)  p F. Grenier et al., Nucl. Phys. A811 (2008) 233

Search for Hoyle states in Nα nuclei Three-alpha correlations 12 C*  α + α + α Gated 8 Be*  α + α No direct three-body decay of Hoyle state in 12 C J. Manfredi, R.C. Charity et al., PRC 2012 A. Raduta et al., Phys. Lett. B705, 65, Ca+ 12 C, E/A=25 Chimera 12 C  3 alpha Γ~ 7.5% direct three-body decay (BC?)

Conclusions Probes of symmetry energy at high density: – GSI energies: n/p flow – π + /π- and K + /K 0 emission ratios – Understand where and when π’s and K’s are produced… correlation techniques (?) Probes of symmetry energy at low density: – Intermediate energies: Isospin diffusion and drift;  moderately soft symmetry energy (γ~ ) – Still missing probes from femtoscopy  future projects “non-femtoscopic” correlations to learn about new phenomena and exotic nuclear systems