Isospin dependent EoS (Asy-EoS) with Heavy-ion collision probes

Transcription

1 Isospin dependent EoS (Asy-EoS) with Heavy-ion collision probes G. Verde INFN-CT for the Chimera & Farcos group OUTLINE: The Asy-EoS and the density dependence of the symmetry energy Experimental probes by the Chimera group (GSI and LNS experiments) Future perspectives for sub-saturation and suprasaturation density research Italy-Japan meeting Milano Nov, 2012

2 The EoS of asymmetric nuclear matter Infinite nuclear matter: how does E depend on density? E(r,d) = E r,d = 0 ( ) + E sym (r) d 2 + O d 4 ( ) d = r n - r p r n + r p B.A. Li et al., Phys. Rep. 464, 113 (2008)??? Many approaches large uncertainties. Microscopic many-body, phenomenological, variational, Typical parameterizations æ E sym (r) µ r ç è r 0 ö ø g γ ~ 2 γ < 0.5 ~ Asy-Stiff ~ Asy-Soft

3 Producing density gradients in the lab Intermediate energies: E/A= MeV High energies: E/A>200 MeV SMF - Baran, Colonna, Di Toro, Greco Ganil, Eurisol, Frib, Lns, Nscl, Spiral2, Tamu, Asy-Soft 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!!!

4 Constraints on E sym (ρ) Status of laboratory experiments Symmetry energy S. Gandolfi et al., Physical Review C85, (R) E sym (ρ) Neutron star Radii and Masses Still large error bars in laboratory measurements: Need to reduce uncertainties in HIC experiments

5 INFN-LNS 1192 Si-CsI(Tl) Telescopes 18 rings in the range 1 θ 30 Beam TARGET rings in the range 30 θ 176 (sphere) High granularity and efficiency up to 94% 4π 1 1m 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)

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

7 FARCOS add-in: Femtoscopy Based on (62x64x64 mm 3 ) clusters 1 square (0.3x62x62 mm 3 ) DSSSD strips 1 square (1.5x62x62 mm 3 ) DSSSD strips 4 60x32x32 mm 3 CsI(Tl) crystals 4 CsI(Tl) crystals (3rd stage) DSSSD 1500 μm (2nd stage) DSSSD 300 μm (1st stage) Assembly cluster 132 channels by each cluster Fully reconfigurable (more Si layers, neutron detection, )

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

9 Effects of the E sym at high density (ρ/ρ 0 ) γ B.A. Li et al., PRC71 (2005) E/A = 400 MeV stiffness stiffness N/Z of high density regions sensitive to E sym (ρ) High ρ>ρ 0 : asy-stiff more repulsive on neutrons

10 Elliptic flow in HIC at medium energies dn N0 ( y, pt ) 1 2 vn cos n( R ) d( ) 2 n 1 R Y=rapidity, p t =transverse momentum V 2 ( y, pt ) p 2 x p 2 t p 2 y UrQMD vs. FOPI data: 400 A MeV 5.5<b<7.5 fm Elliptic flow: competition between in plane (V 2 >0) and out-of-plane ejection (V 2 <0) y z x V 2 Qingfeng Li, J. Phys. G (2005) P.Russotto et al., Phys. Lett. B 697 (2011)

11 ASY-EOS S394 GSI Darmstadt (Germany) 400 AMeV ASY-EOS experiment (May 2011) 96 Zr AMeV 96 Ru AMeV ~ 5x10 7 Events for each system Beam Line Krakow array Chimera TofWall MicroBall target P. Russotto, INFN-CT Shadow Bar Land (not splitted)

12 Preliminary results on neutron flow Centrality (Etrans) 400 AMeV v 1 Data Model v 2 g32new preliminary y lab P. Russotto, INFN-CT

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

14 Isospin drift & diffusion ρ~ρ 0 Isospin equilibration PLF PLF PLF Targ Proj ρ ~1/8ρ 0 TLF TLF TLF ρ ~ρ 0 ρ/ρ 0 1 Isospin drift n drift TLF Neck PLF N/Z Pro j Tar g Isospin diffusion TLF Neck n/p diffusion PLF d = N - Z N + Z E sym vs ρ Isospin translucency j n - j p = ( D r r n - D p )Ñr - ( D d d n - D p )Ñd Low ρ<ρ 0 Asy-Soft Colonna et al.; Danielewicz et al.

15 Event characterization with Chimera 124 Sn MeV/u 3<M c <6 *b red >0.6 7<M c <12 0.2<*b red <0.6 M c >12 *b red <0.2 TLF IMF PLF TLF IMF PLF TLF ~ ~ PLF I Characterize IMF emission IMF times M

16 V rel (IMF-TLF) / V Viola Time-scales from three-fragment seq. statistical emission from PLF PLF IMF intermediate V rel (IMF-PLF) / V Viola correlations TLF V rel IMF ( IMF -TLF ) V rel ( IMF - PLF ) Dynamical TLF emission from neck V Viola = 2 * E C m Z Z2 E C =.755 1/3 A + A / PLF seq. statistical emission from TLF 7.3

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

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

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

20 Isospin diffusion and imbalance ratios 112 Sn+ 112 Sn 112 Sn+ 124 Sn 124 Sn+ 112 Sn 124 Sn+ 124 Sn PP MIX MIX NN X=Y( 7 Li)/Y( 7 Be) Sensitive to N/Z of emitter R i (X) = 2X - XNN - X PP X NN - X PP 124 Sn QT* QP* Isospin transparency R i (X) = 1 QT* QP* Isospin translucency 0 < R i (X) < Sn QT* QP* Isospin equilibration R i (X) = 0

21 Isospin diffusion: Chimera-MSU coll. x = X 7 = Y(7 Li)/Y(7 Be) R i (x) = 2x - x - x B+B A+A x B+B - x A+A 112,214 Sn+ 112,124 Sn E/A=35 MeV Z.Y. Sun, M.B. Tsang, W.G. Lynch, G. Verde et al, PRC (2010) ImQMD γ=0.5 R i ImQMD γ = 0.5 ImQMD γ = 2.0 N/Z translucency persists in central collision Isospin diffusion excludes very stiff E sym (ρ) (ρ/ρ 0 ) 2.0

22 N/Z effects at sub-fermi energies 40 Ca + 48 Ca, 40 Ca, 46 Ti E/A = 25 MeV model Incomplete fusion γ= Ca + 48 Ca 40 Ca + 40 Ca data HR M 1 γ=0.5 M 2 40 Ca + 40 Ca (N/Z=1) 40 Ca + 46 Ti (N/Z=1.05) 40 Ca + 48 Ca (N/Z=1.2) M 1 M 1 ~M CoMD-II HR 2 Binary reaction γ=1 M1 = Largest frament Mass I. Lombardo ΔM = (M 1 -M 2 )/M TOT Phys. Rev Lett (2009)

23 N/Z effects at low energies ISODEC: 78, 86 Kr + 40,48 Ca CN: 118, 134 Ba* (~ 250 MeV) S.Pirrone (INFN Catania), J.P.Wieleczko (GANIL- Caen), M.La Commara (Univ.& INFN Napoli), G.Politi (Univ. &INFN Catania) Topics to be addressed N/ Z effects on CN formation and decay: complex fragments production? Links to level density parameter (N/ Z-dependence), fission barriers, viscosity, spectroscopy interplay between nuclear structure and reaction mechanism Collaboration INFN-GANIL. LoI presented at Spes with radioactive beams (larger N/Z asymmetries)

24 IMF Isotopic Identification PSD in Silicon ΔE-E, Si-CsI(Tl) 10 Be 9 Be n-rich S.Pirrone EPJ Web of Conf. 17 (2011) G.Politi et al 2011 EPJ Web of Conf. 21 (2012) n-poor PRELIMINARY

25 Staggering effects 112Sn + 58Ni E/A = 35 MeV Chimera data Even-odd staggering in charge distribution Centrality No centrality dependence observed: final decays dominate G. Casini et al., PRC (2012)

26 1+R(q) Y 12 (q) Femtoscopy Final-state interactions Deuteron-Alpha correlations ( ) SY coinc p 1, p 2 + Coincidence pairs 1+ R(q) = k Imaging: Profile of emitting SY evt.mixing ( p 1, p 2 ) sources space-time!images! ( ) ( ) q (MeV/c) SY coinc p 1, p 2 SY evt.mixing p 1, p 2 q = m v 1 - v 2 + Uncorrelated pairs Nuclear FSI: correlation at q=42 and 84 MeV/c 6 Li deuteron-alpha q (MeV/c) Coulomb FSI: anti-correlation at small q values High angular resolution required: E.V. Pagano, G. Verde et al. Low q and resonances

27 first prototypes (4 telescopes) Pre-amplifier boxes Si-Si matrix Si-CsI(Tl) matrix Preliminary results analysis underway Spring 2013: first experiments Farcos+Chimera

28 1+R(q) NN correlations and symmetry energy IBUU simulations 52 Ca+ 48 Ca E/A=80 MeV Central collisions Correlation functions neutron-neutron 7 Asy-soft 5 3 Asy-stiff proton-proton Lie-Wen Chen et al., PRL (2003), PRC(2005) 3 2 proton-neutron Proton/neutron emission times sensitive to density dependence of the symmetry energy 1 q (MeV/c)

29 Extensions to neutron detection Working group formed (L. Francalanza, A. Pagano et al.) Simulations and tests for integration into Chimera and Farcos telescopes just a schematic example: Electronics CsI(Tl) CsI(Tl) P under study DSSSD1 DSSSD2

30 Possible perspectives at Riken n-p, n-n and p-p correlations at E/A>300 MeV Detector for event characterization Nebula Outside user charged particle detectors Informal discussions G.V. and T. Nakamura

31 Non-femtoscopic correlations: particle decay spectroscopy Not only EoS 10 C* Expansion Several unbound species in just one single experiment! HIC and correlations as a spectroscopic tool Cluster states in stable and exotic nuclei BEC, Hoyle (A. Raduta et al., Phys. Lett. B705, 65, 2011) Branching ratios for exotic decays (sequential and multi-body breakup) F. Grenier et al., Nucl. Phys. A811 (2008) 233

32 Conclusions Probes of symmetry energy at high density: GSI energies: n/p flow π + /π- and K + /K 0 emission ratios: future perspectives at RIKEN (SAMURAI/TPC, ) Probes of symmetry energy at low density: Intermediate energies: Isospin diffusion and drift; range of symmetry energies (γ~ ) still large error bars Femtoscopy and neutron observables as a promising probe for future projects (both suband supra-saturation densities)

33 Acknowledgements All the Chimera, Exochim, Farcos groups Special acknowledgements to students and postdocs

34 one more word about symmetry and Mt. Tokyo asymmetry Mt. Catania

35 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 , 2013