Construct an EOS for use in astrophysics: neutron stars and supernovae wide parameter range:

1. Main points: • Constructan EOS for use in astrophysics: neutron stars and supernovae • wide parameter range: • proton fraction • Large charge asymmetry: thus investigation of symmetry energy • include light cluster correlations at low density taking into account medium dependence • Consistent with experimental results from heavy ion collisions • constitutes a unified approach for the EOS for a very wide range of densities and temperatures in collaboration with: Stefan Typel, GSI,Darmstadt and Techn. Univ. Munich, Germany Gerd Röpke, Univ. Rostock, Germany David Blaschke, Th. Klähn, Univ. Wroclaw, Poland J.B. Natowitz, A. Bonasera, S. Kowalsky, S. Shlomo, et al., Texas A&M, College Station, Tx, USA

2. EOS for astrophysical processes: wide range of conditions: global approach needed! Low densities: 2-, 3-,..many body correlations important. Bound states as new particle species. Change of composition and thermodyn- properties High densities (around saturation): homogeneous nuclear matter, mean field dominates In between: Liquid-gas phase transition at low temperatures, Inhomogeneous phases (lattice structures)  Approach necessary, that interpolates reliably commonly used EOS‘s: Lattimer-Swesty, NPA 535 (1991): Skyrme-type model, Liquid Drop modelling of finite nuclei embedded in nucleon gas Shen, Toki et al., Prog. Theor. Phys. 100 (1998): RMF model (TM1), a-particle with excluded volume procedure Horowitz, Schwenk, NPA776 (2006): virial expansion, n,p, a‘s, using experimental information on bound states and phase shifts: exact limit for low density • improvements: (S.Typel, G. Röpke, et al., PRC 2010, arxiv 0908:2344) • medium effects on light clusters, quantum statistical approach • realistic description of high density matter (DD-RMF)

3. Light clusters :Theoretical approaches: Nuclear Statistical Equilibrium (NSE): Mixture of ideal gases for each species (zero density limit) Virial expansion, expansion of in powers of fugacities Beth-Uhlenbeck, Physica 3 (1936) interactions included Energies and phase shifts from experiment: Horowitz-Schwenk, model independent, but only valid at very low densities, no medium dependence Thermodynamical GF approach (M. Schmidt, G. Röpke, H. Schulz, Ann. Phys. 202 (1990) self energy shifts, blocking effects (melting at Mott density), proper statistics , Ek(P,T,m), and generalized phase shifts Parametrization in density and temperature Needs quasiparticle energies  generalized mean field model

4. Lagrangian DD : density dependent RMF, S. Typel, PRC71 (2005) mass shifts of the clusters nucleon self energies with „rearrangement terms“ coupling of nucleons to clusters from density dependent coupling Generalized Relativistic Mean Field Model with Light Clusters Unified approach for nucleon and light cluster degrees of freedom degrees of freedom: fermions bosons mesons

5. Global approach from very low to high densities Summary of theoretical approach: • Quantumstatistical model (QS) • Includes medium modification of clusters (Mott transition) • Includes correlations in the continuum (phase shifts) • needs good model for quasi-particle energies in the mean field • In principle also possible for heavier clusters • Generalized Rel. Mean Field model (RMF) • Good description of higher density phase, i.e. quasiparticle energies • Includes cluster degrees of freedom with parametrized density and temperature dependent binding energies • no correlation in the continuum • Heavier clusters treated in Wigner-Seitz cell approximation (single nucleus approximation) S.Typel, G. Röpke, et al., PRC 2010, arxiv 0908:2344

6. Comparison to other approaches: alpha particle fractions Schwenk-Horowitz (black dash-dot; virial expansion with experimental BE and phase shifts for nucleons and alpha): exact for n0, but no disappearance of clusters for higher densities Nuclear Statistical Equilibrium (NSE) (green, dotted): decrease at higher densities because of heavier nuclei, but no medium modifications (melting) Shen-Toki (blue, dashed; RMF for p,n, heavy nuclei in Wigner-Seitz approximation in a gas of p,n,a, excluded volume method): medium modifications empirical, a survive very long Generalized RMF (red, solid: coupled RMF approach for p,n,d,t,h,a, medium dep. BE from QS approach, no heavy nuclei): strong deuteron correlations suppress alpha at higher densities Quantum Statistical (orange, dashed; medium modified clusters consistently in cluding scattering contributions): increases a fraction

7. Calculation in RMF of heavy cluster in Wigner-Seitz cell in beta-equilibrium T=5 MeV, b=0.3 Heavier clusters (nuclei) in the medium: Our approach: QS+RMF Hempel, Schaffner-Bielich (arXiv 0911:4073): NSE , with excluded volume with procedure

8. Equation of state: pressure vs. density RMF QS • NSE (thin lines) low density limit but breaks down already at small densities • Differences between approaches: too strong cluster effects in RMF, additional minima in QS • Regions of instability: phase transitions between clusterized und homogeneous phases

9. Usually: but EA not quadratic for low temperatures with clusters. Thus use: Symmetry energy: with (solid) and without (dashed) clusters

10. Isoscaling coefficients aand b Can this be measured?? et al., • 64Zn+(92Mo,197Au) at 35 AMeV • Central collisions, reconstruction of fireball • Determination of thermodyn. conditions as fct of vsurf=vemission-vcoul • ~time of emission with specified conditions of density and temperature: • temperature: isotope temperatures, double ratios H-He • densities rp, rn, from yield ratios and bound clusters • Isoscaling analysis (B.Tsang, et al., ) • Free symmetry energy

11. Single nucleus approx. (Wigner-Seitz), RMF Quantum Statistical model , T=1,4,8 MeV) Parametrization of nuclear symmetry energy of different stiffness (momentum dependent Skyrme-type) (B.A. Li) Comparision of low-density symmetry energy to experiment: Fsym Esym J. Natowitz, G, Röoke, et al., nucl-th/0908.2344, subm. PRL

13. deuteron 3He proton triton alpha Particle Fractions Mott density: clusters melt, homogeneous p,n matter; here heavier nuclei (embedded into a gas) become important, not yet fully implemented very low density: p,n Increasing density: clusters arise: deuteron first, but then a dominates Dependence on temperature ( T=0(2)20 MeV ) symmetric matter (b=0) Thin lines: NSE, i.e. without medium modifications of clusters (melting at finite densities) S.Typel, G. Röpke, et al., PRC 2010, arxiv 0908:2344

14. Equation of State (RMF): With (solid) and without (dashed) clusters): reduction at low and increase at intermediate densities, increase of critical temperature Maxwell construction for phase coexistence Coexistence region (left) and phase transition line(right) RMF w/o clusters (blue) RMF with clusters (red) QS (green)