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ASY-EOS Past and future: PR Milano, 28/04/14

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Fuchs and Wolter, EPJA 30 (2006) EOS of symmetric nuclear and neutron matter from Ab initio calculations (red) and phenomenological approaches E bind (MeV) E sym E Sym (MeV) Symmetry Energy

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Qingfeng Li, J. Phys. G31 1359-1374 (2005) P.Russotto et al., Phys. Lett. B 697 (2011) UrQMD :Au+Au @ 400 AMeV 5.5

LAND+VETO TOFWALL Krakow array Beam Line Ball Target Chimera Start detector Shadow bars Ball: 4 rings CsI(Tl), >60. Discriminate real target vs. air interactions at backward angles. Multiplicity measurements. Shadow bar: evaluation of background neutrons in LAND LAND: Large Area Neutron Detector. Plastic scintillators sandwiched with Fe 2x2x1 m 3 plus plastic veto wall. New Taquila front-end electronics. Neutrons and Hydrogen detection. Flow measurements TOFWALL: 96 plastic bars Tof, Energy X-Y position. Trigger, impact parameter and reaction plane determination Kracow array: 35 (5x7) triple telescopes (Si-CsI- CsI) placed at 21

Reaction plane orientation Au+Au @ 400 AMeV g40_23092013 for Yc.m.>0.1 J-Y Ollitrault arXiv:nucl-ex/9711003v2 b selection (deg) b>7.5 fm1.010.3634 3

N/Z of high density regions sensitive to E sym () High > 0 : asy-stiff more repulsive on neutrons stiffness B.A. Li et al., PRC71 (2005) Which densities can be explored in the early stage of the reaction ? Bao-An Li, NPA 708 (2002) High density symmetry energy in relativistic heavy ion collisions

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IBUU04 ImIQMD E sym at high density: - / + ratio Z. Xiao et al., PRL 102 (09) Z.Q. Feng, PLB 683 (2010) Ferini, at al., NPA 762 (2005) NL NL NL W.J. Xie, at al., PLB 718 (2013) RMF ImIBL

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1230 E sym (MeV) 1 1 2 (measured by FOPI, for different systems and energies, as compared to different models) Results model dependent Density dependence of symmetry energy unambiguously soft or hard BUT symmetry energy n/p ratio, number of nn, np, pp collisions medium effective masses (N ), cross sections thresholds Interpretation of pion data not straight forward Kaons: more sensitive probes? Higher thresholds Weakly interacting in medium Freeze-out already at 20 fm/c See: Z. Xiao et al., PRL 102 (09) IBUU04 Z.Q. Feng, PLB 683 (2010) ImIQMD W.J. Xie, at al., PLB 718 (2013) ImIBL G. Ferini, at al., NPA 762 (2005) RMF E sym at high density: - / + ratio

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UrQMD: momentum dep. of isoscalar field momentum dep. of NNECS momentum independent power-law parameterization of the symmetry energy Tbingen-QMD: density dep. of NNECS asymmetry dep. of NNECS soft vs. hard EoS width of wave packets momentum dependent (Gogny inspired) parameterization of the symmetry energy M.D. Cozma, PLB 700, 139 (2011); arXiv:1102.2728 Results with Tbingen QMD Au+Au 400 A MeV b< 7.5 fm stiffnes M.D. Cozma et al., Towards a model-independent constraint of the high-density dependence of the symmetry energy, arXiv:1305.5417arXiv:1305.5417 [nucl-th] PRC88 044912 (2013) x =-1.351.25

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Why 132 Sn?

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Au+Au @ 400 AMeV b< 7.5 fm L=769