Results of the ASY-EOS experiment at GSI: The symmetry energy at - PowerPoint PPT Presentation

NSMAT2016: Results of the ASY-EOS experiment at GSI: The symmetry energy at suprasaturation density W. Trautmann GSI Helmholtzzentrum, Darmstadt, Germany

NSMAT2016: Results of the ASY-EOS experiment at GSI: The symmetry energy at suprasaturation density Russotto et al., PRC 94, 034608 (2016) FOPI-LAND UrQMD ASY-EOS Sensitivity to density Potential for future exp. W. Trautmann GSI Helmholtzzentrum, Darmstadt, Germany

Access to high density central Sn+Sn soft stiff soft stiff Bao-An Li, PRL 88 (2002): differential flows in heavy ion reactions Bao-An Li, NPA 708(2002)

elliptic flow/squeeze out UrQMD: Q. Li et al., PRC 89 (2014) Au+Au 400A MeV 0.05 0.25 < b 0 < 0.45 0.25 < b 0 < 0.45 FOPI protons 0 v 2 -0.05 asy-hard asy-h 0.05 p n Z=1 0 v 2 -0.05 asy-soft asy-s -1 0 1 with Plastic Ball at Bevalac: H.H. Gutbrod et al., PRC 42, 640 (1990) y 0 data: Reisdorf et al., NPA 876 (2012) for neutrons with FOPI-LAND at GSI: Y. Leifels et al., PRL 71, 963 (1993)

pressure gauge for neutron-star matter neutron-over-charged particle elliptic-flow ratio in neutron-rich systems analysis with transport UrQMD (Li & Bleicher) Tübingen QMD (Cozma) differential squeeze-out tested with FOPI-LAND data 197 Au + 197 Au @ 400 A MeV

pressure gauge for neutron-star matter neutron-over-charged particle elliptic-flow ratio in neutron-rich systems analysis with transport UrQMD (Li & Bleicher) Tübingen QMD (Cozma) tested with FOPI-LAND 197 Au + 197 Au @ 400 A MeV

FOPI-LAND experiment acceptance in p t vs. rapidity SB : shadow bar Forward Wall for for background centrality and measurement reaction-plane orientation beam SB L arge A rea N eutron D etector LAND 2 LAND 1 5 m neutron squeeze-out: main yield here Y. Leifels et al., PRL 71, 963 (1993)

FOPI-LAND experiment Forward Wall LAND 2x2x1m 3 iron/plastic ≈ 3 m diameter 700 plastic scintillator time-of-flight spectrometer elements measuring 400 channels energy loss and time thin plastic veto-wall

azimuthal angular distributions relative to the reconstructed reaction plane for neutrons , background subtracted near target rapidity mostly directed flow at mid-rapidity strong squeeze-out near projectile rapidity mostly directed flow fitted with Fourier expansion: f(∆φ)=a 0 *(1.0+2 v 1 *cos(∆φ)+2 v 2 *cos(2∆φ)) ∆φ = φ particle – φ reaction plane ratios compared to UrQMD model predictions Q. Li et al., J. Phys. G 31(2005); 32 (2006) 2 π 0 ∆φ

results from FOPI/LAND experiment γ =1.5 linear γ =0.5 neutron/hydrogen FP1: γ = 1.01 ± 0.21 FP2: γ = 0.98 ± 0.35 neutron/proton FP1: γ = 0.99 ± 0.28 FP2: γ = 0.85 ± 0.47 adopted: γ = 0.9 ± 0.4 FPx: parametrizations of N-N Xsections small effects on ratios

the symmetry energy from nuclear many-body theory pot in UrQMD E A (ρ,δ) = E A (ρ,0) + E sym (ρ) ∙ δ 2 + O(δ 4 ) parametrization of E sym δ = (ρ n –ρ p )/ρ γ =1.5 E sym (ρ) pot (MeV) linear (APR) E sym γ =0.5 supersoft Fuchs and Wolter, ρ/ρ 0 EPJA 30 (2006) E sym = E sym pot +E sym kin = 22 MeV·(ρ/ρ 0 ) γ +12 MeV·(ρ/ρ 0 ) 2/3

result of FOPI-LAND analysis pot in UrQMD E A (ρ,δ) = E A (ρ,0) + E sym (ρ) ∙ δ 2 + O(δ 4 ) parametrization of E sym δ = (ρ n –ρ p )/ρ γ =1.5 E sym (ρ) pot (MeV) FOPI-LAND linear (APR) E sym γ =0.5 supersoft Fuchs and Wolter, ρ/ρ 0 EPJA 30 (2006) E sym = E sym pot +E sym kin = 22 MeV·(ρ/ρ 0 ) γ +12 MeV·(ρ/ρ 0 ) 2/3 updates and model studies: Trautmann and Wolter, IJMPE 21 (2012) Cozma et al., PRC 88, 044912 (2013) γ = 0.9 ± 0.4 Russotto et al., EPJA (2014) 50:38 Russotto et al., PLB 697 (2011) 471 Y. Wang et al., PRC 89, 044603 (2014)

systematic parameter test with Tübingen QMD*) from M.D. Cozma et al., PRC 88 (2013) steps towards model invariance: Cozma et al. tested in UrQMD: Russotto et al. FP1 vs. FP2, i.e. momentum dep. of NNECS 400A MeV tested in T-QMD: soft vs. hard 190<K<280 MeV soft (x=1) density dependence of NNECS asymmetry dependence of NNECS wave packet 2.5<L<7.0 fm 2 optical potential momentum dep. of isovector potential conclusion : robust observable super-soft not compatible with FOPI- LAND data statistics insufficient => ASY-EOS *) V.S. Uma Maheswari, C. Fuchs, Amand Faessler, L. Sehn, D.S. Kosov, Z. Wang, NPA 628 (1998)

Asy-Eos experiment S394 in May 2011 CHIMERA, ALADIN Tof-wall, µ-ball, for impact parameter orientation and modulus studied reactions: 197 Au + 197 Au @ 400 A MeV 96 Ru + 96 Ru @ 400 A MeV 96 Zr + 96 Zr @ 400 A MeV Constraining the Symmetry Energy at Supra-Saturation Densities with Measurements of Neutron and Proton Elliptic Flows Co-Spokespersons: R.C. Lemmon and P. Russotto

Laboratori Nazionali del Sud 4 double rings of CHIMERA, LNS Catania Catania, Sicilia 3,8 m

93 authors from 14 countries spokespersons: P. Russotto (Catania) R.C. Lemmon (Daresbury)

93 authors from 14 countries recent analysis: Yongjia Wang (Huzhou) Dan Cozma (Bukarest)

coverage 1.2 4 10 1.0 0.8 3 10 t β 0.6 γ LAND 2 10 0.4 MicroBall 10 CHIMERA 0.2 AToF c.m. Proj 0.0 1 0.4 0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 − − y lab P . Russotto et al., PRC 94, 034608 (2016)

flow ratio vs transverse momentum 1.3 1.2 =0.75 0.10 γ ± 1.1 γ =1.5 1 ch stiff 2 0.9 /v 0.8 n 2 γ =0.5 v 0.7 0.6 soft 0.5 0.4 0.3 0.4 0.5 0.6 0.7 p /A (GeV/c) t P . Russotto et al., PRC 94, 034608 (2016)

from acceptance-integrated flow ratios L=72±13 MeV FOPI-LAND: Russotto et al. PLB 697 (2011) P . Russotto et al., PRC 94, 034608 (2016)

"A way forward in the study of the symmetry energy ..." Horowitz et al., JPhG 41 (2014) following NUSYM13 maximum sensitivity of structure data near 2/3 ρ 0 Zhang and Chen (PLB 726 (2013)) use Skyrme-Hartree-Fock to analyze isotope binding energy difference and neutron skin thickness of Sn isotopes; B.A. Brown (PRL 111 (2013)) uses Skyrme, properties of doubly-magic nuclei (binding energies, rms charge radii, and single-particle energies) and ∆r np =0.16 – 0.24 fm for 208 Pb.

with E sym (ρ 0 ) = 31 MeV 80 Brown n/ch flow Zhang HIC Sn+Sn 60 L E sym (MeV) IAS FOPI-LAND ASY-EOS 40 L=63±11 MeV 20 0 0 0.5 1 1.5 2 ρ / ρ 0 E sym (ρ 0 ) (MeV) Lattimer & Steiner, FOPI-LAND: Russotto et al. PLB 697 (2011) EPJA 50 (2014) P . Russotto et al., PRC 94, 034608 (2016)

sensitivity to density of elliptic-flow ratio for Au+Au @ 400 AMeV Dan Cozma et al. Tübingen QMD and force developed by Das, Das Gupta, Gale, and Bao-An Li, Phys. Rev. C 67 (2003) 034611

sensitivity to density of elliptic-flow ratio for Au+Au @ 400 AMeV Dan Cozma et al. calculate DEFR (ρ) ρ D ifference of E lliptic- F low R atio Tübingen QMD and force developed by Das, Das Gupta, Gale, and Bao-An Li, Phys. Rev. C 67 (2003) 034611

sensitivity to density D ifference of E lliptic- F low R atio 0.5 (n,ch) 0.25 DEFR ρ 0.0 n/p 0.75 n/H Sensitivity n/ch 0.5 0.25 Tübingen QMD and force developed by Das, Das Gupta, Gale, and Bao-An Li, 0.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Phys. Rev. C 67 (2003) 034611 / 0 P . Russotto et al., PRC 94, 034608 (2016)

symmetry pressure p 0 = 3.8 ± 0.7 MeV/fm 3 neutron star pressure p 0 = 3.4 ± 0.7 MeV/fm 3 ρ 0 Steiner, Lattimer, and Brown, ApJ 765, L5 (2013)

opportunities Le Fèvre et al., NPA 945 (2016) Au+Au „ force-weighted“ density „ force-weighted“ density graphics by Arnaud Le Fèvre 27

opportunities Le Fèvre et al., NPA 945 (2016) Paolo Russotto, UrQMD (2016) <ρ> ≃ 2ρ 0 <ρ> ≃ 2ρ 0 within reach with Au+Au@1000 within reach with Au+Au@1000 graphics by Arnaud Le Fèvre 28

summary and outlook • high-densities probed in reactions at SIS energies; γ pot = 0.9 ± 0.4 from FOPI-LAND (2011); γ pot = 0.72 ± 0.19 from ASY-EOS (2016) • L= 72 ± 13 MeV from ASY-EOS (2016); super-soft and super-stiff ruled out • studies of model invariance performed; Dan Cozma et al., PRC 88, 044912 (2013) • elliptic flow unique regarding the sensitivity to density < ρ > ≃ 2 ρ 0 within reach with SIS/FAIR beams • • theoretical issues: BUU consistent with QMD short-range correlations and clustering in transport pion production in transport

backups

model dependence Wenmei Guo et al., PLB 738, 197 (2014) elliptic flow ratio pion ratios

short-range correlations soft super-soft Gao-Chan Yong, Phys. Rev. C 93, 044610 (2016)

short-range correlations modifies flow difference by <½ % Zhang and Yong, arXiv:1605.03656

L vs flow ratio or difference Yongjia Wang et al., Phys. Rev. C 93, 044610 (2016)

systematic parameter test with Tübingen QMD*) elliptic flow difference, Au+Au @ 400 M.D. Cozma et al., PRC 88, 044912 (2013) 0.02 steps towards model invariance: 0.01 tested in UrQMD: n-p FP1 vs. FP2, 0.0 v 2 i.e. momentum dep. of NNECS tested in T-QMD: -0.01 soft vs. hard 190<K<280 MeV Cugnon Li-Machleidt density dependence of NNECS K+L+V opt +S K+L asymmetry dependence of NNECS V opt +S -0.02 wave packet 2.5<L<7.0 fm 2 -2 -1 0 1 2 optical potential x superstiff supersoft momentum dep. of isovector potential conclusion : super-soft not compatible with FOPI-LAND data *) V.S. Uma Maheswari, C. Fuchs, Amand Faessler, L. Sehn, D.S. Kosov, Z. Wang, NPA 628 (1998)