Strange particles and neutron stars - experiments at GSI Outline: Probing dense baryonic matter (1-3 ρ 0 )  The nuclear equation-of-state  In medium properties of strange mesons Towards highest baryon densities (3-10 ρ 0 )  Exploring the phases of QCD matter Peter Senger (GSI) International Symposium on Heavy-Ion Physics, April 2-6, 2006, Frankfurt

Strongly interacting matter in neutron stars F. Weber J.Phys. G27 (2001) 465 nucleon star: kaon condensate “Strangeness" of dense matter ? In-medium properties of hadrons ? Nuclear matter equation of state ? Deconfinement at high baryon densities ? color superconductor ?

Kaon production in Au+Au collisions at 1 AGeV K + mesons probe high densities udsuds n dudu  uddudd susu  K+K+ uduudu  uuuu  udsuds susu p K-K- K - absorption

Idea: K + yield  baryon density ρ  compressibility κ Au+Au at 1 AGeV (RBUU): soft eos  ρ max  2.9 ρ 0  K + yield up hard eos  ρ max  2.4 ρ 0  K + yield down but: in C+C no influence of eos on K + yield ! Probing the nuclear equation-of-state at high density by K + meson production in C+C and Au+Au collisions C. Sturm et al., Phys. Rev. Lett. 86 (2001) 39

C. Fuchs et al., Phys.Rev.Lett. 86 (2001) 1974 QMD transport calculations

The compressibility of nuclear matter Experiment: C. Sturm et al., Phys. Rev. Lett. 86 (2001) 39 Theory: QMD C. Fuchs et al., Phys. Rev. Lett. 86 (2001) 1974 IQMD Ch. Hartnack, J. Aichelin, J. Phys. G 28 (2002) 1649 soft equation-of-state:  = 200 MeV Figure by C. Fuchs

K mesons in dense matter G.E Brown, C.H. Lee, M. Rho, V. Thorsson, Nucl. Phys. A 567 (1994) 937 T. Waas, N. Kaiser, W. Weise, Phys. Lett. B 379 (1996) 34 J. Schaffner-Bielich, J. Bondorf, I. Mishustin, Nucl. Phys. A 625 (1997) M. Lutz, C. Korpa, Nucl. Phys. A 700 (2002) 309 self-consistent coupled channel calculation (s,p,d waves) In-medium spectral functions of K -,  (1405) and  (1385)  (1405) K-K- K-K- N -1

In-medium modifications of K + mesons Data: M. Menzel et al., KaoS Collab., Phys. Lett. B 495 (2000) 26 K. Wisniewski et al., FOPI Collab., Eur. Phys. J A 9 (2000) 515 Figure by C. Fuchs

Data: Y. Shin et al., Phys. Rev. Lett. 81 (1998) 1576 F. Uhlig et al., Phys.Rev.Lett. 95 (2005) Theory: A. Larionov, U. Mosel, nucl-th/ Evidence for repulsive K + N interaction ! K + azimuthal emission pattern from A+A collisions

F. Uhlig et al., Phys. Rev. Lett. 95 (2005) Ni+Ni at 1.93 AGeV: π, K + and K - azimuthal distributions 3.8 fm < b < 6.4 fm 0.4 < y/y beam < GeV < p ┴ < 0.8 GeV IQMD Calculation: C. Hartnack et al.

dN(φ)/φ  1 + 2v 1 cos(φ) + 2v 2 cos(2φ) +... Au+Au 1.5 AGeV semi-central collisions (b > 6.4 fm) K + and K - azimuthal angular distributions M. Płoskon, PhD Thesis 2005

dN(φ)/φ  1 + 2v 1 cos(φ) + 2v 2 cos(2φ) +... Elliptic flow of K + and K - mesons: Comparison to off-shell transport calculations and in-medium spectral functions Data: M. Płoskon, PhD Thesis, Univ. Frankfurt 2005 Off-shell transport calculations: W. Cassing et al., NPA 727 (2003) 59, E. Bratkovskaya, priv. com. Coupled channel G-Matrix approach (K- spectral functions): L. Tolos et al., NPA 690 (2001) 547

The Kaon Spectrometer at SIS (1991 – 2002) Collaboration GSI Darmstadt: P. Koczoń, F. Laue, M. Płoskon, E. Schwab, P Senger, C. Sturm TU Darmstadt: A. Förster, S. Lang, H. Oeschler, A. Schmah, F. Uhlig Univ. Frankfurt: Y. Shin, T. Schuck, H. Ströbele Univ. Marburg: I. Böttcher, B. Kohlmeyer, M. Menzel Univ. Kraków: M. Dębowski, G. Surówka, W. Waluś FZ Rossendorf: F. Dohrmann, E. Grosse, L. Naumann, W. Scheinast, W. Wagner

Towards higher baryonic densities Ch. Fuchs, Tübingen

Baryon density in central cell (Au+Au, b=0 fm): QGSM: Cascade, hadrons + resonances + strings Transport calculations: baryon and energy densities C. Fuchs, V. Toneev

“Trajectories” from UrQMD H. Stöcker nucl-th/

“Trajectories” from 3 fluid hydrodynamics Hadron gas EOS: Y. Ivanov, V. Russkikh, V.Toneev nucl-th/ early phase (first 2 fm/c) not in thermodynamic equilibrium !

Intriguing observations by CERN-SPS coexistence phase hadrons QGPQGP critical point next steps:  confirmation of NA49 → Low energy run at RHIC ?  comprehensive experimental study → FAIR ? Pb+Pb

Diagnostic probes of compressed baryonic matter U+U 23 AGeV

Compressed Baryonic Matter: physics topics and observables Search for chiral symmetry restoration at high  B  in-medium modifications of hadrons Observables: , ,   e + e -, open charm,..... Search for a deconfined phase at high  B  enhanced strangeness production ? Observables: K, , , ,   anomalous charmonium suppression ? Observables: charmonium (J/ψ, ψ'), open charm (D 0, D  ) Probing the equation-of-state at high  B Observables: collective flow of hadrons, particle production at threshold energies (open charm) Search for the 1. order phase transition & the critical endpoint Observable: event-by-event fluctuations (K/π, p T,...)

Observables: Penetrating probes: , , , J /  → e+e- (μ+μ-) Strangeness: K, , , , , Open charm: D o, D , D s,  c, global features: collective flow, fluctuations,..., exotica Experimental program of CBM: Systematic investigations: A+A collisions from 8 to 45 (35) AGeV, Z/A=0.5 (0.4) p+A collisions from 8 to 90 GeV p+p collisions from 8 to 90 GeV Beam energies up to 8 AGeV: HADES Large integrated luminosity: High beam intensity and duty cycle, Available for several month per year Detector requirements Large geometrical acceptance (azimuthal symmetry !) good hadron and electron identification excellent vertex resolution high rate capability of detectors, FEE and DAQ

SIS18 SIS100/ 300 Meson production in central Au+Au collisions W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745

 Radiation hard Silicon (pixel/strip) Tracking System in a magnetic dipole field  Electron detectors: RICH & TRD & ECAL: pion suppression better 10 4  Hadron identification: TOF-RPC  Measurement of photons, π, η, and muons: electromagn. calorimeter (ECAL)  High speed data acquisition and trigger system The CBM Experiment Silicon Tracking System (STS)

Experimental challenges  10 7 Au+Au reactions/sec (beam intensities up to 10 9 ions/sec, 1 % interaction target)  determination of (displaced) vertices with high resolution (  50  m)  identification of electrons and hadrons Central Au+Au collision at 25 AGeV: URQMD + GEANT4 160 p, 400  -, 400  +, 44 K +, 13 K -,....

HADES 2 – 8 AGeV CBM 8 – 45 AGeV and outlook

CBM Collaboration : 40 institutions, > 350 Members Croatia: RBI, Zagreb China: Wuhan Univ. Hefei Univ. Cyprus: Nikosia Univ. Czech Republic: CAS, Rez Techn. Univ. Prague France: IReS Strasbourg Hungaria: KFKI Budapest Eötvös Univ. Budapest India: VECC Kolkata Romania: NIPNE Bucharest Russia: IHEP Protvino INR Troitzk ITEP Moscow KRI, St. Petersburg Kurchatov Inst., Moscow LHE, JINR Dubna LPP, JINR Dubna LIT, JINR Dubna MEPHI Moscow Obninsk State Univ. PNPI Gatchina SINP, Moscow State Univ. St. Petersburg Polytec. U. Ukraine: Shevshenko Univ., Kiev Korea: Korea Univ. Seoul Pusan National Univ. Norway: Univ. Bergen Germany: Univ. Heidelberg, Phys. Inst. Univ. HD, Kirchhoff Inst. Univ. Frankfurt Univ. Kaiserslautern Univ. Mannheim Univ. Münster FZ Rossendorf GSI Darmstadt Poland: Krakow Univ. Warsaw Univ. Silesia Univ. Katowice Portugal: LIP Coimbra

Summary Probing dense baryonic matter (1-3 ρ 0 ): Excitation function of K + production in A+A collisions:  The nuclear matter equation-of-state is soft ( K  200 MeV) Yield and elliptic flow of K + mesons:  The in-medium potential of K+ mesons is repulsive Yield and elliptic flow of K - mesons:  Quantitative interpretation of data requires off-shell transport calculations and in-medium spectral functions Towards highest baryon densities (3-10 ρ 0 ): Search for: first order phase transition critical endpoint chiral symmetry restoration Probes: strangeness, charm, vector mesons, flow, correlations, fluctuations,..... Comprehensive studies with Complementary to RHIC and ALICE and outlook

SIS100/ 300 Theoretical prediction of meson production in central Au+Au collisions Hadron String Dynamics transport calculation W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745

Track reconstruction: realistic magnetic field, 7 pixel detectors (no strips yet), no particle ID required D + mesons from Au+Au collisions at 25 AGeV D + production cross section from HSD 25 AGeV Au+Au from UrQMD D + mesons registered in min. bias Au+Au collisions at 25 AGeV → 1 day run with fast and rad hard vertex detector and tracking trigger → 100 days run with todays MAPS vertex detector without trigger

In-medium modification of D-mesons E. Bratkovskaya, W. Cassing

Extreme states of strongly interacting matter baryons hadrons partons Compression + heating = quark-gluon matter (pion production) Neutron stars Early universe

Off-shell transport calculations off-shell HSD: W. Cassing et al., NPA 727 (2003) 59 L. Tolos et al., NPA 690 (2001) 547 coupled channel G-Matrix approach: K - spectral functions

Critical endpoint: Z. Fodor, S. Katz, hep-lat/ S. Ejiri et al., hep-lat/ μ B <  400 MeV: crossover ε =0.5 GeV/fm 3 first order phase transition baryon density:  B  4 ( mT/2  ) 3/2 x [exp((  B -m)/T) - exp((-  B -m)/T)] baryons - antibaryons SIS300 SIS18 SPS RHIC LHC Mapping the QCD phase diagram with heavy-ion collisions lattice QCD crossover transition