The Physics of Dense Nuclear Matter

1. The Physics of Dense Nuclear Matter Introduction StatusNear future Perspectives at FAIR Joachim Stroth Univ. Frankfurt / GSI

2. Dense nuclear matter in the laboratory First chance collisions Dense matter Freeze-out What are the properties of dense nuclear matter? Its macroscopic properties depend on the microscopic structure! → Hadron physics (in-medium) Joachim Stroth

3. The physics case J. Wambach et al. Matter properties (EOS) of compact stars! • Does the quark model provide the right description of hadrons? • What is the relevant excitation spectrum as the matter density increases? • What is the role of chiral symmetry breaking in the generation of hadron masses? • Where are the limits of hadronic existence? Joachim Stroth

4. Pionic atoms Mesonic Atoms • Experiments combine techniques from hadron and heavy ion physics.(inelastic NN reaction and pick-up). • Pions with favorable momentum are trapped in the Coulomb-field of the heavy Nucleus. • Pionic bound states are clearly observed. • The measured binding energies evidence a reduced expectation value of the Chiral Condensate at nuclear ground state density. Fragment separator at GSI used as high-resolution forward spectrometer • Collaboration • Nava, GSI, Munich, Jülich, Tokyo, Niigata, RIKEN Joachim Stroth

5. In-medium mass of strange mesons K+ Ni+Ni @ 1.93 AGeV central collisions K- M. Menzel et al., KaoS Collab., Phys. Lett. B 495 (2000) 26 K. Wisniewski et al., FOPI Collab., Eur. Phys. J A 9 (2000) 515Transport calculations: G.Q. Li & G.E. Brown KAOS results selected among the 10 most important physics results in 1998 (APS) In-medium potential of strange mesons should lead to shift a of the effective kaon mass! Indication observed in heavy ion reaction at the SIS18, GSI by KAOS and FOPI. Joachim Stroth

6. Kaonic bound states Exotic bound states with strangeness • Attractive K- N potential results in additional binding • Production mechanisms presently uncertain, might be populated in HI collisions but probably also in p induced reactions. Joachim Stroth

7. HADESHigh Acceptance Dielectron Spectrometer 12C+ 12C 2 AGeV e+ 208Pb -  n preliminary e- Low-mass vector mesons • Detected by electron pair reconstruction (penetrating probes). • Spectrometer with high invariant mass resolution and high rate capability. • operational since 2001 at GSI. • Beams of: • Pions • Protons • Nuclei Joachim Stroth

8. International FAIR Project: SIS300 • Key Technical Features • Cooled beams • Rapidly cycling superconducting magnets Primary Beams • 1012/spill; 1.5-2 GeV/u; 238U28+ • Factor 100-1000 over present in intensity • 2(4)x1013/spill 30 GeV protons • 1010/spill 238U73+ up to 35 GeV/u • up to 90 GeV protons SIS 100/300 Secondary Beams SIS UNILAC • Broad range of radioactive beams up to1.5 - 2 GeV/u; up to factor 10 000 in intensity over present • Antiprotons 3 - 30 GeV CBM Storage and Cooler Rings • Radioactive beams • e- – A (or Antiproton-A) collider • stored and cooled 0.8 - 14.5GeV antiprotons Joachim Stroth

9. The energy scan at SPS (NA94) Exiting observations at an energy of around 30 AGeV • Relative enhancement of strangeness • Not explained by transport calculationsand statistical model SPS heavy ion program suspended due to priority for LHC CERN SPS-C: "The search for the critical point is of high importance for the understanding of QCD. .... Respective proposals can be accepted for a time period after 2008". Integrated Luminosity ? NA49, M. Gazdzicki et al. Fluctuations due to approach of the critical point ?? Joachim Stroth

10. The Compressed Baryonic Matter program Experimental goal of the CBM collaboration: Systematic investigation of dense baryonic matter using penetrating and rare probes! Heavy ion collisions at interaction rates of up to 107 Hz Excitation functions from 2 to 35 GeV/u Needs large integrated luminosity: High beam intensity and duty cycle, available for several month per year CBM Detector HADES Observables: Penetrating probes: , , , J/ Strangeness: K, , , , , Open charm: Do, D Hadrons ( p, π), exotica Joachim Stroth

11. Physics program of CBM SIS18 SIS300 • Fluctuations in the strangeness production • Signal for the critical point • Low mass electron pairs • Probe the in-medium structure of hadrons • Near threshold open-charm production • Analogy to strangeness at 1-2- AGeV • Charmonium production • Sensitive to the early state of the matter Joachim Stroth

12. The physics community FOPI upgrade → heavy ion program world-wide unique European collaboration + Japan: 50 physicist Bucharest, Budapest, Clermont-Ferrand, Darmstadt, Dresden, Florence, Heidelberg, Moscow, Seoul, Strasbourg, Warszawa, Zagreb HADES →heavy ions world-wide unique (elementary JLAB, KEK) European collaboration: 120 physicist Bratislava, Catania, Dubna, Frankfurt, Giessen, Milano, Moscow, Garching, Nicosia, Orsay, Rez, Dresden, Santiago de Compostela, Valencia CBM →RHIC low energy program uncertain, SPS suspended International collaboration: >300 physicistFurther interest by people from former NA49 experiment – CERN proposal ? Theory →Microscopic transport essential Smaller groups at different universities FP6 I3HP FP6 I3HP FP6 I3HP Joachim Stroth

13. Motivation: II „The challenge for the next century physics is: explain confinement and broken (chiral) symmetry“T.D. Lee „But perhaps the most interesting and surprising thing about QCD at high density is that, by thinking about it, one discoversa fruitful new perspective on the traditional problem of confinement and chiral-symmetry breaking”.F. Wilczek Joachim Stroth