1. Physics with CBM Claudia Höhne, GSI Darmstadt CBM collaboration Outline motivation, physics case observables

2. Claudia Höhne China, November 20062 Mapping the QCD phase diagram What do we know from theory? → Predictions from lattice QCD: crossover transition from partonic to hadronic matter at small  B and high T, T c (  B =0) = 151 – 192 MeV critical endpoint in intermediate range of the phase diagram (current estimates  B = 300 – 700 MeV, T ≈ 140 – 160 MeV) first order deconfinement phase transition at high  B but moderate T What do we know from experiment? → Heavy-ion collisions: chemical freeze-out curve from final hadron yields measured in the experiments: T ≈ 160 MeV at top RHIC energy top SPS, RHIC (high T, low  B ): indications for relevance of partonic degrees of freedom lower SPS, AGS (intermediate T-  B range): intriguing observations around 30 AGeV beam energy [Andronic et al. Nucl. Phys. A 772, 167 (2006). → CBM@FAIR !

3. Claudia Höhne China, November 20063 Mapping the QCD phase diagram (II) → CBM@FAIR – high  B, moderate T: searching for the landmarks of the QCD phase diagram first order deconfinement phase transition chiral phase transition QCD critical endpoint in A+A collisions from 10-45 AGeV starting in 2015 [Andronic et al. Nucl. Phys. A 772, 167 (2006).

4. Claudia Höhne China, November 20064 Dense baryonic matter baryon density in central cell (Au+Au, b=0 fm) in transport calculations HSD (mean field, hadrons + resonances + strings), QGSM similar results enormous energy and baryon densities reached! (  >  crit ) [CBM physics group, C. Fuchs, E. Bratkovskaya priv. com.]

5. Claudia Höhne China, November 20065 Phase diagram [Bratkovskaya et al., PRC 69 (2004) 054907] UrQMD calculation of T,  B as function of reaction time (open symbols – nonequilibrium, full symbols – appr. pressure equilibrium) phase border crossed already at rather low energies (see also results from 3-fluid hydrodynamics) critical point in reach? CBM energy range: 15 - 35 AGeV for Au+Au

6. Claudia Höhne China, November 20066 High baryon density matter! [Rapp, Wambach, Adv. Nucl. Phys. 25 (2000) 1, hep-ph/9909229] [Mishra et al., PRC 69, 015202 (2004) ] hadronic properties should be effected by the enormous baryon densities which will be created (partial) restoration of chiral symmetry?  D

7. Claudia Höhne China, November 20067 Observables Goal of CBM experiment: comprehensive and systematic (energy, system size) studies of all relevant diagnostic probes including: hadrons, event-by-event fluctuations, correlations, collective flow multistrange hyperons low-mass vector mesons open charm (D 0, D ±,  c ) charmonium (J/ ,  ') [W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 753] CBM energy range rare probes! CBM energy range

8. Claudia Höhne China, November 20068 Observables (II) physics topics deconfinement at high  B ? softening of EOS ? order of phase transition ? Critical point ? in-medium properties of hadrons  onset of chiral symmetry restoration at high  B observables strangeness production: K,  charm production: J/ , D flow excitation function event-by-event fluctuations   e + e - open charm CBM: rare probes → high interaction rates!

9. Claudia Höhne China, November 20069 Strangeness production deconfinement [NA49, C.Blume et al., nucl-ex/0409008] s-production mechanism different in hadronic / partonic scenario maximum of strangeness production at 30 AGeV → change from hadronic to partonic phase? CBM energy range: 15 – 35/45 AGeV (depending on A) verify and extend energy dependence!

10. Claudia Höhne China, November 200610 J/  suppression screening of cc pairs in partonic phase anomalous J/  suppression observed at top-SPS and RHIC energies signal of deconfinement? energy dependence?! [E. Scomparin for NA 60, QM05] deconfinement

11. Claudia Höhne China, November 200611 collective flow collapse elliptic flow of protons at lower energies signal for first order phase transition?! [e.g. Stoecker, NPA 750 (2005) 121, E. Shuryak, hep-ph/0504048] full energy dependence needed! central midcentral peripheral [NA49, PRC68, 034903 (2003)] deconfinement

12. Claudia Höhne China, November 200612 K/  fluctuations Critical point dynamical fluctuations of the K/  ratio increase towards lower energies not reproduced by UrQMD: resonance contribution?  energy dependence needed for lower energies! [C.Roland et al., nucl-ex/0403035 S. Das, SQM06]

13. Claudia Höhne China, November 200613 modifications    → l + l - In medium within acceptance enhancement of low-mass dilepton pairs seen at low (2 AGeV, C+C) and high (158 AGeB, In+In) energies! → broadening of the  – meson intermediate energies with highest baryon densities? [R. Holzmann for HADES, QM05][E. Scomparin for NA 60, QM05]

14. Claudia Höhne China, November 200614 D-mesons [W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745] SIS18 SIS100/ 300 D-mesons sensitive to medium! In medium [Mishra et al., PRC 69, 015202 (2004) ]

15. Claudia Höhne China, November 200615 D-mesons (II) [E. Bratkovskaya, W. Cassing, private communication] In medium Dropping D-meson masses with increasing light quark density might give a large enhancement of the open charm yield at 25 A GeV !

16. Claudia Höhne China, November 200616 CBM – summary CBM offers a very interesting physics program exploring the QCD phase- diagram at highest baryon densities but still moderate temperatures unique features expected in CBM energy range: first order phase transition, critical point CBM as 2nd generation experiment will be able to study rare probes, fluctuations and correlations! exciting physics from ~2015 on!

17. Claudia Höhne China, November 200617 CBM collaboration Russia: IHEP Protvino INR Troitzk ITEP Moscow KRI, St. Petersburg China: CCNU Wuhan USTC Hefei Croatia: RBI, Zagreb Portugal: LIP Coimbra Romania: NIPNE Bucharest Poland: Krakow Univ. Warsaw Univ. Silesia Univ. Katowice Nucl. Phys. Inst. Krakow LIT, JINR Dubna MEPHI Moscow Obninsk State Univ. PNPI Gatchina SINP, Moscow State Univ. St. Petersburg Polytec. U. Ukraine: Shevchenko Univ., Kiev Cyprus: Nikosia Univ. Univ. Mannheim Univ. Münster FZ Rossendorf GSI Darmstadt Czech Republic: CAS, Rez Techn. Univ. Prague France: IPHC Strasbourg Germany: Univ. Heidelberg, Phys. Inst. Univ. HD, Kirchhoff Inst. Univ. Frankfurt Univ. Kaiserslautern Hungaria: KFKI Budapest Eötvös Univ. Budapest India: VECC Kolkata SAHA Kolkata IOP Bhubaneswar Univ. Chandigarh Univ. Varanasi IlT Kharagpur Korea: Korea Univ. Seoul Pusan National Univ. Norway: Univ. Bergen Kurchatov Inst. Moscow LHE, JINR Dubna LPP, JINR Dubna 46 institutions > 400 members Strasbourg, September 2006