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

Claudia Höhne China, November 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). → !

Claudia Höhne China, November Mapping the QCD phase diagram (II) → – 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 AGeV starting in 2015 [Andronic et al. Nucl. Phys. A 772, 167 (2006).

Claudia Höhne China, November 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.]

Claudia Höhne China, November Phase diagram [Bratkovskaya et al., PRC 69 (2004) ] 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: AGeV for Au+Au

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

Claudia Höhne China, November 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

Claudia Höhne China, November 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!

Claudia Höhne China, November Strangeness production deconfinement [NA49, C.Blume et al., nucl-ex/ ] 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!

Claudia Höhne China, November 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

Claudia Höhne China, November 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/ ] full energy dependence needed! central midcentral peripheral [NA49, PRC68, (2003)] deconfinement

Claudia Höhne China, November 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/ S. Das, SQM06]

Claudia Höhne China, November 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]

Claudia Höhne China, November 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, (2004) ]

Claudia Höhne China, November 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 !

Claudia Höhne China, November 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!

Claudia Höhne China, November 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