Peter Senger (GSI)

1. Physics of High Baryon Densities - The CBM experiment at FAIR Peter Senger (GSI) Outline:  Exploring the QCD phase diagram  Physics questions and observables  CBM capabilities CBM Meeting /ROOTworkshop Jammu, Feb. 2008

2. Fundamental Questions of QCD  What is the equation-of-state of strongly interacting matter? (core collapse supernovae, neutron stars, early universe)  What is the structure of strongly interacting matter as a function of T and ρB ? (hot and dense hadronic medium, deconfined phase, phase transitions ?)  What are the in-medium properties of hadrons as a function of T and ρB ? (partial restoration of chiral symmetry ?) compression + heating = QGP ?

3. Super-dense matter in nature: neutron star Strange degrees of freedom ? In-medium properties of hadrons ? Compressibility of nuclear matter? Deconfinement at high baryon densities ? F. Weber J.Phys. G27 (2001) 465

4. The phase diagram of strongly interacting matter critical point hadrons Q G P coexistence phase Origin of hadron mass?

5. Exploring the QCD phase diagram picture from T. Hatsuda asymptotic freedom pre-formed pairs chiral symmetry restored crossover critical endpoint 1. order phase transition

6. TheQCD Phase diagram: facts and speculations Experimental results: Freeze-out curve (T, μB) Tfo = 1614 MeV at (μB=0) new state of matter = perfect liquid? L-QCD Predictions: TC= 151 ± 7 ± 4 MeV (Z. Fodor, arXiv:0712.2930 hep-lat) TC= 192 ± 7 ± 4 MeV (F. Karsch, arXiv:0711.0661 hep-lat) crossover transition at μB=0 (Z. Fodor, arXiv:0712.2930 hep-lat) 1. order phase transition with critical endpoint at μB > 0 High-energy heavy-ion collision experiments: RHIC, LHC: cross over transition, QGP at high T and low ρ Low-energy RHIC:search for QCD-CP with bulk observables NA61@SPS: search for QCD-CP with bulk observables CBM@FAIR: scan of the phase diagram with bulk and rare observables

7. Baryon and energy densities at FAIR energies Baryon/energy density in central cell (Au+Au, b=0 fm): Transport code HSD: mean field, hadrons + resonances + strings E. Bratkovskaya, W. Cassing

8. Net-baryon densities in central Au+Au collisions at FAIR: consistent picture from transport models Compilation by J. Randrup, CBM Physics Book, in preparation see also I.C. Arsene et al., Phys. Rev. C 75 (2007) 034902

9. Trajectories from Transport models UrQMD: L. Bravina et al. AMPT: C.M. Ko at CPOD 2007 FAIR beam energies:  A+A collisions up to 45 (35) AGeV, Z/A=0.5 (0.4)  p+p and p+A collisions up to 90 GeV

10. “Trajectories” from 3 fluid hydrodynamics Hadron gas EOS: Y. Ivanov, V. Russkikh, V.Toneev nucl-th/0503088

12. Messengers from the dense phase ? U+U 23 AGeV

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

14. Possible signatures of QGP in heavy-ion collisions transverse momentum e-by-e fluctuations volume high pt hadrons charm, strangeness heavy quarkonia mass and width of ρ,ω,φ antibaryons thermal photons and dileptons elliptic flow taken from the book: Quark-Gluon-Plasma: from big bang to little bang by Kohsuke Yagi, Tetsuo Hatsuda, Yasuo Miake (2006) adapted from an original by Shoji Nagamiya Seach for discontinuities in excitation functions of various observables ! How much are the signals diluted by finite size, short lifetimes, and hadronization ? εC εC Energy density

15. Discontinuity in strangeness production: signature for phase transition ? C. Blume et al. (NA49 at CERN-SPS), nucl-ex/0409008 Decrease of baryon-chemical potential: transition from baryon-dominated to meson-dominated matter ? Low energy run at RHIC: remeasurement of K/π (incl. e-by-e) CBM: Precise excitation function of multistrange particle production and propagation (collective flow)

16. Hadron elliptic flow at FAIR AMPT calculations: C.M. Ko at CPOD 2007 J/ψ, D, Λc ..?

17. Charm production Hadronic transport models: parameterization of measured cross sections O. Linnyk, E. Bratkovskaya, W. Cassing, H. Stöcker, Nucl. Phys. A786 (2007) 183 p-beam SIS300

18. The creation of charm via hard collisions (gg and qq) in the hadronic phase p u d u u d c Lc + u d d u d d D- n n c d D- c d c d D+ u d u d u u d u u p p p d d u n p u d u u d d n J/ψ c c u d u p d d u n

19. The creation of charm via hard collisions (gg and qq) in a partonic phase c c Formation of D mesons, charmed hyperons and charmonium via coalescence (e.g. statistical hadronization)

20. Charmonium and open charm production by statistical hadronisation in nuclear collisions A. Andronic, P. Braun-Munzinger, K. Redlich, J. Stachel, arXiv:0708.1488 1. c-cbar production in hard collisions, 2. statistical hadronization according to the temperature and the baryochemical potential

21. Charm production in partonic and hadronic matter Charmonium / open charm hadronic matter partonic matter Charmed particle ratios (ψ/D, Λc/D, D/Ds, ... ) are sensitive to the medium they are formed in

22. In-medium modifications of D mesons L. Grandchamp, R. Rapp and G. E. Brown, J.Phys. G30 (2004) S1355 A. Andronic, P. Braun-Munzinger, K. Redlich, J. Stachel, arXiv:0708.1488 Mass modifications of D mesons and charmed hyperons affect the ratios ψ'/ψ and charmonium to open charm

23. Probing chiral and deconfinement phase transitions with dilepton pairs Data: CERES Calculations: R. Rapp Data: NA60 In+In 158 AGeV

24. Charmonium dissociation in the quark-pluon plasma ? rescaled to 158 GeV J/ψ ψ' Quarkonium dissociation temperatures: (Digal, Karsch, Satz) Upper bounds on dissociation temperatures: A.Mocsy, P. Petreczky sequential dissociation of J/ψ and ψ'?  measure excitation functions of J/ψ, ψ', D, ΛC production in p+p, p+A and A+A collisions (incl. pT-spectra, flow)

25. Dilepton signal from the deconfined phase? Data: NA60 calculation: Renk & Ruppert QGP contribution ?

26. Inverse slope parameters of lepton pairs M < 1 GeV/c2: radial flow generated in the late hadronic phase M > 1 GeV/c2: messengers from the early partonic phase ?

27. hep-ph/0604269 no ρ,ω,φ→ e+e- (μ+μ-) data between 2 and 40 AGeV no J/ψ, ψ' → e+e- (μ+μ-) data below 160 AGeV needed: high statistics, excellent momentum resolution Searching for the modification of hadron properties via dilepton measurements Data: In+In 158 AGeV, NA60 Calculations: H.v. Hees, R. Rapp Data: CERES Calculations: R. Rapp

28. Summary: CBM physics topics andobservables The equation-of-state at high B  collective flow of hadrons  particle production at threshold energies (open charm?) Deconfinement phase transition at high B excitation function and flow of strangeness (K, , , , ) excitation function and flow of charm (J/ψ, ψ', D0, D, c) (e.g. melting of J/ψ and ψ') exitation function of low-mass lepton pairs QCD critical endpoint  excitation function of event-by-event fluctuations (K/π,...) Onset of chiral symmetry restoration at high B in-medium modifications of hadrons(,, e+e-(μ+μ-), D) CBM Physics Book in preparation

29. Experimental challenges Central Au+Au collision at 25 AGeV: URQMD + GEANT4 160 p 400 - 400 + 44 K+ 13 K-  up to 107 Au+Au reactions/sec  determination of (displaced) vertices with high resolution ( 50 m) identification of leptons and hadrons

30. The Compressed Baryonic Matter Experiment Transition Radiation Detectors Tracking Detector ECAL Muon detection System Resistive Plate Chambers (TOF) Ring Imaging Cherenkov Detector Silicon Tracking Station Dipol magnet

31. μμ Conceptual design and feasibility studies Hyperons Ω (sss) Ξ (dss) track reconstruction efficiency momentum resolution Δp/p J/ψ ψ' ρ,ω,φ D+ Λc • Software tools: • Framework FAIRroot, VMC • Transport codes GEANT3&4, FLUKA • Event generators UrQMD, HSD, PLUTO • Fast track reconstruction algorithms for online event selection • Simulation input: • realistic signal and background multiplicities (e.g. central coll. Au+Au 25 AGeV) • realistic detector layout and response μμ

32. Estimated particle yields: 10 weeks min. bias Au+Au collisions at 25 AGeV

33. CBM Collaboration : 51 institutions, ~ 400 members Croatia: RBI, Zagreb Split Univ. China: CCNU Wuhan USTC Hefei Cyprus: Nikosia Univ. Czech Republic: CAS, Rez Techn.Univ.Prague France: IPHC Strasbourg Hungaria: KFKI Budapest Budapest Univ. Germany: Univ. Heidelberg, P.I. Univ. Heidelberg, KIP Univ. Frankfurt Univ. Mannheim Univ. Münster FZ Dresden GSI Darmstadt Poland: Jag. Univ. Krakow Warsaw Univ. Silesia Univ. Katowice AGH Krakow Portugal: LIP Coimbra 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 MSU, Moscow St. Petersburg P. Univ. Ukraine: Shevshenko Univ. , Kiev India: Aligarh Muslim Univ. Panjab Univ. Rajasthan Univ. Univ. of Jammu Univ. of Kashmir Univ. of Calcutta B.H. Univ. Varanasi VECC Kolkata SAHA Kolkata IOP Bhubaneswar IlT Kharagpur Korea: Korea Univ. Seoul Pusan National Univ. Norway: Univ. Bergen Supported by EU FP6 CBM Collaboration Meeting in Strasbourg Sept. 2006

35. In-medium modification of D-mesons E. Bratkovskaya, W. Cassing How are particles with hidden and open charm produced in nuclear collisions at threshold energies?