1. The CBM Experiment @ FAIR Volker Friese Gesellschaft für Schwerionenforschung Darmstadt  HI physics at intermediate beam energies  CBM detector concept  feasibility studies  status

2. Volker FrieseQM 2005, Budapest, August 20052 HI collisions at intermediate energies beam energies 10 – 45 AGeV give access to:  highest baryon densities  onset of phase transition (?)  critical point (?)

3. Volker FrieseQM 2005, Budapest, August 20053 Trajectories in the QCD phase diagram V.Toneev et al., nucl-th/0309008 3 fluid hydro calculation with hadron gas EOS predicts 30 AGeV to hit critical point phase boundary reached already at 10 AGeV

4. Volker FrieseQM 2005, Budapest, August 20054 Indications for onset of deconfinement at low SPS energies NA49 (QM 2004) peak in strange/nonstrange yield ratio plateau of kaon slopes at SPS not satisfactorily explained in hadronic scenarios Hama et al., Braz. J. Phys. 34 (2004) 322 Gazdzicki, Gorenstein, Act. Phys. Polon. B 30 (1999) 2705 can be modeled assuming 1st order phase transition

5. Volker FrieseQM 2005, Budapest, August 20055 Hadrons in dense environment CERES, Phys. Rev. Lett. 91, 042301 (2003) enhancement of low-mass dileptons stronger in 40 AGeV than in 158 AGeV even larger effect at lower energies? statistics and resolution must be improved to discriminate different in-medium scenarios

6. Volker FrieseQM 2005, Budapest, August 20056 J/ψ suppression NA50, QM 2005Gazdzicki & Gorenstein, Phys. Rev. Lett. 83 (1999) 4009 anomalous suppression observed at top SPS in J/ψ / DY but J/ψ / h- flat vs centrality (?) onset of suppression at lower energies ?

7. Volker FrieseQM 2005, Budapest, August 20057 Charm near threshold Gorenstein et al J. Phys. G 28 (2002) 2151 predictions of ccbar production differ strongly between production scenarios (pQCD / QGP / hadron gas) strongest differences near threshold experiment should be able to discriminate

8. Volker FrieseQM 2005, Budapest, August 20058 Charm in dense matter Cassing et al, Nucl. Phys. A 691 (2001) 753 Mishra et al, nucl-th/0308082 D meson masses are expected to drop in dense environment should have strong effect on production yield

9. Volker FrieseQM 2005, Budapest, August 20059 Charm in dense matter (ctd.) Mishra et al, nucl-th/0308082 effect of reduced affectiv D mass: strong decay channels open for charmonium states observable in J/ψ yield in dileptons ?

10. Volker FrieseQM 2005, Budapest, August 200510 The physics of CBM in-medium properties of hadrons deconfinement at high ρ B critical point strangeness (K, Λ, Σ, Ξ, Ω) charm (J/ψ, D) flow ρ, ω, φ → e + e - open charm fluctuations ?!

11. Volker FrieseQM 2005, Budapest, August 200511 FAIR @ GSI SIS 100 Tm SIS 300 Tm U: 35 AGeV p: 90 GeV

12. Volker FrieseQM 2005, Budapest, August 200512 Detector considerations fast detector response and readout radiation hard detectors and electronics efficient online event selection high interaction rates (beam intensity 10 9 /s, high availability) rare observables (Ω, J/ψ, D) STS tracking, displaced vertices ECAL lepton ID photons TOF hadron ID RICH electron ID TRD electron ID

13. Volker FrieseQM 2005, Budapest, August 200513 Baseline detector concept beam magnet STS ( 5 – 100 cm) RICH (1,5 m) TRDs (4,6,8 m) TOF (10 m) ECAL (12 m)

14. Volker FrieseQM 2005, Budapest, August 200514 The Silicon Tracking System vacuum 1 7 3 4 vertexing tra c king 2 5 6 pixel detectors strip detectors z = 5,10,(20) cm z = (20),40,60,80,100 cm "minimal setup": 3 pixel stations 4 strip stations momentum resolution < 1 %

15. Volker FrieseQM 2005, Budapest, August 200515 RICH Design requests: electron ID p < 10 GeV/c pion suppression > 100 pion ID p > 4-5 GeV/c mirror: Be glass, r=450 cm two focal planes radiator: γ > 38 (e. g. N 2 ) z (beam) y optical layout rings in focal plane ring radius vs momentum

16. Volker FrieseQM 2005, Budapest, August 200516 TRD serves for e/π separation and tracking position resolution 300 μm count rates up to 150 kHz/cm 2 R&D ongoing for fast gas detectors Readout: MWPC/GEM/Straw tube beam test July 2004, GSI TR-Simulation

17. Volker FrieseQM 2005, Budapest, August 200517 Detector performance: acceptance incl. TOF 1035 AGeV Λ ΞΩ bulk of produced hadrons covered by acceptance

18. Volker FrieseQM 2005, Budapest, August 200518 Detector performance: J/ψ 15 AGeV25 AGeV35 AGeV single electron p t Simulation: J/ψ, D – HSD background – UrQMD momentum resolution 1 % pion suppression 10 4 p t cut 1 GeV/c, S/B ≈ 1 count rate 10 5 /week

19. Volker FrieseQM 2005, Budapest, August 200519 Detector performance: D mesons Simulation: STS only (no PID) with MAPS 10 11 events Challenge: Implementation of secondary vertex cut in online event selection (reduction ≈ 1000 needed)

20. Volker FrieseQM 2005, Budapest, August 200520 CBM: Status Nov. 2001: FAIR Conceptual Design Report Jul. 2002: FAIR Recommendation by german Wissenschaftsrat Feb. 2003: approved by BMBF Jan. 2004: CBM Letter of Intent Jan. 2005: CBM Technical Status Report Next step: Technical Proposal (ca. 2 years) First beam on target in 2014

21. Volker FrieseQM 2005, Budapest, August 200521 The CBM collaboration Croatia: RBI, Zagreb Cyprus: Nikosia Univ. Czech Republic: Czech Acad. Science, Rez Techn. Univ. Prague France: IReS Strasbourg Germany: Univ. Heidelberg, Phys. Inst. Univ. HD, Kirchhoff Inst. Univ. Frankfurt Univ. Mannheim Univ. Marburg Univ. Münster FZ Rossendorf GSI Darmstadt Romania: NIPNE Bucharest Russia: CKBM, St. Petersburg IHEP Protvino INR Troitzk ITEP Moscow KRI, St. Petersburg Kurchatov Inst., Moscow LHE, JINR Dubna LPP, JINR Dubna LIT, JINR Dubna PNPI Gatchina SINP, Moscow State Univ. Spain: Santiago de Compostela Univ. Ukraine: Univ. Kiev Hungaria: KFKI Budapest Eötvös Univ. Budapest Italy: INFN Frascati Korea: Korea Univ. Seoul Pusan National Univ. Norway: Univ. Bergen Poland: Jagiel. Univ. Krakow Silesia Univ. Katowice Warsaw Univ. Warsaw Tech. Univ. Portugal: LIP Coimbra