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

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

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

Volker FrieseQM 2005, Budapest, August 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

Volker FrieseQM 2005, Budapest, August Hadrons in dense environment CERES, Phys. Rev. Lett. 91, (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

Volker FrieseQM 2005, Budapest, August 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 ?

Volker FrieseQM 2005, Budapest, August 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

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

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

Volker FrieseQM 2005, Budapest, August 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 ?!

Volker FrieseQM 2005, Budapest, August GSI SIS 100 Tm SIS 300 Tm U: 35 AGeV p: 90 GeV

Volker FrieseQM 2005, Budapest, August 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

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

Volker FrieseQM 2005, Budapest, August The Silicon Tracking System vacuum vertexing tra c king 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 %

Volker FrieseQM 2005, Budapest, August 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

Volker FrieseQM 2005, Budapest, August 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

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

Volker FrieseQM 2005, Budapest, August 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

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

Volker FrieseQM 2005, Budapest, August 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

Volker FrieseQM 2005, Budapest, August 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