Nucleus-nucleus collisions at the future facility in Darmstadt - - PowerPoint PPT Presentation

Nucleus-nucleus collisions at the future facility in Darmstadt - Compressed Baryonic Matter at GSI Peter Senger Outline: � Dense baryonic matter: fundamental physics � Experimental observables � Technical challenges and (possible) solutions

States of strongly interacting matter baryons hadrons partons Compression + heating = quark-gluon plasma (pion production) Neutron stars Early universe

Mapping the QCD phase diagram with heavy-ion collisions P. Braun-Munzinger temperature T [ MeV ] 250 Analysis of particle ratios quark-gluon plasma with statistical model: 200 chemical freeze-out RHIC SPS Lattice QCD Critical Point 150 SIS300 Dense Baryonic Medium ρ B ≈ 6 ρ 0 AGS 100 SIS n b =0.12 fm -3 baryon density: Dilute Hadronic Medium 50 ρ B ≈ 0.3 ρ 0 atomic ρ B ≈ 4 ( mT/2 π ) 3/2 x nuclei neutron stars [exp(( µ B -m)/T) - exp((- µ B -m)/T)] 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 baryons - antibaryons baryonic chemical potential µ B [ GeV ]

Fundamental questions: � Equation-of-state at high densities: stability of neutron stars, supernova dynamics � In-medium hadron properties: chiral symmetry restoration, origin of hadron masses? � deconfinement

Experimental situation : Strangeness production Experimental situation : Strangeness enhancement ? in central Au+Au and Pb+Pb collisions New results from NA49 (CERN Courier Oct. 2003) SIS SIS 100 100 300 300 Statistical hadron gas model P. Braun-Munzinger et al. Nucl. Phys. A 697 (2002) 902

CBM physics topics and observables 1. In-medium modifications of hadrons � onset of chiral symmetry restoration at high ρ B measure: ρ , ω , φ → e + e - open charm (D mesons) 2. Strangeness in matter (strange matter?) � enhanced strangeness production ? measure: K, Λ , Σ , Ξ , Ω 3. Indications for deconfinement at high ρ B � anomalous charmonium suppression ? measure: J/ ψ , D � softening of EOS measure flow excitation function 4. Critical point � event-by-event fluctuations

Looking into the fireball … n π p p Λ π ρ e + ++ ∆ K e - … using penetrating probes: short-lived vector mesons decaying into electron-positron pairs

Invariant mass of electron-positron pairs from Pb+Au at 40 AGeV CERES Collaboration S. Damjanovic and K. Filimonov, nucl-ex/0109017 -4 -4 10 10 -1 CERES/NA45 Pb-Au 40 AGeV -1 CERES/NA45 Pb-Au 40 AGeV ) ) 2 2 > (100 MeV/c > (100 MeV/c Preliminary σ σ Preliminary ≈ / 30 % σ σ ≈ / 30 % geo geo η -5 <dN /d >=210 η -5 <dN /d >=210 10 ch 10 ch η η 2.1< <2.65 2.1< <2.65 p >200 MeV/c p >200 MeV/c t t Θ >35 mrad Θ >35 mrad ch ch ee -6 ee -6 >/<N 10 >/<N 10 η → ee ee ee γ /dm /dm ω -7 → -7 10 ee 10 ee ee π 0 <dN <dN ee γ ee → → ω 0 π ee η ee -8 ⁄ ≈ 185 pairs! -8 → → 10 10 → ee ρ γ φ -9 -9 10 10 0 0.2 0.4 0.6 0.8 1 1.2 0 0.2 0.4 0.6 0.8 1 1.2 2 2 m (GeV/c ) m (GeV/c ) ee ee Number of pairs for m>0.2 GeV/c2: 180+-48 Hadronic decay cocktail Ratio Signal/Background: 1/6 Hadronic decay cocktail: + Vacuum rho spectral function - particle ratios taken from thermal model for Pb-Pb + Rho spectral function with dropping mass -rapidity and pt distributions from systematics in Pb-Pb + In-medium rho spectral function Enhancement: measured pairs/decay cocktail: 5.0 +- 1.3 + Lowest order pQCD rate

Signatures of the quark-pluon plasma ? Anomalous suppression of charmonium (J/ ψ ) ???

Charmed mesons D meson production in pN collisions Some hadronic decay modes D ± (c τ = 317 µ m): D + → K 0 π + (2.9 ± 0.26%) D + → K - π + π + (9 ± 0.6%) D 0 (c τ = 124.4 µ m): D 0 → K - π + (3.9 ± 0.09%) D 0 → K - π + π + π - (7.6 ± 0.4%) D mesons not yet measured in heavy-ion collisions !

Experimental challenges Central Au+Au collision at 25 AGeV: URQMD + GEANT4 160 p 400 π - 400 π + 44 K + 13 K - � 10 7 Au+Au reactions/sec (beam intensities up to 10 9 ions/sec, 1 % interaction target) � determination of (displaced) vertices with high resolution ( ≈ 30 µ m) � identification of electrons and hadrons

The CBM Experiment � Radiation hard Silicon pixel/strip detectors in a magnetic dipole field � Electron detectors: RICH & TRD & ECAL: pion suppression up to 10 5 � Hadron identification: RPC, RICH � Measurement of photons, π , η , and muons: electromagn. calorimeter (ECAL) � High speed data acquisition and trigger system

CBM R&D working packages Feasibility, Design & construction Data Acquis., Simulations of detectors Analysis GEANT4: GSI Silicon Pixel Fast TRD Trigger, ρ , ω , ϕ → e + e - DAQ IReS Strasbourg JINR-LHE, Dubna Frankfurt Univ., GSI Darmstadt, Univ. Krakow KIP Univ. Heidelberg GSI Darmstadt, Univ. Münster JINR-LHE Dubna Univ. Mannheim RBI Zagreb, INFN Frascati GSI Darmstadt Univ. Krakow D → K π ( π ) JINR-LIT, Dubna LBNL Berkeley Straw tubes KFKI Budapest GSI Darmstadt, Silesia Univ. Katowice JINR-LPP, Dubna Czech Acad. Sci., Rez Silicon Strip Univ. Warsaw FZ Rossendorf Techn. Univ. Prague SINP Moscow State U. FZ Jülich CKBM St. Petersburg Tech. Univ. Warsaw Analysis J/ ψ → e + e - KRI St. Petersburg GSI Darmstadt, INR Moscow ECAL Heidelberg Univ, RPC-TOF ITEP Moscow Hadron ID GSI Darmstadt LIP Coimbra, Heidelberg Univ, Univ. Krakow Univ. Santiago de Com., Warsaw Univ. Univ. Heidelberg, RICH Kiev Univ. GSI Darmstadt, NIPNE Bucharest Warsaw Univ. IHEP Protvino INR Moscow NIPNE Bucharest GSI Darmstadt INR Moscow Tracking FZ Rossendorf Magnet IHEP Protvino KIP Univ. Heidelberg ITEP Moscow JINR-LHE, Dubna Univ. Mannheim GSI Darmstadt JINR-LHE Dubna

CBM R&D Collaboration : 39 institutions , 15 countries Croatia: Hungaria: Russia: RBI, Zagreb KFKI Budapest CKBM, St. Petersburg Eötvös Univ. Budapest IHEP Protvino Cyprus: INR Troitzk Nikosia Univ. Italy: ITEP Moscow INFN Catania KRI, St. Petersburg Czech Republic: INFN Frascati Kurchatov Inst., Moscow Czech Acad. Science, Rez LHE, JINR Dubna Techn. Univ. Prague Korea: LPP, JINR Dubna Korea Univ. Seoul LIT, JINR Dubna France: Pusan Univ. PNPI Gatchina IReS Strasbourg SINP, Moscow State Univ. Poland: Germany: Jagiel. Univ. Krakow Spain: Univ. Heidelberg, Phys. Inst. Silesia Univ. Katowice Santiago de Compostela Univ. Univ. HD, Kirchhoff Inst. Warsaw Univ. Univ. Frankfurt Warsaw Tech. Univ. Ukraine: Univ. Mannheim Univ. Kiev Univ. Marburg Portugal: Univ. Münster LIP Coimbra USA: FZ Rossendorf LBNL Berkeley Romania: GSI Darmstadt NIPNE Bucharest

CBM Participation in EU Programmes: EU FP6 Hadron Physics INTAS-GSI (2004-2005) (2004 – 2006) approved projects: Joint Research Projects (approved): • Transition Radiation Detectors • Straw tube tracker • Fast gaseous detectors (Univ. Tech. Warszawa) Partner: INVENTOR, Krakow • Resistive Plate Chambers • Advanced TOF Systems • Electromagnetic calorimeter • Future DAQ and trigger systems (Univ. Krakow) (Silesia Univ. Katowice, Univ. Warszawa) Network activities (approved): New call EU FP6 • CBMnet (opened Nov.03, closed Mar04): (Silesia Univ. Katowice, Univ. Krakow, Univ. Warszawa) • Design of new facilities • Construction of new facilities

The nuclear reaction experiment at the future facility at GSI CBM HADES A+A at 8-40 AGeV A+A at 2-8 AGeV