Nucleus-nucleus collisions at the future facility in Darmstadt - Compressed Baryonic Matter at GSI Outline:  A future accelerator for intense beams of (rare) ions and antiprotons  The CBM experiment:  Exploring dense baryonic matter  Observables  Technical challenges and solutions Peter Senger

SIS 100 Tm SIS 300 Tm U: 35 AGeV p: 90 GeV Structure of Nuclei far from Stability Cooled antiproton beam: Hadron Spectroscopy Compressed Baryonic Matter The future international accelerator facility Key features: Generation of intense, high-quality secondary beams of rare isotopes and antiprotons. Two rings: simultaneous beams. Ion and Laser Induced Plasmas: High Energy Density in Matter

The phase diagram of strongly interacting matter CERN-SPS, RHIC, LHC: high temperature, low baryon density AGS, GSI (SIS200): moderate temperature, high baryon density

Probing the Chiral phase transition  B  3-8  0, T  130 MeV Restoration of (spontaneously broken) chiral symmetry Origin of hadron masses ?

The production of dense and/or hot hadronic matter Compression + heating = quark-gluon (pion production) matter neutron stars early universe

High energy Au+Au collisions in transport calculations B. Friman, W. Nörenberg, V.D. Toneev Eur. Phys. J. A3 (1998) 165

Pion multiplicities per participating nucleons

Mapping the QCD phase diagram with heavy-ion collisions  B  6  0  B  0.3  0 baryon density:  B  4 ( mT/2  ) 3/2 x [exp((  B -m)/T) - exp((-  B -m)/T)] baryons - antibaryons Analysis of particle ratios with statistical model: chemical freeze-out P. Braun-Munzinger

CBM physics topics and observables 1. In-medium modifications of hadrons  onset of chiral symmetry restoration at high  B measure: , ,   e + e - open charm (D mesons) 2. Strangeness in matter (strange matter?)  enhanced strangeness production ? measure: K, , , ,  3. Indications for deconfinement at high  B  anomalous charmonium suppression ? measure: J/ , D  softening of EOS measure flow excitation function 4. Critical point  event-by-event fluctuations 5. Color superconductivity  precursor effects at T>T c ? Note: In heavy ion collisions ( , ,  )  e + e - not measured from 2 – 40 AGeV J/  not measured below 158 AGeV D mesons not measured at all

p n  ++  K   e+e+ e-e-  p Looking into the fireball … … 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/ ≈185 pairs!

Signatures of the quark-pluon plasma ? Enhanced production of strangeness Anomalous suppression of charmonium (J/  )

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

Comparison of experimental data to results of transport codes E.L. Bratkovskaya, W. Cassing, M. van Leeuwen, S. Soff, H. Stöcker, nucl-th/ “Flow generated by extra pressure generated by partonic interactions in the early phase of a central Au+Au/Pb+Pb collision”

Probing quark-gluon matter with charmonium NA50 Collaboration at CERN: J/  (cc)   +  - (6%) M. C. Abreu and the NA50 Collaboration, Phys. Lett. B 477 (2000) 28 Interpretation: Anomalous J/  suppression in central Pb+Pb collisions caused by color screening of cc mesons in quark-gluon matter

Probing the high density fireball with charm production W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745

25 AGeV Au+Au 158 AGeV Pb+Pb J/  multiplicity in central collisions 1.5· ·10 -3 beam intensity 2·10 8 /s 2·10 7 /s interactions 8·10 6 /s (4%) 2·10 6 /s (10%) central collisions 8·10 5 /s 2·10 5 /s J/  rate 12/s 200/s 6% J/  e + e - (  +  - ) 0.7/s 12/s spill fraction acceptance 0.25  0.1 J/  measured 0.14/s  0.3/s  8·10 4 /week  1.8·10 5 /week J/  experiments: a count rate estimate E lab [GeV]

Hadrons in the nuclear medium

SIS18 SIS300 SIS18: strangeness production at threshold  probing in-medium properties at  = 1 -3  0 SIS300: charm production near threshold  probing in-medium properties at  =  0 Meson production in central Au+Au collisions W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745

Charmed mesons Some hadronic decay modes D  (c  = 317  m): D +  K 0  + (2.9  0.26%) D +  K -  +  + (9  0.6%) D 0 (c  =  m): D 0  K -  + (3.9  0.09%) D 0  K -  +  +  - (7.6  0.4%) experimental challenges: low production cross section large combinatorial background measure displaced vertex with resolution of  30  m D meson production in pN collisions

The critical point gas liquid coexistence Below T c : 1. order phase transition above T c : no phase boundary At the critical point: Large density fluctuations, critical opalescence Event-by-event analysis by NA49: 5% most central Pb+Pb collisions at 158 AGeV Purely statistical fluctuations !

Produce high baryon densities in heavy ion collisions at 4 – 40 AGeV. Build an universal experiment which measures simultaneously both hadrons and electrons: , K, , , , p, , , , , D, J/  (multiplicities, phase-space distributions, centrality, reaction plane). Perform systematic measurements using a dedicated accelerator: High beam intensity and duty cycle, Excellent beam quality, High availability Our approach towards the study of superdense baryonic matter

-- ++ p 25 AGeV central collision URQMD event, GEANT simulation: B = 1 T 160 p 400   + 44 K + 13 K -

Experimental challenges  beam intensities up to 10 9 ions/sec, 1 % interaction target: 10 7 Au+Au reactions/sec (1000 charged particles in central Au+Au collisions at 25 AGeV)  determination of (displaced) vertices with high resolution (  30  m)  identification of electrons and hadrons Silicon: 7 planes, 3 Mio pixel, 1.5 Mio strips Experimental concept  Radiation hard Silicon pixel/strip detectors in a magnetic dipole field  2 electron detectors: pion suppression by  Particle identification: TOF, RICH  Electromagnetic calorimeter  High speed data acquisition and trigger system

Silicon tracker in B field: tracking, momentum RICH1 (   30): electrons RICH2: high-momentum pions (  3-4 GeV/c) TRDs: tracking, electrons (   2000): RPC: particle identification via TOF, kaon-pion separation up to 3-4 GeV/c ECAL: electrons, gammas,  0,  0 The CBM Experiment

Central Au+Au collision at 25 AGeV: URQMD + GEANT4 160 p 400   + 44 K + 13 K -

CBM R&D Collaboration : 35 institutions 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. Münster FZ Rossendorf GSI Darmstadt Russia: CKBM, St. Petersburg IHEP Protvino INR Troitzk ITEP Moscow KRI, St. Petersburg Kurchatov Inst., Moscow LHE, JINR Dubna LPP, JINR Dubna SINP, Moscow State Univ. Spain: Santiago de Compostela Univ. Ukraine: Shevshenko Univ., Kiev USA: LBNL Berkeley Hungaria: KFKI Budapest Eötvös Univ. Budapest Italy: INFN Catania INFN Frascati Korea: Korea Univ. Seoul Pusan Univ. Poland: Krakow Univ. Warsaw Univ. Silesia Univ. Katowice Portugal: LIP Coimbra Romania: NIPNE Bucharest

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

Project cost (M€) Total: 675 Buildings: SIS100: 70.1 SIS200: 39.6 Coll. Ring: 45.0 NESR: 40.0 HESR: 45.0 e-ring: 15.0 Beamlines: 21.0 Cryo, etc: 44.1 SFRS: 40.7 CBM: 27.0 AP: 8.7 Plasma phys.: 8.0 p-linac: 10.0 PANDA: 28.4 pbar targ.: 6.9 Project evolution Oct. 2000: 1. International Workshop on a future accelerator facility Oct : Submission of the Conceptual Design Report Nov. 2002: Positive evaluation report of the German science council Feb. 2003: Project approved by the German federal government (170 M€ foreign contributions requested) Oct. 2003: 2. International Workshop on the future accelerator facility Spring 2004: Letters of intent In 2004: New GSI structure

SIS18 Upgrade 70 MW Connection Proton-Linac TDM # SIS100 Transfer Line SIS18-SIS100 High Energy Beam Lines RIB Prod.-Target, Super-FRS RIB High+Low Energy Branch Antiproton Prod.-Target CR-Complex HESR & 4 MV e - –Cooling NESR SIS200* 8 MV e - –Cooling e-A Collider SIS100/200 Tunnel, SIS Injection+Extraction+Transfer Transfer Buildings/Line Super-FRS, Auxiliary Bldgs., Transfer Tunnel to SIS18, Building APT, Super-FRS, CR-Complex RIB High+Low Energy Branch, HESR ( ground level), NESR, AP-cave, e-A Collider, PP-cave CBM-Cave, Pbar-Cave, Reinjection SIS100 Civil Construction Civil Construction 1 Civil Construction 3 Civil Construction 2 Civil Construction 4 I IV III V II Concept for staged Construction of the International Facility for Beams of Ions and Antiprotons 2,7x10 11 /s 238 U 28+ (200 MeV/u) 5x10 12 protons per puls 1x10 11 /s 238 U 28+ ( GeV/u) ->RIB (50% duty cycle) 2.5x10 13 p (1-30 GeV) 3-30 GeV pbar->fixed target 10.7 GeV/u 238 U -> HADES* 1x10 12 /s 238 U % duty cycle pbar cooled p (1-90 GeV) 35 GeV/u 238 U 92+ NESR physics plasma physics Experiment Potential # Construction Tunnel Drilling Machine General Planning Civil ConstructionProduction and Installation *SIS200 installation during SIS100 shut down

Kopenhagen Titel 1 min 2.Anlage 2 3.phasediagram 1 4.Hot dense matter 2 5.qq condensate 1 6.Filme 2 7.Pionen Excitation 1 8.Transport 1 9.Phasendiagramm 2 10.Observable 2 11.Dilepton Sonde CERES Daten 1 13.QGP NA Transport 1 16.cc production 1 20 min 17.J/psi Vergleich 1 18.Inmedium K, D 1 19.Excitation HSD 1 20.Excit. D-mesons 1 21.Requirements 1 22.CBM CBM URQMD 1 25.Collaboration 1 26.Working packages 1 27.Costs 1 28.Schedule 1 29.Workshop 0 Summe 13

International Accelerator Facility for beams of Ions and Antiprotons

Radiation-hard silicon pixel detectors (LHC development) Idea: identify prompt dimuon pairs and those from decaying D-Dbar pairs by precise vertex-determination Upgrade of NA50 at CERN-SPS: indirect measurement of D-mesons 10 planes 88 pixel readout chips channels pixel size : 50  425  m 2

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

The nuclear reaction experiment at the future facility at GSI CBM ECAL

25 AGeV central collision URQMD event, GEANT simulation: B = 1 T 160 p 400   + 44 K + 13 K - -- p ++

midrapidity 80% 60% incl. decay 67% incl. decay 20% 30% Acceptance Au+Au 25 AGeV URQMD event, GEANT simulation

J/  (x10 5 )  e + e -  0  e + e - counts  (x10 -4 ) cut: p T  1 GeV/c e +, e - opening angle   J/  (x10 5 ) counts  e +, e - transverse momentum cut:   10 o

without cuts (incl. misident. pions) with cuts: p t (e +,e - ) > 1 GeV/c,  lab  25 o,  > 10 o  e + e -  e + e - J/  e + e - N J/  = 1.6 DD  e + e - +X  e + e - counts sum Au+Au 25 AGeV: e + e - invariant mass spectra PLUTO simulations: 10 Mio. events signal/background  10

Simulations on open charm detection: D 0  + K - performed by V. Friese (GSI) Assumptions: Au+Au at 25 AGeV ( : 328  +, 13 K - ) Perfect track finding Perfect particle identification No magnetic field Silicon detector thickness 100  m Tools: URQMD event generator GEANT4 transport code ROOT data analysis

D0D0 ++ ++ K-K- K-K- p  + p K bb bKbK Lab CM pair vzvz ** Suppression of combinatorial background by the following cuts:  invariant mass window m D = 1864  25 MeV  displaced decay vertex v z > 0  back to back emission in c.m. system (  * = 180 o )  impactparameter b pair = b  b K  colinearity of D and decay products (momentum vectors) Identification of D-mesons (open charm) Example: D 0  K -  +

Displaced decay vertex D 0  K -  + signal background S/B Vertex resolution:  vz = 19  m Cut : v z > 0,3 mm Cut-efficiency: Signal: 58.0 % background :2.7 x 10 -4

Impact parameters of K - and  + at z=0 b pair = b K x b  Cut : b pair < -0,004 mm 2 Cut-efficiency: Signal: 90.3 % background: 23.7 % signal background

Colinearity (pointing angle) Cut :  p < 5º Cut-efficiency: Signal: 99.9 % Background : 12.5 % signal background

Total efficiency: Signal: 48.4 % background : 5 x Sensitivity : For = (HSD-Model) und  m = 10 MeV: 3  -limit reached at 1,6 x 10 6 events Signal/Background 1.8 At a reaction rate of 1 MHz (Au+Au central collisions): D 0 detection rate (incl. branching ratio): / h Efficiencies, sensitivity and rates