Compressed baryonic matter Experiments at GSI and at

Compressed baryonic matter Experiments at GSI and at FAIR Peter Senger (GSI) Outline: Probing dense baryonic matter (1 -3 ρ0) The nuclear equation-of-state In medium properties of strange mesons Towards highest baryon densities (3 -10 ρ0) Exploring the phases of QCD matter Dense Matter In Heavy Ion Collisions and Astrophysics, August 2006, Dubna

Outline: The Facility for Antiproton and Ion Research Compressed Baryonic Matter: the physics case The CBM detector: challenges and possible solutions

The international Facility for Antiproton and Ion Research primary beams • 1012/s; 1. 5 -2 Ge. V/u; 238 U 28+ • factor 100 -1000 increased intensity • 4 x 1013/s 90 Ge. V protons • 1010/s 238 U 35 Ge. V/u ( Ni 45 Ge. V/u) secondary beams • rare isotopes 1. 5 - 2 Ge. V/u; factor 10 000 increased intensity • antiprotons 3(0) - 30 Ge. V storage and cooler rings accelerator technical challenges • Rapidly cycling superconducting magnets • high energy electron cooling • beam losses • beams of rare isotopes • e – A Collider • 1011 stored and cooled antiprotons 0. 8 - 14. 5 Ge. V

Research programs at FAIR Rare isotope beams; nuclear structure and nuclear astrophysics nuclear structure far off stability nucleosynthesis in stars and supernovae Beams of antiprotons: hadron physics quark-confinement potential search for gluonic matter and hybrids hypernuclei high-energy nucleus-nucleus collisions: compressed baryonic matter at highest densities (neutron stars) phase transitions and critical endpoint in-medium properties of hadrons short-pulse heavy ion beams: plasma physics matter at high pressure, densities, and temperature fundamentals of nuclear fusion atomic physics and applied research highly charged atoms low energy antiprotons radiobiology accelerator physics high intensive heavy ion beams dynamical vacuum rapidly cycling superconducting magnets high energy electron cooling

Status Signatures Memorandum of Understanding for the FAIR project (as of November 24, 2005) Country Signatory Date Finland Prof. Dr. D. Riska 22. 09. 2004 France Dr. E. Giacobino 08. 12. 2004 Germany Dr. H. Schunck 13. 09. 2004 Greece Prof. Dr. C. Fotakis 11. 2004 Italy Dr. L. Criscuoli 06. 12. 2004 Poland Prof. Dr. R. Kulessa 18. 01. 2005 Russian Federation Dr. S. Mazurenko 11. 2004 Spain Dr. S. Ordónez Delgado 06. 10. 2004 Sweden Dr. P. Omling 21. 09. 2004 United Kingdom Prof. Dr. J. Wood 13. 09. 2004 China Meng Shuguan / Ma Yanhe 24. 11. 2005 India Dr. Y. P. Kumar 17. 11. 2005 Romania signed in 2006 Observers: EU, USA, Hungary, Austria Cost of the FAIR project: ~ 1 Billion € (25% from foreign partners) German Federal Government has approved construction budget over 10 years Start of civil construction end of 2007

The phase diagram of strongly interacting matter RHIC, LHC: high temperature, low baryon density FAIR: moderate temperature, high baryon density

Mapping the QCD phase diagram with heavy-ion collisions crossover transition LHC lattice QCD RHIC SPS SI S 3 0 0 ? recent data from RHIC: Tfreezeout → 165 Me. V recent L QCD calculations: TC → 190 Me. V Critical endpoint: Z. Fodor, S. Katz, hep-lat/0402006 S. Ejiri et al. , hep-lat/0312006 μB < 400 Me. V: crossover 8 S 1 SI ε=0. 5 Ge. V/fm 3 first order phase transition baryon density: B 4 ( m. T/2 )3/2 x [exp(( B-m)/T) - exp((- B-m)/T)] baryons - antibaryons

Transport calculations: baryon densities Baryon density in central cell (Au+Au, b=0 fm): HSD: mean field, hadrons + resonances + strings QGSM: Cascade, hadrons + resonances + strings C. Fuchs, E. Bratkovskaya, W. Cassing

Transport calculations: energy densities Baryon density in central cell (Au+Au, b=0 fm): HSD: mean field, hadrons + resonances + strings QGSM: Cascade, hadrons + resonances + strings C. Fuchs, E. Bratkovskaya, W. Cassing

“Trajectories” from Ur. QMD L. Bravina, M. Bleicher et al. , PRC 1998

“Trajectories” from 3 fluid hydrodynamics Hadron gas EOS: Y. Ivanov, V. Russkikh, V. Toneev nucl-th/0503088 early phase not in thermodynamic equilibrium !

J. Randrup and J. Cleymans, hep-ph/0607065

Diagnostic probes U+U 23 AGe. V

Compressed Baryonic Matter: physics topics and observables Probing the equation-of-state at high B Observables: collective flow of hadrons, particle production at threshold energies (open charm) Search for a deconfined phase at high B enhanced strangeness production ? Observables: K, , anomalous charmonium suppression ? Observables: charmonium (J/ψ, ψ'), open charm (D 0, D ), c Search for chiral symmetry restoration at high B in-medium modifications of hadrons Observables: , , e+e- , open charm, . . . Search for the 1. order phase transition & the critical endpoint Observable: event-by-event fluctuations (K/π, p. T, . . . )

Towards higher baryonic densities Ch. Fuchs, Tübingen

Meson production in central Au+Au collisions W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745 SIS 18 SIS 100/300

In-medium modification of D-mesons E. Bratkovskaya, W. Cassing

Strangeness/pion ratios versus beam energy C. Blume et al. , nucl-ex/0409008 ? Decrease of baryon-chemical potential: transition from baryon-dominated to meson-dominated matter

Comparison of experimental data to results of transport codes E. L. Bratkovskaya, W. Cassing, M. van Leeuwen, S. Soff, H. Stöcker, nucl-th/0307098 “Flow generated by extra pressure generated by partonic interactions in the early phase of a central Au+Au/Pb+Pb collision”

Intriguing observations by NA 49 @ CERN-SPS critical point Q G P hadrons coexistence phase (non-equilibrium fluctuations) Pb+Pb ? ? next steps: confirmation of NA 49 → Low energy run at RHIC ? comprehensive experimental study → CBM @ FAIR

E-by-E dynamical fluctuations of particle ratios in Ur. QMD Simulations by D. Kresan (GSI), M. Bleicher (Frankfurt): Au+Au 25 AGe. V 4 pi 2 pi Interpretation of e-by-e fluctuations of particle abundances requires detailed information about contribution of resonance decays CBM

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

Dilepton Sources in Heavy-Ion Collisions

Dimuon pairs measured by NA 60 (CERN) In+In 158 AGe. V 5 -week-long run in Oct. –Nov. 2003 ~ 4 × 1012 ions delivered in total Dilepton experiments require: high momentum resolution ( 1 - 2 %) and high statistics

Low mass vector mesons (CERES/CERN) Calculations by R. Rapp: thick dashed line: unmodified rho thick dashed-dotted line: in-medium dropping rho mass thick solid line: in-medium spread rho width D. Adamova et al. , PRL 91 (2003) 042301 CERES 2000: 159 AGe. V Pb+Au ρ, ω, φ → e+e- measurement between no beam intensity: 10 ions / spill 2 and 40 AGe. V +e- (μ+μ-) measurement below 160 AGe. V 1 spill = 4 s beam and 15 s pause no J/ψ → e targets: 13 x 25 μm Au ( ~ 1 % interaction) 6 trigger: 8% most central Event rate = 470 / spill (~ 25 Hz = 15 Mio events/week)

Experimental program of CBM@FAIR Observables: Penetrating probes: , , , J/ → e+e- (μ+μ-) Strangeness: K, , , Open charm: Do, D , Ds, c, global features: collective flow, fluctuations, . . . , exotica Systematic investigations: A+A collisions from 8 to 45 (35) AGe. V, Z/A=0. 5 (0. 4) p+A collisions from 8 to 90 Ge. V p+p collisions from 8 to 90 Ge. V Beam energies up to 8 AGe. V: HADES Detector requirements Large geometrical acceptance (azimuthal symmetry !) good hadron and electron identification excellent vertex resolution high rate capability of detectors, FEE and DAQ Large integrated luminosity: High beam intensity and duty cycle, Available for several month per year

Experimental challenges Central Au+Au collision at 25 AGe. V: URQMD + GEANT 4 160 p 400 + 44 K+ 13 K- up to 107 Au+Au reactions/sec (beam intensities up to 109 ions/sec, 1 % interaction target) determination of (displaced) vertices with high resolution ( 50 m) identification of electrons and hadrons

The Compressed Baryonic Matter Experiment Silicon Tracking System (STS) Radiation hard Silicon (pixel/strip) Tracking System in a magnetic dipole field Electron detectors: RICH & TRD & ECAL: pion suppression better 104 Hadron identification: TOF-RPC Measurement of photons, π, η, and muons: electromagn. calorimeter (ECAL) High speed data acquisition and trigger system

Acceptance for particles identified by TOF Very important for the measurement of event-by-event fluctuations: a large and azimuthally symmetric acceptance 100 % purity:

Hyperon detection with STS without p, K, π identification central Au+Au collisions at 25 AGe. V: (uds) - (dss) - (sss) efficiency 15. 8% 6. 7% 7. 7%

D+ mesons from Au+Au collisions at 25 AGe. V Track reconstruction: realistic magnetic field, 7 pixel detectors (no strips yet), no particle ID required D+ production cross section from HSD 25 AGe. V Au+Au from Ur. QMD 81000 D+ mesons registered in 1012 min. bias Au+Au collisions at 25 AGe. V → 1 day run with fast and rad hard vertex detector and tracking trigger → 100 days run with todays MAPS vertex detector without trigger

Electron-positron pairs from Au+Au collisions at 25 AGe. V Simulations without track reconstruction & electron identification Experimental challenge: branching ratios ~ 10 -5 -10 -4 for ρ, ω, φ → e+ecombinatorial background ρ ω φ major sources of physical background: Dalitz decays π0→ e+e-γ gamma conversion γ → e+e- Signal/Background ( 1. 4 σ): s/b = 0. 5 at mass of ω meson s/b = 0. 3 at mass of φ meson

Feasibility studies: charmonium measurements Assumptions: no track reconstruction (momentum resolution 1%) ideal electron identification, pion suppression 104 Background: central Au + Au Ur. QMD + GEANT 4 Cut p. T > 1 Ge. V/c 15 AGe. V Au+Au J/ψ Single electron (positron) spectra J/ψ 25 AGe. V Au+Au J/ψ ongoing work: track reconstruction (STS-TRD) electron identification (RICH+TRD) 35 AGe. V Au+Au

Study of μ ID system with absorber for CBM C/Fe absorbers + detector layers J/ψ→μ+μs/b ~ 100 Simulations Au+Au 25 AGe. V: track reconstruction from hits in Problems: and muonfor chambers low. STS efficiency small invariant masses (100 μmatposition resolution) 2 ) (cut-off 200 Me. V/c low efficiency for soft muons from ρ, ω, φ→μ+μ muon ID: tracks from STS to Challenging muon detector (high particle densities) muon chamber behind absorber vector meson multiplicities from HSD transport code ρω φ

Experimental requirements and ongoing R&D Silicon Pixel (Vertex) Detector: • low materal budget: d < 200 μm • single hit resolution < 20 μm • radiation hardness (dose 1015 neq/cm 2) • fast read out Transition Radiation Detector: • e/π discrimination of > 100 (p > 1 Ge. V/c) • High rate capability up to 100 k. Hz/cm 2 • Position resolution of about 200 μm • Large area ( 450 - 650 m 2, 9 – 12 layers) Si-Strip detectors: • pitch 50 μm • thickness 150 μm • double sided, stereo angle 15 o • Area 2 m 2 Resistive Plate Chamber (To. F-RPC): • Time resolution ≤ 80 ps • High rate capability up to 25 k. Hz/cm 2 • Efficiency > 95 % • Area 100 m 2 Ring Imaging Cherenkov Detector: • e/π discrimination > 100 • hadron blind up to about 6 Ge. V/c • low mass mirrors • fast UV detector Electromagnetic Calorimeter: • energy resolution of 5 / E(Ge. V) • high rate capability up to 15 k. Hz • e/π discrimination of 50 -200 • Area 100 m 2 Muon detection system: • fast gas chambers (GEM) • high granularity FEE and DAQ: self triggered digitization, dead time free

CBM 8 – 45 AGe. V HADES 2 – 8 AGe. V

CBM Collaboration : > 40 institutions, > 350 Members Croatia: RBI, Zagreb China: Wuhan Univ. Hefei Univ. Korea: Korea Univ. Seoul Pusan National Univ. Romania: NIPNE Bucharest Russia: Norway: IHEP Protvino Univ. Bergen INR Troitzk ITEP Moscow Germany: Cyprus: Univ. Heidelberg, Phys. Inst. KRI, St. Petersburg Nikosia Univ. Kurchatov Inst. , Moscow Univ. HD, Kirchhoff Inst. Czech Republic: LHE, JINR Dubna Univ. Frankfurt CAS, Rez LPP, JINR Dubna Univ. Kaiserslautern Techn. Univ. Prague LIT, JINR Dubna Univ. Mannheim MEPHI Moscow France: Univ. Münster Obninsk State Univ. IRe. S Strasbourg FZ Rossendorf PNPI Gatchina GSI Darmstadt Hungaria: SINP, Moscow State Univ. Poland: KFKI Budapest St. Petersburg Polytec. U. Krakow Univ. Eötvös Univ. Budapest Ukraine: Warsaw Univ. India: Shevshenko Univ. , Kiev Silesia Univ. Katowice VECC Kolkata Nucl. Phys. Inst. Krakow* SAHA Kolkata* Portugal: IOP Bhubaneswar* * to be approved by CB LIP Coimbra Univ. Chandighar*

Technical Status Report: http: //www. gsi. de/fair/experiments/CBM Workshop on the Physics of Compressed Baryonic Matter Dec. 15 – 16, 2005 at GSI Transparencies can be found on http: //www-aix. gsi. de/conferences/cbm 2005 -Dec/ Workshop on the Physics of high baryon density May 29 - June 2, 2006 at ECT* in Trento, Italy Next steps: CBM Physics Book CBM Technical Proposal

Transport calculations: equilibrated system ? Baryon density in central cell (Au+Au, b=0 fm): HSD: mean field, hadrons + resonances + strings QGSM: Cascade, hadrons + resonances + strings C. Fuchs, E. Bratkovskaya, W. Cassing