4 Phasediagram of strongly interacting matter baryochemical potential (~b/0)temperaturehadron liquidQGPcritical point ?super conductivitynucleusK.Rajagopal, Nucl. Phys. A661 (1999) 150hadron gasheatcompression
5 Strongly interacting matter quark gluon plasmabig bang & early universeThadron gasHow to access ???neutron starsr"normal" nuclear matterr=r0=0.17 fm-3
6 Heavy ion collisions simulation of a U+U collision at 23 GeV/A (UrQMD) nucleons mesons excited baryons
7 Heavy ion collisions (II) UrQMD 160 GeV Au+Aubefore collisioncompression and heating (T >> Tchem ~ 160 MeV)thermalization of the "fireball"(high T and r reached for ~10fm/c = s)expansionchemical freezeout (number and type of particles frozen)kinetic freezeout (particle momenta frozen)Tchem ~ 160 MeV ~ 2∙1012 K)(kT unit system, k=8.6∙10-5 eV K-1 → 100 MeV = 1.16∙1012 K !!!)
8 Heavy ion collisions (III) simulation of Au+Au collisions at different beam energies→ maximum baryon densities r increase with beam energy→ energy densities also increase with beam energy[CBM physics group, E. Bratkovskaya, C. Fuchs priv. com.]
9 Heavy ion collisions (IV) in heavy ion collisions nuclear matter can be compressed and heatedstatistical ansatz: describe "final state" hadron gas as grandcanonical ensemble→ temperature T, baryochemical potential mb (relation to baryon density r)→ higher beam energy: higher T, lower mbQCD calculations: difficult ....temperaturecritical point ?QGPbeam energyhadron gasnucleusbaryochemical potential (~b/0)K.Rajagopal, Nucl. Phys. A661 (1999) 150[Andronic et al. Nucl. Phys. A 772, 167 (2006).
11 Lattice - QCD T calculations limited to certain observables and regions of the QCD phase diagramin particular calculations for m ≠ 0 are difficult and conceptual problems could only be solved a few years ago!mbmb = 0→ transition to deconfinement above a certain Tc!Tc ~ 175 MeVdriven by energy densityec ~ 1 GeV/fm3quarks and gluons become relevant degrees of freedom
12 Lattice – QCD (II) phase transition at mb = 0 : crossover = rapid change of properties but no clearly defined phase boundarymb > 0 not yet completely settled ... but:first order phase transition at large mb→ e.g. latent heatphase coexistence regioncritical pointTcrit ~ 160 MeV mcrit ~ 360 MeVchiral symmetry restoration at high T, large mb[F.Karsch, Z. Fodor, S.D.Katz]
13 Experimental statussince 1980s heavy ion collision experiments at AGS, SPS2000 start of RHIC, 2008 LHCRHIC Brookhaven√s = GeV/nucleonfuture: LHCSPS CERNGeV/nucleonAGS Brookhaven2-10 GeV/nucleon[Andronic et al. Nucl. Phys. A 772, 167 (2006).
14 Experimental Status (II) fireball in chemical equilibriumhadron production successfully described by a statistical model ansatz→ all hadron yields (even strangeness!) in chemical equilibriumSPS, RHIC"limiting temperature" T~160 MeV→ phase boundary reached, additional energy goes into heating the QGP[Andronic et al. Nucl. Phys. A 772, 167 (2006).
15 Experimental status (III) energy dedendence of hadron production→ changes in SPS energy regimediscussions ongoing:hadron gas → partonic phasebaryon dominated → meson dominated matterhadron gastransitionQGP?
16 Experimental status – CERN New State of Matter created at CERNAt a special seminar on 10 February, spokespersons from the experiments on CERN* 's Heavy Ion programme presented compelling evidence for the existence of a new state of matter in which quarks, instead of being bound up into more complex particles such as protons and neutrons, are liberated to roam freely.
17 elliptic flow v2particle emission pattern in plane transverse to the reaction planeinitial overlap eccentricity is transformed in momentum anisotropydriven by pressure from overlap regionFourier expansion of the dN/dϕ distribution:v2f
18 Experimental status (IV) all flow observations scale extremely well if taking the underlying number of quarks into account!flow also seen for charm quarks!→ like (all!) quarks flow and combine to hadrons at a later stage (hadronisation)data can only be explained assuming a large, early built up pressure in a nearly ideal liquid (low viscosity!)baryons n=3mesons n=2
19 Experimental status (V) partons should loose energy in a dense and hot medium→ jet suppression!→ results imply huge gluon densities corresponding to an initial temperature of ~2Tcrit and e ~ GeV/fm-3 in the fireball!
20 Experimental status – RHIC RHIC Scientists Serve Up "Perfect" LiquidNew state of matter more remarkable than predicted - raising many new questionsApril 18, 2005TAMPA, FL -- The four detector groups conducting research at the Relativistic Heavy Ion Collider (RHIC) -- a giant atom "smasher" located at the U.S. Department of Energy's Brookhaven National Laboratory -- say they've created a new state of hot, dense matter out of the quarks and gluons that are the basic particles of atomic nuclei, but it is a state quite different and even more remarkable than had been predicted. In peer-reviewed papers summarizing the first three years of RHIC findings, the scientists say that instead of behaving like a gas of free quarks and gluons, as was expected, the matter created in RHIC's heavy ion collisions appears to be more like a liquid.
21 Experimental status - summary partonic phase created in the early phase of A+A collisions for SPS + RHIC energiescharacterization of this phase?→ RHIC: more an ideal liquid than a gas of quarks and gluons, crossover?→ LHC: weakly coupled QGP reachable?→ high baryon density region?where is deconfinement reached first?order of the phase transition? critical point?characteristics of high baryon density matter?2nd generation experiment!CBM at FAIR!10-45 GeV/nucleon[Andronic et al. Nucl. Phys. A 772, 167 (2006).
22 CBM... should be in the right energy range for the "onset of deconfinement", the first order phase transition (and the critical point)... as a 2nd generation experiment can built on the knowledge gained over the last 20 years (observables, experimental techniques)... will be able to use probes never measured before at these energies but expected to be sensitive to the created matter[Bratkovskaya et al., PRC 69 (2004) ]UrQMD calculation of T, mB as function of reaction time(open symbols – nonequilibrium,full symbols – appr. pressure equilibrium)
23 FAIR at GSI SIS 300 p beam 2 – 90 GeV Ca beam 2 – 45 AGeV Au beam 2 – 35 AGeVmax. beam intensity 109 ions/shigh intensity ion beamCompressed Baryonic MatterIon and Laser induced plasmas: High energy density in matterCooled antiproton beam: hadron spectroscopy - PANDASo, just to remind you: CBM will be one of the major experiments at the future FAIR facility next to the existing GSI facility at Darmstadt. FAIR will cover a wide range of physics: From the study of nuclei far from stability with the NUSTAR experiments via hadron spectroscopy with PANDA and plasma physics to the investigation of compressed baryonic matter in nucleus-nucleus collisions with the CBM experiment. With CBM we thus will make use in particular of the high intensity ion beam which will be delivered by the SIS 300 synchrotron. Available beam energies for ions will spread a range from 2 to 35 AGeV for gold ions at beam intensities of up to 10-to-9 ions per second.Structure of nuclei far from stability - NUSTARNovember 7-8, 2007FAIR Kick-Off Event !
24 CBM: Physics topics and Observables The equation-of-state at high Bcollective flow of identified hadronsparticle production at threshold energies (open charm)rare probes!systematic measurements!→ comprehensive picture with CBM as 2nd generation experiment!Deconfinement phase transition at high Bexcitation function and flow of strangeness (K, , , , )excitation function and flow of charm (J/ψ, ψ', D0, D, c)charmonium suppression, sequential for J/ψ and ψ' ?QCD critical endpointexcitation function of event-by-event fluctuations (K/π,...)Onset of chiral symmetry restoration at high Bin-medium modifications of hadrons (,, e+e-(μ+μ-), D)mostly new measurementsCBM Physics Book (theory) in preparation
25 Chiral symmetry restoration chiral broken world:→ chiral partners show different spectral functions!for example: nonstrange I=J=1 multiplet: r- and a1 - mesonchiral symmetry restoration requires that vector and axialvector spectral functions become degenerate→ dramatic reshaping of spectral functions expected!
26 r – meson n p p ++ r e+, μ+ e-, μ- hadronic properties are expected to be affected by the high density matterr-meson couples to the medium, direct radiation from the early phasevector-meson dominance!vacuum lifetime t0 = 1.3 fm/c → dileptons = penetrating probeconnection to chiral symmetry restoration?ne+, μ+e-, μ-rpp++r-mesonspectral function[Rapp, Wambach, Adv. Nucl. Phys. 25 (2000) 1,hep-ph/ ]
27 Charm production at threshold CBM will measure charm production at threshold→ after primordial production, the survival and momentum of the charm quarks depends on the interactions with the dense and hot medium!→ direct probe of the medium!D/p ~ 10-7 → experimental challenge![W. Cassing et al., Nucl. Phys. A 691 (2001) 753]do c and c quarks behave differently in baryon-rich matter?charmonium (cc) in hot and dense matter?relation to deconfinement?HSD simulations
28 interaction ratesFAIR will provide high intensity beams up to 109 ions/shigh availability of beam due to parallel operation of FAIR1% interaction target → 10 MHz interaction rate→ rare probes!(rates for D limited because of readout speed of silicon pixel detectors)BR = branching ratio e = efficiencyT = trigger? Y/10w = yield in 10 weeks
29 STS tracking – heart of CBM Challenge: high track density 600 charged particles in 25o→ trigger on D-mesons for background rejection!Tasktrack reconstruction:0.1 GeV/c < p GeV/cDp/p ~ 1% (p=1 GeV/c)primary and secondary vertex reconstruction (resolution 50 mm)V0 track pattern recognitionsilicon pixeland strip detectorsD+ → p+p+K- (ct = 317 mm)D0 → K-p+ (ct = 124 mm)D0+D0 ~ 1.5∙10-4 central Au+Au, 25 GeV/nucleon
30 CBM – detector concept fixed target experiment, "medium" energies → large solid angle to be coveredhigh rate, multipurpose detector including open charm reconstruction→ fast, excellent tracking based on silicon pixel and strip detectors directly behind the target and inside a magnetic field→ add particle identification afterwards (leptons, hadrons)drives layoutbeamRICHTRDTOFmagnetSTS
31 The CBM experimenttracking, momentum determination, vertex reconstruction: radiation hard silicon pixel/strip detectors (STS) in a magnetic dipole fieldhadron ID: TOF (& RICH)photons, p0, h: ECALPSD for event characterizationhigh speed DAQ and trigger (up to 10 MHz int. rates) → rare probes!electron ID: RICH & TRD p suppression 104muon ID: absorber + detector layer sandwich move out absorbers for hadron runsMVD + STS... measuring both channels would be the best crosscheck of results we can ever do!
32 DAQ & FEE for rare probes highly efficient triggers needed! D-meson → online tracking and 2ndary vertex findingDAQ and FEE concept based on "self triggered readout" electronicsFEE provides self-triggeredhit detection, pre-processingFEECNetBNetHNetto archiveTNetFEE boardsCNet linksDCB: data combiner boardsCDL: CBM detector linksABB: active buffer boardsEB SwitchBackend processorsGeneral NetworkClock/Trigger distributiondata are shipped to PCfarm with a time stamponline event reconstruction:trigger decisionsystem throughput limited!archiving rate 25 kHzstorage: 1Gb/s
33 STS and FEE R&DFast self-triggered readout chip n-XYTER in collaboration with DETNIprospect: CBM-XYTERStrip sensor development with CIS ErfurtFirst test sensor delivered spring 2007
34 Detector R&D – TRD main issue for many detectors: high rates! for example: TRDs → reduce gas gap/ operate with pad plane in the middle of gas gap
35 CbmRoot simulation framework detector simulation (GEANT3)full event reconstruction: track reconstruction, add RICH, TRD and TOF inforesult from feasibility studies in the following: central Au+Au collisions at 25 AGeV beam energy (UrQMD)
36 Hadrons and Hyperons 25 AGeV central AuAu layout of CBM provides also good hyperon (tracking in the STS) and hadron (TOF) identification→ flow, correlations, fluctuations ....ppK
37 Open charm production 25 AGeV central AuAu D0 → K-p+ and D0 → K+p- (ct = 124 mm), full event reconstruction<D0 + D0> = 1.5 ∙ 10-4 (central Au+Au collisions, 25 AGeV)first pixel detector (MAPS) at 10cm~53 mm secondary vertex resolutionproton identification with TOF1012 central Au+Au collisions, 25 AGeV
38 Low mass vector mesons 25 AGeV central AuAu invariant mass spectra electrons: pt > 0.2 GeV/cbackground dominated by physical sources (75%)muons: intrinsic p>1.5 GeV cut (125 cm Fe absorber), use TOF informationbackground dominated by misidentified muonselectrons: 200k eventsbackground 4 ∙108 events – signal 20k ev.All e+e-Comb. bgρ e+e- e+e- φ e+e-π0 γe+e- π0e+e- η γe+e-w,f sm = 14 MeV/c2w,f sm = 11 MeV/c2
39 J/y and y' 25 AGeV central AuAu invariant mass spectra electrons: p < 11 GeV/c, pt > 1 GeV, 1‰ interaction target (25 mm Au)muons: 225 cm Fe absorber, no pt-cutelectrons: 2.4 ∙1010 eventsJ/y sm = 38 MeV/c2y' sm = 45 MeV/c2muons: 4 ∙108 eventsJ/y sm = 22 MeV/c2y' sm = 33 MeV/c2
40 CBM CBM@FAIR – high mB, moderate T: searching for the landmarks of the QCD phase diagramfirst order deconfinement phase transitionchiral phase transitionQCD critical endpointcharacterizing propertiesof baryon dense matterin mediumproperties of hadrons?in A+A collisions from10-45 AGeV(√sNN = 4.5 – 9.3 GeV)starting in 2015
46 Collective flow elliptic flow v2: collapse of elliptic flow of protons at lower energies signal for first order phase transition?! [e.g. Stoecker, NPA 750 (2005) 121, E. Shuryak, hep-ph/ ]full energy dependence needed!elliptic flow v2:initial overlap eccentricity → particle azimuthal distributionsv2centralmidcentralperipheralf[NA49, PRC68, (2003)]
47 K/p fluctuations 2nd order phase transition at the critical point → fluctuations expectedmeasure e.g. particle ratios (K/p) event-by-event and compare to an event averageincrease of K/p fluctuations for lower energies observedinterpretation open
48 Even charm quarks flow!even charm quarks participate in the flow!
49 Relation to EOSmaximum mass in dependence on radius depends strongly on underlying EOS (compressibility of neutron matter!)→ compare with measurements!same for maximum mass and density in the centertry to use constraints on EOS from A+A collisions!Grigorian, Blaschke, Klähn, astro-ph/
50 Detector R&D – RPC R&D HADES main issue for many detectors: high rates!RPC development together with HADES, FOPIupgradesstudy different materials!