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Das CBM Experiment bei FAIR - Untersuchungen des QCD Phasendiagrams bei hohen Baryonendichten - Claudia Höhne, GSI Darmstadt CBM collaboration.

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Presentation on theme: "Das CBM Experiment bei FAIR - Untersuchungen des QCD Phasendiagrams bei hohen Baryonendichten - Claudia Höhne, GSI Darmstadt CBM collaboration."— Presentation transcript:

1 Das CBM Experiment bei FAIR - Untersuchungen des QCD Phasendiagrams bei hohen Baryonendichten - Claudia Höhne, GSI Darmstadt CBM collaboration

2 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Outline Introduction & motivation phase diagram of strongly interacting matter A+A collisions theoretical status experimental status CBM experiment observables detector layout detector R&D feasibility studies Summary & Outlook

3 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Phasediagram of water H2OH2O

4 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Phasediagram of strongly interacting matter baryochemical potential (~ b / 0 ) temperature hadron liquid QGP critical point ? super conductivity nucleus K.Rajagopal, Nucl. Phys. A661 (1999) 150 hadron gas compression heat

5 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Strongly interacting matter T big bang & early universe "normal" nuclear matter = 0 =0.17 fm -3 neutron stars hadron gas quark gluon plasma How to access ???

6 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Heavy ion collisions simulation of a U+U collision at 23 GeV/A (UrQMD) nucleonsmesonsexcited baryons

7 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Heavy ion collisions (II) UrQMD 160 GeV Au+Au before collision compression and heating (T >> T chem ~ 160 MeV) thermalization of the "fireball" (high T and reached for ~10fm/c = s) expansion chemical freezeout (number and type of particles frozen) kinetic freezeout (particle momenta frozen) T chem ~ 160 MeV ~ K) (kT unit system, k= eV K MeV = K !!!)

8 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Heavy ion collisions (III) [CBM physics group, E. Bratkovskaya, C. Fuchs priv. com.] simulation of Au+Au collisions at different beam energies maximum baryon densities increase with beam energy energy densities also increase with beam energy

9 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Heavy ion collisions (IV) in heavy ion collisions nuclear matter can be compressed and heated statistical ansatz: describe "final state" hadron gas as grandcanonical ensemble temperature T, baryochemical potential b (relation to baryon density ) higher beam energy: higher T, lower b QCD calculations: difficult.... [Andronic et al. Nucl. Phys. A 772, 167 (2006). baryochemical potential (~ b / 0 ) temperature QGP critical point ? nucleus K.Rajagopal, Nucl. Phys. A661 (1999) 150 hadron gas beam energy

10 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, SB CSC QGP Lattice QCD Ginzburg-Landau + RG Nuclear theory Perturbative QCD effective models Theoretical status

11 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Lattice - QCD calculations limited to certain observables and regions of the QCD phase diagram in particular calculations for 0 are difficult and conceptual problems could only be solved a few years ago! T b b = 0 transition to deconfinement above a certain T c ! T c ~ 175 MeV driven by energy density c ~ 1 GeV/fm 3 quarks and gluons become relevant degrees of freedom

12 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Lattice – QCD (II) [F.Karsch, Z. Fodor, S.D.Katz] phase transition at b = 0 : crossover = rapid change of properties but no clearly defined phase boundary b > 0 not yet completely settled... but: first order phase transition at large b e.g. latent heat phase coexistence region critical point T crit ~ 160 MeV crit ~ 360 MeV chiral symmetry restoration at high T, large b

13 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Experimental status [Andronic et al. Nucl. Phys. A 772, 167 (2006). AGS Brookhaven 2-10 GeV/nucleon SPS CERN GeV/nucleon RHIC Brookhaven s = GeV/nucleon future: LHC since 1980s heavy ion collision experiments at AGS, SPS 2000 start of RHIC, 2008 LHC

14 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Experimental Status (II) "limiting temperature" T~160 MeV phase boundary reached, additional energy goes into heating the QGP [Andronic et al. Nucl. Phys. A 772, 167 (2006). SPS, RHIC fireball in chemical equilibrium hadron production successfully described by a statistical model ansatz all hadron yields (even strangeness!) in chemical equilibrium

15 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Experimental status (III) energy dedendence of hadron production changes in SPS energy regime discussions ongoing: hadron gas partonic phase baryon dominated meson dominated matter hadron gas QGP transition ?

16 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Experimental status – CERN New State of Matter created at CERNState of Matter At 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.CERN

17 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, elliptic flow v2 particle emission pattern in plane transverse to the reaction plane initial overlap eccentricity is transformed in momentum anisotropy driven by pressure from overlap region Fourier expansion of the dN/d ϕ distribution: v2v2

18 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, 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=3 mesons n=2

19 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, 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 ~2T crit and ~ GeV/fm -3 in the fireball!

20 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Experimental status – RHIC RHIC Scientists Serve Up "Perfect" Liquid New state of matter more remarkable than predicted - raising many new questions April 18, 2005 TAMPA, 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.Relativistic Heavy Ion Colliderpeer-reviewed papers

21 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Experimental status - summary [Andronic et al. Nucl. Phys. A 772, 167 (2006). partonic phase created in the early phase of A+A collisions for SPS + RHIC energies characterization 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! GeV/nucleon

22 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, CBM [Bratkovskaya et al., PRC 69 (2004) ] UrQMD calculation of T, B as function of reaction time (open symbols – nonequilibrium, full symbols – appr. pressure equilibrium)... 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

23 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, FAIR at GSI Ion and Laser induced plasmas: High energy density in matter high intensity ion beam Compressed Baryonic Matter Cooled antiproton beam: hadron spectroscopy - PANDA Structure of nuclei far from stability - NUSTAR SIS 300 p beam 2 – 90 GeV Ca beam 2 – 45 AGeV Au beam 2 – 35 AGeV max. beam intensity 10 9 ions/s November 7-8, 2007 FAIR Kick-Off Event !

24 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, CBM: Physics topics and Observables Onset of chiral symmetry restoration at high B in-medium modifications of hadrons (,, e + e - (μ + μ - ), D) Deconfinement phase transition at high B excitation function and flow of strangeness (K,,,, ) excitation function and flow of charm (J/ψ, ψ', D 0, D, c ) charmonium suppression, sequential for J/ψ and ψ' ? The equation-of-state at high B collective flow of identified hadrons particle production at threshold energies (open charm) QCD critical endpoint excitation function of event-by-event fluctuations (K/π,...) mostly new measurements CBM Physics Book (theory) in preparation rare probes! systematic measurements! comprehensive picture with CBM as 2nd generation experiment!

25 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Chiral symmetry restoration chiral broken world: chiral partners show different spectral functions! for example: nonstrange I=J=1 multiplet: and a 1 - meson chiral symmetry restoration requires that vector and axialvector spectral functions become degenerate dramatic reshaping of spectral functions expected!

26 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, – meson [Rapp, Wambach, Adv. Nucl. Phys. 25 (2000) 1, hep-ph/ ] hadronic properties are expected to be affected by the high density matter -meson couples to the medium, direct radiation from the early phase vector-meson dominance! vacuum lifetime 0 = 1.3 fm/c dileptons = penetrating probe connection to chiral symmetry restoration? p n ++ p e +, μ + e -, μ - -meson spectral function

27 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Charm production at threshold [W. Cassing et al., Nucl. Phys. A 691 (2001) 753] HSD simulations 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! do c and c quarks behave differently in baryon-rich matter? charmonium (cc) in hot and dense matter? relation to deconfinement? D / ~ experimental challenge!

28 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, interaction rates FAIR will provide high intensity beams up to 10 9 ions/s high availability of beam due to parallel operation of FAIR 1% interaction target 10 MHz interaction rate rare probes! (rates for D limited because of readout speed of silicon pixel detectors) BR = branching ratio = efficiency T = trigger?Y/10w = yield in 10 weeks

29 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, STS tracking – heart of CBM Challenge: high track density 600 charged particles in 25 o trigger on D-mesons for background rejection! Task track reconstruction: 0.1 GeV/c < p GeV/c p/p ~ 1% (p=1 GeV/c) primary and secondary vertex reconstruction (resolution 50 m) V 0 track pattern recognition D K - (c = 317 m) D 0 K - + (c = 124 m) silicon pixel and strip detectors D 0 +D 0 ~ central Au+Au, 25 GeV/nucleon

30 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, CBM – detector concept fixed target experiment, "medium" energies large solid angle to be covered high 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) beam magnet STS RICH TRD TOF drives layout

31 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, The CBM experiment tracking, momentum determination, vertex reconstruction: radiation hard silicon pixel/strip detectors (STS) in a magnetic dipole field hadron ID: TOF (& RICH) photons, 0, : ECAL electron ID: RICH & TRD suppression 10 4 PSD for event characterization high speed DAQ and trigger (up to 10 MHz int. rates) rare probes! muon ID: absorber + detector layer sandwich move out absorbers for hadron runs MVD + STS... measuring both channels would be the best crosscheck of results we can ever do!

32 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, DAQ & FEE for rare probes highly efficient triggers needed! D-meson online tracking and 2ndary vertex finding DAQ and FEE concept based on "self triggered readout" electronics FEE CNet BNet HNet to archive TNet FEE boards CNet links DCB: data combiner boards CDL: CBM detector links ABB: active buffer boards EB Switch Backend processors General Network Clock/Trigger distribution data are shipped to PC farm with a time stamp online event reconstruction: trigger decision system throughput limited! archiving rate 25 kHz storage: 1Gb/s FEE provides self-triggered hit detection, pre-processing

33 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, STS and FEE R&D Strip sensor development with CIS Erfurt First test sensor delivered spring 2007 Fast self-triggered readout chip n-XYTER in collaboration with DETNI prospect: CBM-XYTER

34 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, 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 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, CbmRoot simulation framework detector simulation (GEANT3) full event reconstruction: track reconstruction, add RICH, TRD and TOF info result from feasibility studies in the following: central Au+Au collisions at 25 AGeV beam energy (UrQMD)

36 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Hadrons and Hyperons K p layout of CBM provides also good hyperon (tracking in the STS) and hadron (TOF) identification flow, correlations, fluctuations AGeV central AuAu

37 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Open charm production D 0 K - + and D 0 K + - (c = 124 m), full event reconstruction = (central Au+Au collisions, 25 AGeV) first pixel detector (MAPS) at 10cm ~53 m secondary vertex resolution proton identification with TOF central Au+Au collisions, 25 AGeV 25 AGeV central AuAu 0

38 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Low mass vector mesons invariant mass spectra electrons: pt > 0.2 GeV/c background dominated by physical sources (75%) muons: intrinsic p>1.5 GeV cut (125 cm Fe absorber), use TOF information background dominated by misidentified muons electrons: 200k eventsbackground events – signal 20k ev. All e + e - Comb. bg ρ e + e - e + e - φ e + e - π 0 γ e + e - π 0 e + e - η γ e + e - m = 14 MeV/c 2 m = 11 MeV/c 2 25 AGeV central AuAu

39 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, electrons: events J/ m = 38 MeV/c 2 ' m = 45 MeV/c 2 J/ and ' invariant mass spectra electrons: p 1 GeV, 1 interaction target (25 m Au) muons: 225 cm Fe absorber, no pt-cut muons: events J/ m = 22 MeV/c 2 ' m = 33 MeV/c 2 25 AGeV central AuAu

40 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, CBM – high B, moderate T: searching for the landmarks of the QCD phase diagram first order deconfinement phase transition chiral phase transition QCD critical endpoint characterizing properties of baryon dense matter in medium properties of hadrons? in A+A collisions from AGeV (s NN = 4.5 – 9.3 GeV) starting in 2015

41 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, CBM collaboration Russia: IHEP Protvino INR Troitzk ITEP Moscow KRI, St. Petersburg China: CCNU Wuhan USTC Hefei Croatia: University of Split RBI, Zagreb Portugal: LIP Coimbra Romania: NIPNE Bucharest Poland: Krakow Univ. Warsaw Univ. Silesia Univ. Katowice Nucl. Phys. Inst. Krakow LIT, JINR Dubna MEPHI Moscow Obninsk State Univ. PNPI Gatchina SINP, Moscow State Univ. St. Petersburg Polytec. U. Ukraine: Shevchenko Univ., Kiev Univ. Münster FZ Rossendorf GSI Darmstadt Czech Republic: CAS, Rez Techn. Univ. Prague France: IPHC Strasbourg Germany: Univ. Heidelberg, Phys. Inst. Univ. HD, Kirchhoff Inst. Univ. Frankfurt Univ. Mannheim Hungaria: KFKI Budapest Eötvös Univ. Budapest India: Aligarh Muslim Univ., Aligarh IOP Bhubaneswar Panjab Univ., Chandigarh Univ. Rajasthan, Jaipur Univ. Jammu, Jammu IIT Kharagpur SAHA Kolkata Univ Calcutta, Kolkata VECC Kolkata Univ. Kashmir, Srinagar Banaras Hindu Univ., Varanasi Korea: Korea Univ. Seoul Pusan National Univ. Norway: Univ. Bergen Kurchatov Inst. Moscow LHE, JINR Dubna LPP, JINR Dubna 51 institutions, > 400 members Dresden, September 2007 Cyprus: Nikosia Univ.

42 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, additional slides

43 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, STS R&D 4" 280 µm Microstrip SensorsTracking Stations layout studies module design

44 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, fast self-triggered readout electronics NXYTER chip produced; DETNI GSI test system under construction micro- strip sensor

45 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Sequential dissociation of charmonium? Quarkonium dissociation temperatures – Digal, Karsch, Satz (J/)/DY = L = 3.4 fm Preliminary! [NA60]

46 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, elliptic flow v 2 : initial overlap eccentricity particle azimuthal distributions Collective flow 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! central midcentral peripheral [NA49, PRC68, (2003)] v2v2

47 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, K/ fluctuations 2nd order phase transition at the critical point fluctuations expected measure e.g. particle ratios (K/ ) event-by-event and compare to an event average increase of K/ fluctuations for lower energies observed interpretation open

48 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Even charm quarks flow! even charm quarks participate in the flow!

49 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Relation to EOS maximum 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 center try to use constraints on EOS from A+A collisions! Grigorian, Blaschke, Klähn, astro-ph/

50 Claudia Höhne Seminar des Instituts für Kernphysik, Mainz, Detector R&D – RPC main issue for many detectors: high rates! RPC development together with HADES, FOPI upgrades study different materials! R&D HADES


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