1 / 33

Schwerionen- und Hadronenphysik an und

Schwerionen- und Hadronenphysik an und. Claudia Höhne, GSI Darmstadt. Einleitung GSI FOPI & HADES FAIR HADES & CBM Zusammenfassung & Ausblick. KHuK Jahrestagung, 25./26.10.2007, GSI Darmstadt. The QCD phase diagram. aim of heavy ion physics explore the QCD phase diagram!

hester
Télécharger la présentation

Schwerionen- und Hadronenphysik an und

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Schwerionen- und Hadronenphysik anund Claudia Höhne, GSI Darmstadt • Einleitung • GSI FOPI & HADES • FAIR HADES & CBM • Zusammenfassung & Ausblick KHuK Jahrestagung, 25./26.10.2007, GSI Darmstadt

  2. The QCD phase diagram • aim of heavy ion physics • explore the QCD phase diagram! • study hadronic properties at high baryon densities • chiral symmetry restoration? CBM@FAIR A+A collisions at 10 – 45 GeV/nucleon HADES@FAIR A+A collisions at 2-10 GeV/nucleon [Andronic et al. Nucl. Phys. A 772, 167 (2006). FOPI & HADES @GSI A+A collisions at < 2 GeV/nucleon

  3. The SIS18 heavy ion regime ≈ 10 fm/c 30 10 20 t [fm/c] • Probing nuclear matter at “moderate" baryon density and temperature • A long life time of the dense system (up tp 10 fm/c) • The all-dominant presence of baryonic resonances (“resonance matter”), Np/Apart ≈ 10% • The sub-threshold production of Kaons and Vector Mesons: Multi-step processes confined to the dense phase

  4. Kaons in medium Modified properties of hadrons in dense baryonic matter? → mass, width, phase-space and angular distributions repulsive K+ N potential in-medium kaon energy ↔ equation of state in dense matter? attractive K- N potential (yellow area: envelope of several microscopic calculations: all predict the same trend !)

  5. FOPI – strangeness @ SIS • Motivation • hadronic properties in dense medium (1-3 r0)? • strangeness! (production close to threshold) • → sensitive probe! • Kaons in medium • yields, phase space distributions, flow • Strange Resonances • Baryons! Excited hyperon S*(1385) • → total strangeness, thermalisation? • Exotica – kaonic bound states IPNE Bucharest, Romania ITEP Moscow, Russia CRIP/KFKI Budapest, Hungary Kurchatov Institute Moscow, Russia LPC Clermont-Ferrand, France Korea University, Seoul, Korea GSI Darmstadt, Germany IReS Strasbourg, France + IMP Lanzhou, China FZ Rossendorf, Germany Univ. of Heidelberg, Germany + SMI Vienna, Austria Univ. of Warsaw, Poland RBI Zagreb, Croatia + TUM, Munich, Germany

  6. Kaon – flow measurements Ni+Ni @ 1.93 AGeV Y.J.Kim (FOPI) directed flow: elliptic flow: Sensitivity of collective flow to depth of kaon potential → U(K+) = + 20 MeV, For K- no consistent description yet by transport models: HSD ↔ IQMD

  7. Strange resonances • for investigation of total strangeness production baryons (L!) are important! • → test thermalization/ chemical equlibrium with statistical model • short lived resonances (e.g. S*) are expected to be also sensitive to dense medium! S*   +  (88  2%) G = 39.4 MeV ct = 5 fm S* in-medium: Γ= 76 MeV at ρ= ρ0 Mean mass: attractive potential ≈ - 45 MeV at ρ0 S*(1385) subthreshold production, X. Lopez et al. (FOPI collaboration), submitted to PRL (2007) • due to short lifetime S* should probe finite density! • Broadening of the width not yet observed (needs more statistics)

  8. FOPI TOF upgrade completed! FOPI – RPC detector: 4500 electronic channels, 6m2 active area

  9. Online performance from 1. experiment (Sep.2007) pp>0.5GeV/c p K+ p+ P (GeV/c) p- Dt = tmeas – ttracking (ns) v (cm/ns) K+ - identification by momentum – TOF analysis up to plab=1GeV/c System time resolution estimate from fast pions: st = 100 ps

  10. Summary of FOPI physics program (2008 – 2010) 2008 (S338): Heavy ion reactions Ru + Ru @ 1.7 AGeV, 4 weeks Strange resonance production Ni + Pb @ 2 AGeV, 2 weeks and flow  K- - potential 2009 (S339): Pion induced reactions p- + LH2, C, Pb @ 1.7 GeV/c, 2 weeks Strangeness production K- - potential at r = r0 2010 (S349): Proton induced reactions p + p @ 3 GeV, 2 weeks Search for ppK- - bound state (accepted proposals by G-PAC)

  11. In-medium properties of hadrons (electromagnetic-probes)  r  e+, μ+ e-, μ- • r-meson couples to the medium, direct radiation from the early phase • vector-meson dominance! • vacuum lifetime t0 = 1.3 fm/c → dileptons = penetrating probe • connection to chiral symmetry restoration? n  p p ++ r-meson spectral function [Rapp, Wambach, Adv. Nucl. Phys. 25 (2000) 1, hep-ph/9909229]

  12. HADES • High Acceptance DiElectron Spectrometer • Focus on the spectroscopy of vector mesons (r, w, f) • Consistent picture in pp, pA, pA and AA reactions • Supplemented by hadron spectroscopy, incl. K0s, L, F • Instrumental challenge! - r,w,f→ e+e- rare probe: 1 e+e- decay from vector mesons per 1-10 Million reactions! • Large background from conversion and p0-Dalitz decay • Spectrometer with a … • High geometric acceptance & invariant mass resolution • High background rejection & rate capability, dedicated LVL2 trigger

  13. Dileptons from C+C preliminary • excess of dilepton yield above cocktail! • relative excess for 1 GeV/nucleon is larger than for 2 GeV/nucleon • shape of relative excess similar [HADES, PRL 98, 052301 (2007)] "cocktail A" = p0 + h + w (long lived)

  14. Quantitative analysis: deduce the absolute excess yield Yexc (beyond η), making use of the TAPS η data: Dileptons from C+C (II) preliminary Yexc(2.0)/Yexc(1.0) = 2.3 ± 0.6(stat) ± 1.0(sys) • HADES confirms DLS! • excess (beyond η) scales like pions • → importance of resonances! • discussions ongoing C + C 2 AGeV Phys. Rev. Lett. 98, 052302 (2007)

  15. Comparison to DLS preliminary • extrapolation of HADES data to DLS acceptance • theory is challenged to explain data! DLS data (C+C, 1AGeV) confirmed by HADES! DLS Data: R.J. Porter et al.: PRL 79(97)1229

  16. Comparison HSD - HADES • comparison of HADES data to HSD (new version including new isospin dependent Bremsstrahlung) • lively discussions ongoing! • → compare to p+p and p+n data! • HADES strategy: • establish experimental "cocktail" of long and short lived e+e- pairs from pp and pn data • (s<sthres for h production) • study exclusive channels (e.g. D+) in pp by missing mass spectroscopy [E. Bratkovskaya, priv. comm.]

  17. p+p, d+pe+e- X, 1.25 GeV Preliminary not efficiency corrected spectrum Online spectrum (data from May 2007 ) preliminary preliminary 100% statistic analyzed : 38877 signal pairs, 607 for M>150 MeV/c2 50% statistic analyzed: 37800 signal pairs, 1230 for M>150 MeV/c2

  18. HADES schedule "DLS puzzle"  elementary reactions! exclusive channels p-beam! chiral symmetry restoration for r=r0 in controled system heavy systems!

  19. HADES upgrade for heavier systems • RPC (TOF with higher granularity, 80ps time resolution) • DAQ (LVL1 rates beyond 30 KHz) HADES at FAIR

  20. High density matter at FAIR • higher energies (2-45 GeV/nucleon) → higher baryon densities, temperatures, energy densities created; but still over time span of 5-10 fm/c • discovery potential: 1st order deconfinement phase transition? critical point? chiral phase transition? • CBM • rare probes! • (charm, dileptons) • sensitive to medium • ... and bulk properties • aim for microscopic • understanding [Bratkovskaya et al., PRC 69 (2004) 054907] UrQMD calculation of T, mB as function of reaction time (open symbols – nonequilibrium, full symbols – appr. pressure equilibrium)

  21. Charm production at threshold • do c and c quarks behave differently in baryon-rich matter? • charmonium (cc) in hot and dense matter? • relation to deconfinement? • 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! [W. Cassing et al., Nucl. Phys. A 691 (2001) 753] HSD simulations

  22. CBM: Physics topics and Observables • The equation-of-state at high B • collective flow of identified hadrons • particle production at threshold energies (open charm) • Deconfinement phase transition at high B • excitation 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 endpoint • excitation function of event-by-event fluctuations (K/π,...) • Onset of chiral symmetry restoration at high B • in-medium modifications of hadrons (,, e+e-(μ+μ-), D) • mostly new measurements • CBM Physics Book (theory) in preparation

  23. CBM collaboration China: CCNU Wuhan USTC Hefei Croatia: University of Split RBI, Zagreb Univ. Münster FZ Rossendorf GSI Darmstadt Korea: Korea Univ. Seoul Pusan National Univ. Russia: IHEP Protvino INR Troitzk ITEP Moscow KRI, St. Petersburg Hungaria: KFKI Budapest Eötvös Univ. Budapest Norway: Univ. Bergen Kurchatov Inst. Moscow LHE, JINR Dubna LPP, JINR Dubna Poland: Krakow Univ. Warsaw Univ. Silesia Univ. Katowice Nucl. Phys. Inst. Krakow Cyprus: Nikosia Univ. 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 LIT, JINR Dubna MEPHI Moscow Obninsk State Univ. PNPI Gatchina SINP, Moscow State Univ. St. Petersburg Polytec. U. Czech Republic: CAS, Rez Techn. Univ. Prague France: IPHC Strasbourg Portugal: LIP Coimbra Romania: NIPNE Bucharest Germany: Univ. Heidelberg, Phys. Inst. Univ. HD, Kirchhoff Inst. Univ. Frankfurt Univ. Mannheim Ukraine: Shevchenko Univ. , Kiev 51 institutions, > 400 members Dresden, September 2007

  24. The CBM experiment MVD + STS • tracking, momentum determination, vertex reconstruction: radiation hard silicon pixel/strip detectors (STS) in a magnetic dipole field • hadron ID: TOF (& RICH) • photons, p0, h: ECAL • PSD for event characterization • high speed DAQ and trigger (up to 10 MHz int. rates) → rare probes! • electron ID: RICH & TRD •  p suppression  104 • muon ID: absorber + detector layer sandwich •  move out absorbers for hadron runs ... measuring both channels would be the best crosscheck of results we can ever do!

  25. STS tracking – heart of CBM Challenge: high track density  600 charged particles in  25o • Task • track reconstruction: • 0.1 GeV/c < p  10-12 GeV/c • Dp/p ~ 1% (p=1 GeV/c) • primary and secondary vertex reconstruction (resolution  50 mm) • V0 track pattern recognition silicon pixel and strip detectors D+→ p+p+K- (ct = 317 mm) D0 → K-p+ (ct = 124 mm) → drives CBM layout!

  26. STS and FEE R&D Fast self-triggered readout chip n-XYTER in collaboration with DETNI prospect: CBM-XYTER Strip sensor development with CIS Erfurt First test sensor delivered spring 2007

  27. 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)

  28. 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 resolution • proton identification with TOF 1012 central Au+Au collisions, 25 AGeV

  29. Low mass vector mesons 25 AGeV central AuAu All e+e- Comb. bg ρe+e-  e+e-φe+e- π0 γe+e-  π0e+e-ηγe+e- • 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 electrons: 200k events background 4 ∙108 events – signal 20k ev. w,fsm = 14 MeV/c2 w,fsm = 11 MeV/c2

  30. J/y and y' 25 AGeV central AuAu electrons: 2.4 ∙1010 events J/ysm = 38 MeV/c2 y' sm = 45 MeV/c2 • invariant mass spectra • electrons: p < 11 GeV/c, pt > 1 GeV, 1‰ interaction target (25 mm Au) • muons: 225 cm Fe absorber, no pt-cut muons: 4 ∙108 events J/ysm = 22 MeV/c2 y' sm = 33 MeV/c2

  31. Summary & Outlook • succesful investigation of hadronic matter at moderate densities (1-3 r0) • data on elementary interactions and serious theoretical effort essential! • FOPI → sensitivity of kaons to dense medium demonstrated • → quantify medium modifications for strange hadrons • → multi-strange clusters? • HADES → "DLS puzzle" solved • → setup completed, production phase of high quality data • → broad program (e.g. p,p+A, Au+Au), upgrade and move to FAIR • investigate high baryon density region of QCD phase diagram (deconfinement phase transition, chiral symmetry restoration) • CBM → comprehensive investigation including rare probes • (dileptons and charm) • → detailed simulations, R&D ongoing • complementary effort to LHC

  32. Backup

  33. Vector Mesons: p+p, 3.5 GeV May 2007, preliminary, online results! No final calibration/alignment! Hadron analysis: missing mass technique: pp 4-prong (+++-)-selection <2% of statistics pppp+0- ppppK+K- e+e- pair analysis: w not shifted! Preliminary calibration… Extra yield below VM pole mass. 10 S/B Yiel (a.u.) ppppK+K- 1 0.5 1.0 Mee w Preliminary η yield (a.u.) pp missing mass (GeV/c2) pppp+0- pp missing mass (GeV/c2) PRELIMINARY

More Related