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Probing dense baryonic matter with time-like photons

Probing dense baryonic matter with time-like photons. Dilepton spectroscopy from 1 to 40 A GeV at GSI and FAIR Joachim Stroth Univ. of Frankfurt. First chance collisions. Dense matter. Freeze-out. Toneev et al., 2004. The physics case. What are the properties of dense nuclear matter?.

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Probing dense baryonic matter with time-like photons

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  1. Probing dense baryonic matter with time-like photons Dilepton spectroscopy from 1 to 40 AGeV at GSI and FAIR Joachim Stroth Univ. of Frankfurt ICPAGQP 2005, Kolkata

  2. First chance collisions Dense matter Freeze-out Toneev et al., 2004 The physics case What are the properties of dense nuclear matter? Its macroscopic properties depend on the microscopic structure! ICPAGQP 2005, Kolkata

  3. J. Wambach et al. Densebaryonic matter The physics case Probe the electromagnetic structure of (hot) and dense nuclear matter in the time-like region! • What is the relevant excitation spectrum as the matter density increases? • Where are the limits of hadronic existence? Partial restoration of chiral symmetry Additional self-energy terms due to meson-baryon coupling ICPAGQP 2005, Kolkata

  4. n  p p  ++ e+ r K e- Probing the interior of compressed matter Low-mass vector mesons In-medium spectral functions ICPAGQP 2005, Kolkata

  5. The HADES spectrometer • Geometry • Full azimuth , polar angles 18o - 85o • Pair acceptance  0.35 • About 80.000 detector channels • Fast particle identification • RICHCsI solid photo cathode, No 80, C4F10 radiator • TOF (Scintillator rods) • TOFino (Scintillator paddles) temporary solution, RPC in future • Pre-Shower18 pad chambers & lead converters • Momentum measurement • ILSE, super conducting toroid Br = 0.35 Tm • MDC Multi-wire drift chamber, single cell resolution  100 mm 1 m ICPAGQP 2005, Kolkata

  6. ICPAGQP 2005, Kolkata

  7. Experimental runs • November 2001: commissioning run target = 5% • C+C 2 AGeV LVL1 triggered events (Mch.>3) : 45 Mevents • C+C 1 AGeV LVL1 trigger : 7.3 Mevents • full coverage with inner MDC chambers (Dp/p  10% at 0.7 GeV/c) • November 2002: C+C 2 AGeV, commissioning and physics runs • target= 2 x 2.5%, 56% LVL1 trigger + 44% LVL2 trigger 220 Mevents • 6 outer drift chambers (MDC) in 4 sectors • October 2003: p+p commissioning run (1 GeV, 2 GeV) • full coverage with outer MDC III (4 MDC IV) (Dp/p  1.5 % at 0.7 GeV/c) • February 2004: p+p 2GeV production run • target 5 cm l-H2 400 Mevents • August 2004: C+C 1AGeV production run • 3x1.5 % target, 56% LVL1 trigger + 44% LVL2 trigger650 Mevents ICPAGQP 2005, Kolkata

  8. Fast 2nd level trigger up to 20 kHz LVL1Fast multiplicity trigger full event information digitised. on-line selection of electron candidates Suppression 10 - 100 LVL2 triggered events are transported to mass storage ICPAGQP 2005, Kolkata

  9. Scaled down by 9.2 ! LVL2 LVL1 Yield /event [a.u] e+e->40 Me+e- [MeV/c2] On-line off-line comparison • Trigger condition used in November 2002 run: • At least one good electron candidate • Ring matched with META hit • Data rate reduced by 92 % • Pair enhancement by factor of  9 • Single lepton efficiency of IPUs + matching  62%(pairs 82%) No bias on data ICPAGQP 2005, Kolkata

  10. C+C @ 2 A GeV "Nov’02" No Efficiency / Acceptance Correction preliminary • Minimal tracking analysis • No in-medium contributions in the simulation. ICPAGQP 2005, Kolkata

  11. C+C @ 1 A GeV “Aug'04” No Efficiency / Acceptance Correction All N+- B+- = 2*sqrt(N++*N--) S+- = N+- - B+- very preliminary Yield / 1 MeV/c2 M [MeV/c2] ICPAGQP 2005, Kolkata

  12. e+ 208Pb -  n e- Meson-baryon coupling and in-medium spectral functions One possible scenario Starting in 2006! • Precision spectroscopy at nuclear ground state density • Invariant mass resolution with outer tracking is 1 % in the vector meson mass region W.Schoen et al. Acta Phys.PolB27(1996)2959 M. Effenberger, Giessen ICPAGQP 2005, Kolkata

  13. Facility for Antiproton and Ion Research FAIR nuclear matter at high densities CBM experiment Staged realization ICPAGQP 2005, Kolkata

  14. The future of dielectron spectroscopy at FAIR Heavy ion collisions at interaction rates of up to 107 Hz and beam energies from 2 to 40 GeV/u CBM Detector E > 10 AGeV Talk by Peter Senger on Wednesday HADES E < 10 AGeV ICPAGQP 2005, Kolkata

  15. pt e+ e- e+ e- 0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3 Y HADES acceptance at higher energies Simulation C+C 2 AGeV C+C 8 AGeV Ycm Ycm Ycm Ycm 1 GeV/c ThermalSource 1 GeV/c Accepted Electrons from: po-Dalitz, h-Dalitz, r, w (-Dalitz), f 40 % of geometrical cross section J. Novotny, HADES collaboration meeting 2003 ICPAGQP 2005, Kolkata

  16. HADES with beam from SIS100 Simulation Compared to 2 A GeV • acceptance 40% lower • yields 2 orders of magnitude higher ICPAGQP 2005, Kolkata

  17. Experimental concept Perform momentum measurement in a 1m3 volume with 1 T magnetic field. Possibly a flexible configuration to optimize performance for different physics cases.. Both options, electrons and muons are investigated. High quality tracking to identify "background" tracks (conversion, p0) Detector configuration CBM experiment ICPAGQP 2005, Kolkata

  18. HADES HADES++ CBM Dilepton spectroscopy at GSI and FAIR • Final C+C spectra 1 and 2 AGeV • p, p, d, A on lH2, A • A+A heavy collision systems 2005 • A+A medium up to 8-10 AGeV 2010 • Dilepton spectroscopy in A+A at 10-40 AGeV time [year AC] 2015 Systematic study of the microscopic properties of dense baryonic matter ICPAGQP 2005, Kolkata

  19. Cyprus University of Cyprus France Institut de Physique Nucléaire d'Orsay Czech Republic Nuclear Physics Institute, Rez Czech Academy of Sciences, Rez Germany GSI, Darmstadt FZR, Dresden Johann Wolfgang Goethe-Universität Frankfurt Justus Liebig Universität Giessen Technische Universität München Italy INFN Catania Università di Catania INFN Milano Università di Milano Poland Jagiellonian University of Cracow Russia LHE at JINR, Dubna Institute for Nuclear Research, Moscow MEPHI, Moscow ITEP, Moscow Spain University of Santiago de Compostela Universidad de Valencia-CSIC The Collaboration ICPAGQP 2005, Kolkata

  20. The CBM Collaboration 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. Marburg 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 LIT, JINR Dubna Obninsk State Univ. PNPI Gatchina SINP, Moscow State Univ. St. Petersburg Polytec. U. Spain: Santiago de Compostela Univ. Ukraine: Shevshenko Univ. , Kiev Univ. of Kharkov Hungaria: KFKI Budapest Eötvös Univ. Budapest Korea: Korea Univ. Seoul Pusan National Univ. Norway: Univ. Bergen Poland: Krakow Univ. Warsaw Univ. Silesia Univ. Katowice Portugal: LIP Coimbra Romania: NIPNE Bucharest ICPAGQP 2005, Kolkata

  21. linear z axis ! log. z axis ! yield [arb. units] Lepton candidate selection Events with lepton multiplicity  1 in LVL1 triggered events: 1.2 % • Require META and RICH signal (LVL2) • + matching with fully reconstructed tracks cut on b ICPAGQP 2005, Kolkata

  22. Signal to Background Nov02 preliminary C+C Nov ‘02 S/B data simulation Ne+e- - CB S/B = CB <S/B> ~ 4:1 (M < 100 MeV/c2) <S/B> ~ 1:2 (M > 100 MeV/c2) inv. mass [MeV/c2] ICPAGQP 2005, Kolkata

  23. Dielectrons in CBM R. Karabowicz, Kraków, CBM Collaboration Meeting ICPAGQP 2005, Kolkata

  24. pp->ppX Ethresh [GeV]  /  -p->Xn  Mx [GeV/c2] Experiments with pion beams • in-beam tracking of pions • pp and pA reactions ICPAGQP 2005, Kolkata

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