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Strangeness Production in Ar+KCl Reactions with HADES

Strangeness Production in Ar+KCl Reactions with HADES. Experiment Overview. Data taking in September/October 2005 Ar+KCl @ 1.756 AGeV 10 TB raw data (4200 files) 6.9*10 8 events used for analysis Multiplicity 18 trigger (LVL1) selected 35% most central reactions. Analysis Overview.

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Strangeness Production in Ar+KCl Reactions with HADES

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  1. Strangeness Production in Ar+KCl Reactions with HADES Experiment Overview • Data taking in September/October 2005 • Ar+KCl @ 1.756 AGeV • 10 TB raw data (4200 files) • 6.9*108 events used for analysis • Multiplicity 18 trigger (LVL1) • selected 35% most central reactions Analysis Overview • Particle identification of • using various information of the detectors Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  2. HADES Setup High Acceptance Di-Electron Spectrometer HADES @ SIS/GSI • Polar angle coverage: 18° < Q < 88° • Azimuthal angle coverage: 0° < f < 360° • 24 multi-wire drift-chambers in 4 planes • 2 time-of-flight walls (TOF/TOFino) • Superconducting toroid • RICH and preSHOWER for e+e--PID side view Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  3. PID using Time of Flight and dE/dx MDC TOF (44° < Q < 88°) Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  4. Beta vs. Momentum (Kaons) • K+ and K- - mesons can be • identified in the TOF region up to a • momentum of 1000 MeV/c • Due to the lower resolution in the • TOFino detector the identification • is limited to <600 MeV/c Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  5. Vertex-cuts • Inner drift-chambers are used • for vertex reconstruction • Primary vertex resolution: • Background reduction for • identification • Vertex position important for • mixed-event analysis Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  6. K0S-Mesons • 51.000 reconstructed -mesons • in the channel • S/B 1.0 • MeV/c2 Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  7. L-Hyperons • 145.000 reconstructed -hyperons • in the channel • S/B 0.3 • MeV/c2 Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  8. f-Mesons • 168 reconstructed -mesons • in the channel • S/B 1.1 • MeV/c2 Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  9. K0S Invariant Mass (mt) Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  10. L Invariant Mass (mt) Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  11. mt-spectra of L and K0S Boltzmann representation: Rapidity densitiy: Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  12. Kaons phase space distribution K+-Mesons K--Mesons Diploma thesis M. Lorenz Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  13. mt-spectra of charged kaons • Due to the lower resolution of the TOFino detector, only kaons • in the TOF-region were used for analysis • Still a phase-space coverage of one half of the rapidity distribution Diploma thesis M. Lorenz Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  14. f invariant mass (mt) and mt-spectra First measurement of a f-temperature at SIS energies! Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  15. Proton-Pion mt-spectra Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  16. Pion Rapidity Distributions Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  17. Proton Rapidity Distributions Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  18. Rapidity distributions of L-hyperons and K0S -mesons Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  19. Rapidity distributions of kaons Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  20. Rapidity distribution of f-mesons • Assumption of a symmetric and thermal distribution with width: • Variation of the data point inside the bin range gives systematic errors Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  21. Results of Particle Production Strangeness balance and S-production f/K--ratio Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  22. Phi-Meson Production f/K- -ratio becomes larger than 1 at SIS energies E. Bratkovskaya et al. Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  23. Teff as a function of particle mass Ni+Ni @ 1.93 AGeV (FOPI) Ni+Ni @ 1.93 AGeV (KaoS) All Ar+KCl @ 1.756 AGeV (HADES) Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  24. Summary • The MDC-dE/dx information was used for PID • and background suppression • 250.000 K+-meson, 145.000 L-hyperons, • 51.000 K0S-mesons, 6000 K--mesons and • 168 f-mesons were reconstructed • Corrected transverse mass spectra, rapidity- • and TB-distributions of K+, K-, K0S , L , f were presented • The production of S-hyperons was estimated from the • strangeness balance • The f/K--ratio is much higher compared to ultra-relativisitc • energies HADES can be used as a high resolution and high acceptance hadron spectrometer Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  25. Outlook Heavy strange resonances: Kaonic nuclear clusters: R. Kotte, FZ Rossendorf and HADES! Laura´s talk Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  26. HADES Collaboration G. Agakishiev8, C. Agodi1, A. Balanda3,e, G. Bellia1,a, D. Belver15, A. Belyaev6, A. Blanco2, M. Böhmer11, J. L. Boyard13, P. Braun-Munzinger4, P. Cabanelas15, E. Castro15, S. Chernenko6, T. Christ11, M. Destefanis8, J. Díaz16, F. Dohrmann5, A. Dybczak3, T. Eberl11, L. Fabbietti11, O. Fateev6, P. Finocchiaro1, P. Fonte2,b, J. Friese11, I. Fröhlich7, T. Galatyuk4, J. A. Garzón15, R. Gernhäuser11, C. Gilardi8, M. Golubeva10, D. González-Díaz4, E. Grosse5,c, F. Guber10, M. Heilmann7, T. Hennino13, R. Holzmann4, A. Ierusalimov6, I. Iori9,d, A. Ivashkin10, M. Jurkovic11, B. Kämpfer5, K. Kanaki5, T. Karavicheva10, D. Kirschner8, I. Koenig4, W. Koenig4, B. W. Kolb4, R. Kotte5, A. Kozuch3,e, F. Krizek14, R. Krücken11, W. Kühn8, A. Kugler14, A. Kurepin10, J. Lamas-Valverde15, S. Lang4, J. S. Lange8, L. Lopes2, L. Maier11, A. Mangiarotti2, J. Marín15, J. Markert7, V. Metag8, B. Michalska3, D. Mishra8, E. Morinière13, J. Mousa12, C. Müntz7, L. Naumann5, R. Novotny8, J. Otwinowski3, Y. C. Pachmayer7, M. Palka4, Y. Parpottas12, V. Pechenov8, O. Pechenova8, T. Pérez Cavalcanti8, J. Pietraszko4, W. Przygoda3,e, B. Ramstein13, A. Reshetin10, M. Roy-Stephan13, A. Rustamov4, A. Sadovsky10, B. Sailer11, P. Salabura3, A. Schmah4, R. Simon4, S. Spataro8, B. Spruck8, H. Ströbele7, J. Stroth7,4, C. Sturm7, M. Sudol4, A. Tarantola7, K. Teilab7, P. Tlusty14, M. Traxler4, R. Trebacz3, H. Tsertos12, I. Veretenkin10, V. Wagner14, H. Wen8, M. Wisniowski3, T. Wojcik3, J. Wüstenfeld5, S. Yurevich4, Y. Zanevsky6, P. Zumbruch4 Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  27. Backup slides Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  28. TOFino PID and RPC New RPC-detector (beam 2007) TOFino (18° < Q < 45°) Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  29. PID using TOF/TOFino-dE/dx TOFino (18° < Q < 45°) TOF (44° < Q < 88°) Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  30. Kaon Temperature and K-/K+-Ratio Diploma thesis M. Lorenz Teff and K+/K--ratio fits to the systematics of FOPI and KaoS results Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  31. Statistics of Reconstructed Particles Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  32. Mass-Spectra and PID using MDC dE/dx MDC I MDC II MDC III MDC IV particle track • Correction of the ToT-signal for various track topologies • Transformation from ToT to dE/dx, normalized to Bethe-Bloch • Truncated mean is calculated from all measurements of a track Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  33. PID using MDC-dE/dx MDC I MDC II MDC III MDC IV particle track • Correction of the ToT-signal for various track topologies • Transformation from ToT to dE/dx, normalized to Bethe-Bloch • Truncated mean is calculated from all measurements of a track Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  34. Primary Vertex reconstruction • New alignment procedure • for all detectors • Primary vertex resolution: • Important for mixed- event • technique Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

  35. Strangeness Production in Ar+KCl Reactions with HADES • HADES setup and experiment overview • Particle identification using various detectors • Reconstruction of • Transverse mass spectra and rapidity distributions • Particle multiplicities and results Alexander Schmah – GSI/FIAS/TU-Darmstadt Strangeness Workshop/GSI Darmstadt 2008

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