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UrQMD and its Application to Cosmic Rays

UrQMD and its Application to Cosmic Rays. Marcus Bleicher Institut für Theoretische Physik Goethe Universität Frankfurt Germany. In collaboration with H.J. Drescher. Thanks to. Hajo Drescher Sascha Vogel Xianglei Zhu Stephane Haussler Hannah Petersen Diana Schumacher.

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UrQMD and its Application to Cosmic Rays

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  1. UrQMD and its Application toCosmic Rays Marcus Bleicher Institut für Theoretische Physik Goethe Universität Frankfurt Germany In collaboration with H.J. Drescher Marcus Bleicher, VIKHOS Corsika School 2005

  2. Thanks to • Hajo Drescher • Sascha Vogel • Xianglei Zhu • Stephane Haussler • Hannah Petersen • Diana Schumacher Marcus Bleicher, VIKHOS Corsika School 2005

  3. Some history… • IQMD, QMD: non-relativistic models (E< 2 AGeV) • RQMD (first relativistic transport model), developed in Frankfurt. Not supported since 2000 • UrQMD (development started 1996 at Frankfurt) • NOT transport/cascade models: • HIJING • PYTHIA/FRITIOF • NEXUS, VENUS • DPM Marcus Bleicher, VIKHOS Corsika School 2005

  4. The tool: UrQMDv2.2 • Non-equilibrium transport model • Hadrons and resonances • String excitation and fragmentation • Cross sections are parameterized via AQM or calculated by detailed balance • pQCD hard scattering at high energies (not in v1.3) • Generates full space-time dynamics of hadrons and strings Marcus Bleicher, VIKHOS Corsika School 2005

  5. Included Particles Marcus Bleicher, VIKHOS Corsika School 2005

  6. Reaction stages • Initialization of projectile and target (Lorentz contracted Woods-Saxon) • Generate table with collision/decay sequence with • Propagate to next collision • Perform collision according to cross sections - elastic scattering - inelastic scattering - resonance production - soft string formation and fragmentation - pQCD hard scattering / fragmentation • Update particle arrays, update collision table, perform next collisions Marcus Bleicher, VIKHOS Corsika School 2005

  7. Resonance cross sections Marcus Bleicher, VIKHOS Corsika School 2005

  8. Collision Spectrum • Initial baryon-baryon scatterings • Cooking of QCD matter (Thermalization) • Freeze-out stage Marcus Bleicher, VIKHOS Corsika School 2005

  9. Basic checks (I) Marcus Bleicher, VIKHOS Corsika School 2005

  10. Basic Checks (II) Unfortunately the data has poor qualityOne has to rely on the extrapolation This leads to ~10% systematic uncertainty E=21000 AGeV Marcus Bleicher, VIKHOS Corsika School 2005

  11. Au+Au Baryon Stopping Au+AU 160 AGeV 21 ATeV Energy deposition is OK Anything special here? Marcus Bleicher, VIKHOS Corsika School 2005

  12. Pion induced reactions • UrQMD works reasonable Marcus Bleicher, VIKHOS Corsika School 2005

  13. Proton induced reactions Particle production in pA is in line with data in UrQMD Marcus Bleicher, VIKHOS Corsika School 2005

  14. Particle Production at higher energies Marcus Bleicher, VIKHOS Corsika School 2005

  15. Stopping at high energies Marcus Bleicher, VIKHOS Corsika School 2005

  16. Ratio of LDFs p @ 1019 eV LDFs at large distances depend strongly on the low energy model Marcus Bleicher, VIKHOS Corsika School 2005

  17. When to switch from high to low energy model Corsika switches models at E=80 GeV However, even at 200 GeV, SIBYLL and QGSJET under/overestimate the p+A data Marcus Bleicher, VIKHOS Corsika School 2005

  18. Energy dependence • UrQMD and SIBYLL predict similar results up to E=1000 GeV • UrQMD is tested up to 21 ATeV beam energy • Transition to QGSJET/SIBYLL might be better at higher energies (E~1000 GeV) Marcus Bleicher, VIKHOS Corsika School 2005

  19. Why use UrQMD? • It is distributed with Corsika • Its free software i.e.  Check how we did it Compile it with your favorite options on you favorite system • It is checked with accelerator data • It works very well… download from http://www.th.physik.uni-frankfurt.de/~urqmd Marcus Bleicher, VIKHOS Corsika School 2005

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