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Study of quark - gluon plasma production at the ALICE detector, CERN

Chinorat Kobdaj SPC 2012 11 May 2012. Study of quark - gluon plasma production at the ALICE detector, CERN . What is heavy ion physics? What is ALICE?. q uark. Found in proton and neutron Bound by strong force Mediated by exchanging gluons No free quark has been observed (confinement).

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Study of quark - gluon plasma production at the ALICE detector, CERN

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  1. ChinoratKobdaj SPC 2012 11 May 2012 Study of quark - gluon plasma production at the ALICE detector, CERN

  2. What is heavy ion physics? • What is ALICE?

  3. quark • Found in proton and neutron • Bound by strong force • Mediated by exchanging gluons • No free quark has been observed (confinement)

  4. quark-gluon plasma (qgp) • at very high temperatures and/or very high densities • Tc≈ 170 MeV ≈ 2000 billion K (compare Sun core: 15 million K)

  5. ~ 10 ms after Big Bang LHC Early Universe RHIC Quark-Gluon Plasma Tc ~ 170 MeV SPS AGS Hadron gas Temperature Nuclear Neutron Star matter ~ 5 - 10 nuclear r Baryon density ec ~ 1 GeV/fm3

  6. How to make qgp? • By colliding two heavy nuclei at a speed close to the speed of light

  7. as the system expands and cools down it will undergo a phase transition from QGP to hadrons again, like at the beginning of the life of the Universe • QGP lifetime ~ a few fm/c

  8. Where can we do it? • at the CERN Large Hadron Collider

  9. What is ALICE? • ALICE (A Large Ion Collider Experiment) • It has been designed to work with a large number of particles obtained form collisions of lead nuclei at the extreme energies of the LHC.

  10. How can we see the qgp? • Strange quarks are not component of the colliding nuclei. • But we have observed some strange quarks in the collision. This is called Strangeness enhancement. • Strange quarks or antiquarks observed have been created from the kinetic energy of colliding nuclei.

  11. K+ s s s s s s s s d d u u d X- u p- u d d d d d d d d d d d s u u u u u u u u s s u d d d d p+ u u s u u u u p u u d d d s W+ u s s u u d d u s d L • Therefore, we look at the strangeness enhancement as a signature for quark gluon plasma

  12. Strange Particles • Strange particles are hadrons containing at least one strange quark. • For example • (d) kaon • Λ (uds) hyperon

  13. V0 decay pattern • The starting particle disappears from the interaction point and two oppositely charged particles appear in opposite directions • → π+π- • Λ→ p + π-

  14. Cascade decays • Ξ-decays into π- and Λ • Then the Λ then decays into π- and proton • Ξ-→π-Λ→ π- p + π-

  15. Bubble chambers – in 2-m CERN hydrogen bubble chamber 1973 Karel Šafařík: ParticleTracking Karel.Safarik@cern.ch 15 30 เม.ย. – 1 พ.ค. 2555

  16. Bubble chambers D* in BEBC hydrogen bubble chamber 1978 Karel Šafařík: ParticleTracking Karel.Safarik@cern.ch

  17. Streamer chamber ++e+ decay in streamer chamber 1984 Karel Šafařík: ParticleTracking Karel.Safarik@cern.ch

  18. Streamer chamber 6.4 TeVSulphur - Gold event (NA35) 1991 Karel Šafařík: ParticleTracking Karel.Safarik@cern.ch

  19. Today there are so many tracks. 2010

  20. How can we do it? • By the help of computer • Simulation software • Interface with the detectors

  21. LHC Computing Grid The data stream from the detectors provides approximately 300 GB/s 27 TB of raw data per day or 10–15 PB of data each year These data is more than any single, current, system can handle Scientists look at a computer screen at the control centre of the CERN in Geneva September 10, 2008. (Xinhua/Reuters Photo)

  22. We need to find the system that can handle massive amounts of data can process large computing jobs relatively inexpensive simple to use can access 24/7 easily upgraded

  23. Why don’t we build a super Computers? very expensive very difficult to access obsolete quickly http://gizmodo.com/298029/worlds-biggest-supercomputer-is-a-virus

  24. Solution: using the Internet ? A Computing Grid GridPP masterclasstalk2009

  25. What is middleware? Middleware is a computersoftware that allows users to submit jobs to the Grid without knowing where the data is or where the jobs will run. The software can run the job where the data is, or move the data to where there is CPU power available.

  26. How to set up LHC GRID site? The basic LCG site consists of UI User Interface CE Compute Element WN Worker Nodes SE StorageElement SiteBDIIBerkley Database Information Index MON Monitor Accountingservice

  27. Operating systemSLC5

  28. Middleware The gLite middleware is produced by the EGEE project.

  29. Computing model at ALICE • Computing framework • Simulation • Reconstruction • Data analysis

  30. Main software • Root • Aliroot • Geant3

  31. ROOT framework

  32. AliRoot framework • Modularity • Re-usability

  33. Event generators : • HIJING • DPMJET • PYTHIA ALICE have developed a generators base class called AliGenerator.

  34. Detector response simulation

  35. Simulation process : • Event generation of final-state particles • Particle transport • Signal generation and detector response • Digitization • Fast simulation

  36. Analysis tools • Statistical tools • Calculations of kinematics variables • Geometrical calculations • Global event characteristics • Comparison between reconstructed and simulated parameter • Event mixing • Analysis of the HLT data • visualization

  37. ALICE Physics Working Group • PWG-PP Detector Performance • PWG-CF Correlations Fluctuations Bulk • PWG-DQ Dileptons and Quarkonia • PWG-HF Heavy Flavour • PWG-GA photon and pion working group • PWG-LF Light Flavour Spectra • PWG-JE Jets • PWG-UD

  38. 1. PWG-PP Detector Performance • Quality Assurance • Calibration • Event Characterization • Particle Identification • Event and Track Selections • Tracking and Alignment • Run Conditions

  39. Embedding and mixing • Monte Carlo

  40. 2. PWG-CF Correlations Fluctuations Bulk • Correlations • Event-by-Event / Fluctuations • Femtoscopy • Flow

  41. 3. PWG-DQ Dileptons and Quarkonia • LmeeLow Mass Dielectron • LmmumuLow Mass Mumu • Jpsi2eeJ/ψ to e+e- at mid-rapidity • Jpsi2mumuJ/ψto Mumu • Upsilon2mumuUpsilon to mumu

  42. * 4. PWG-HF Heavy Flavour • HFEElectrons from HF decays • D2H Fully reconstructed charm hadron decays • HFMMuon from HF decays

  43. 5. PWG-GA photon and pion working group • Gamma and Neutral Pions

  44. 6. PWG-LF Light Flavour Spectra • GEO Global Event Observables • Resonances • Spectra • Strangeness 7. PWG-JE Jets

  45. 8. PWG-UD • Ultraperipheral, Diffractive, Cross section and Multiplicity, and Cosmics • Ultra Peripheral Collisions • Cross section and Multiplicity • Diffraction • Cosmics

  46. Acknowledgement • SuranareeUniversity of Technology • Thailand Center of Excellence in Physics (ThEP) • National Electronics and Computer Technology Center

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