1. Chinorat Kobdaj SPC 2012 11 May 2012

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. Tc ~ 170 MeV  ~ 5 - 10 nuclear Quark-Gluon Plasma Hadron gas Nuclear matter Neutron Star SPS AGS Early Universe LHC RHIC Baryon density Temperature  c ~ 1 GeV/fm 3 ~ 10  s after Big Bang

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.  Therefore, we look at the strangeness enhancement as a signature for quark gluon plasma s u s d ud u u u u u u u u u u u u u u d d d d d d d d dd d d d d s s ss s s s s s s s s s s dd d d d d d u u u u u u u u d K+K+ u ++ ++ -- p  --

12. Strange Particles

13. V0 decay pattern

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

16. 30 เม. ย. – 1 พ. ค. 2555 Karel Šafařík: ParticleTracking Karel.Safarik@cern.ch16 Bubble chambers D* in BEBC hydrogen bubble chamber 1978

17. 30 เม. ย. – 1 พ. ค. 2555 Karel Šafařík: ParticleTracking Karel.Safarik@cern.ch17 Streamer chamber  +  +  e + decay in streamer chamber 1984

18. 30 เม. ย. – 1 พ. ค. 2555 Karel Šafařík: ParticleTracking Karel.Safarik@cern.ch18 Streamer chamber 6.4 TeV Sulphur - Gold event (NA35) 1991

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 computer software thatcomputersoftware 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 Storage Element  Site BDII Berkley Database Information Index  MON Monitor  Accounting service

27. Operating system SLC5

29. Middleware  The gLite middleware is produced by the EGEE project.EGEE

31. Computing model at ALICE  Computing framework  Simulation  Reconstruction  Data analysis

32. Main software  Root  Aliroot  Geant3

33. 33

34. 34 Modularity Re-usability

35. Event generators :  HIJING  DPMJET  PYTHIA ALICE have developed a generators base class called AliGenerator. 35

36. 36

37. Simulation process :  Event generation of final-state particles  Particle transport  Signal generation and detector response  Digitization  Fast simulation 37

38.  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 38

39. ALICE Physics Working Group 1. PWG-PP Detector Performance PWG-PP Detector Performance 2. PWG-CF Correlations Fluctuations Bulk PWG-CF Correlations Fluctuations Bulk 3. PWG-DQ Dileptons and Quarkonia PWG-DQ Dileptons and Quarkonia 4. PWG-HF Heavy Flavour PWG-HF Heavy Flavour 5. PWG-GA photon and pion working group PWG-GA photon and pion working group 6. PWG-LF Light Flavour Spectra PWG-LF Light Flavour Spectra 7. PWG-JE Jets PWG-JE Jets 8. PWG-UD PWG-UD

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

41.  Embedding and mixing  Monte Carlo

42. 2. PWG-CF Correlations Fluctuations Bulk  Correlations Correlations  Event-by-Event / Fluctuations Event-by-Event / Fluctuations  Femtoscopy Femtoscopy  Flow Flow

43. 3. PWG-DQ Dileptons and Quarkonia  Lmee Low Mass Dielectron Lmee  Lmmumu Low Mass Mumu Lmmumu  Jpsi2ee J/ψ to e+e- at mid-rapidity Jpsi2ee  Jpsi2mumu J/ψ to Mumu Jpsi2mumu  Upsilon2mumu Upsilon to mumu Upsilon2mumu

44. * 4. PWG-HF Heavy Flavour  HFE Electrons from HF decays HFE  D2H Fully reconstructed charm hadron decays D2H  HFM Muon from HF decays HFM

45. 5. PWG-GA photon and pion working group  Gamma and Neutral Pions Gamma and Neutral Pions

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

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

48. Acknowledgement  Suranaree University of Technology  Thailand Center of Excellence in Physics (ThEP)  National Electronics and Computer Technology Center