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Single-spin asymmetry of charm di-jet in longitudinally polarized pp collisions at STAR

Single-spin asymmetry of charm di-jet in longitudinally polarized pp collisions at STAR. Introduction and motivation Reconstruction of W and Z signals Single-spin asymmetry of di-jet Summary and outlook. Orbital Angular Momentum. Introduction and motivation. Nucleons’ spin structure.

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Single-spin asymmetry of charm di-jet in longitudinally polarized pp collisions at STAR

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  1. Single-spin asymmetry of charm di-jet in longitudinally polarized pp collisions at STAR • Introduction and motivation • Reconstruction of W and Z signals • Single-spin asymmetry of di-jet • Summary and outlook

  2. Orbital Angular Momentum Introduction and motivation Nucleons’ spin structure • In naive Quark Model, the nucleon is made up of three quarks, • its spin (½) is carried by the three quarks’ spin. “Spin Crisis” : In 1988, EMC experiment found proton spin carried by quarks’ spin is 20%-30%. • Spin sum rule for nucleon:

  3. Introduction and motivation Longitudinal spin program at RHIC

  4. Leading order diagrams for Introduction and motivation SSA of W bosons

  5. Introduction and motivation SSA of W bosons

  6. Introduction and motivation SSA of W bosons Motivation-----1

  7. Introduction and motivation Reconstruction of W Leptonic channel : Hadronic channel :

  8. Introduction and motivation Leptonic channel

  9. Introduction and motivation Hadronic channel Motivation-----2

  10. Introduction and motivation SSA of di-jet

  11. Reconstruction of W and Z signals UA2 experiment R.Ansari et al [UA2 Collaboration], Phys. Lett. B 186, 452 (1987)

  12. Reconstruction of W and Z signals Fast Simulation of the invariant mass distribution of di-jet in pp collision at STAR. Mass resolution : 5%

  13. Reconstruction of W and Z signals Fast simulation of the invariant mass distribution of charm di-jet in pp collision at STAR. Mass resolution : 5%

  14. Reconstruction of W and Z signals cross section: comparison:

  15. Reconstruction of W and Z signals

  16. Single-spin asymmetry of di-jet SSA of pure W bosons

  17. Single-spin asymmetry of di-jet SSA of di-jet

  18. Single-spin asymmetry of di-jet SSA of charm di-jet

  19. Single-spin asymmetry of di-jet SSA of charm di-jet events & the charge of charm can be determined

  20. Summary and outlook Summary

  21. Summary and outlook Outlook

  22. Thanks!

  23. Backup

  24. Q. X, E. Sichtermann, Z. Liang, PRD 73,2006 Pol. frag. func. model Why DLL of (anti-)lambda in STAR? Longitudinal spin transfer in polarized proton-proton collisions: Theory prediction on polarization of anti-lambda in RHIC energy:

  25. Qinghua Xu for STAR Data sample: Kinetics range: • <pT> ~ 1.3 GeV • <|xF|> ~ 0.0075 • Minbias data from run 2005 • About 3M events

  26. Jet define algorithms: Kt algorithms and cone algorithms See Salam’s talk

  27. RHIC : Relativistic Heavy Ion Collider STAR : The Solenoidal Tracker at RHIC TPC : time projection chamber EMC : E-M calorimeter

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