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Modified Fragmentation Function from Quark Recombination

Modified Fragmentation Function from Quark Recombination. Enke Wang (Institute of Particle Physics, Huazhong Normal University) with A. Majumder, X.-N. Wang I. Introduction Quark Recombination and Parton Fragmentation at zero temperature

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Modified Fragmentation Function from Quark Recombination

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  1. Modified Fragmentation Function from Quark Recombination Enke Wang (Institute of Particle Physics, Huazhong Normal University) with A. Majumder, X.-N. Wang I. Introduction • Quark Recombination and Parton Fragmentation at zero temperature • Quark Recombination and Parton Fragmentation in a Thermal Medium • Conclusion Nucl-th/0506040

  2. I. Introduction parton hadrons E ph Fragmentation Function in Vacuum: are measured, and its QCD evolution tested in e+e-, ep and pp collisions Modification of Fragmentation Function in Medium: Jet Quenching Suppression of leading particles

  3. Energy Loss in Cold Nuclear Matter from e-A DIS E. Wang, X.-N. Wang, Phys. Rev. Lett. 89 (2002) 162301

  4. Energy Loss in Hot Medium from Au-Au Collision Energy loss (initial parton density) ~ 30 times larger than that in cold Au nuclei ! PHENIX, Nucl. Phys. A757 (2005) 184

  5. Quark Recombination in intermediate Pt Region Baryon Meson Baryon Meson Intermediate Pt : Quark Recombination R. C. Hwa, C. B. Yang, PRC67 (2003) 034902 V. Greco, C. M. Ko, P. Levai, PRL90 (2003) 202302 R. J. Fries, B. Muller, C. Nonaka, S. A. Bass, PRL90 (2003) 202303

  6. Motivation of the Work How to deal with the quark recombination from the quantum field theory? Is it possible to deal with the jet quenching and the recombination in a unified framework? This Work: Establish the theoretical framework of the quark recombination from the modification of fragmentation function in thermal medium.

  7. II. Quark Recombination and Parton Fragmentation at zero Temperature Single hadron fragmentation function: DGLAP:

  8. Constitutent Quark Model Meson state: Baryon state: Insert them into:

  9. Meson Production from Recombination (T=0) Recombination Probability: Constituent Diquark Distribution Function:

  10. Evolution of Double Constituent Quark Distribution Function Radiative correction to diquark distribution function: DGLAP Equation of diquark distribution function: They have the same form as the single hadron fragmentation function !

  11. Sum Rule for Constituent Quark Distribution Function Single Constituent Quark Distribution Function: Diquark Distribution Function:

  12. III. Quark Recombination and Parton Fragmentation in a Thermal Medium J.Osborne, E.Wang, X.N.Wang PRD67 (2003) 094022 Thermal Average: Single hadron fragmentation at finite T: Difference with that at zero temperature: Depend on initial energy of parton and Temperature T Parton hadronize all together with the medium

  13. “Shower-Shower” & “Shower-Thermal” Modified fragmentation function with energy loss in thermal medium “Shower-Shower” Contribution: “Shower-Thermal” Contribution:

  14. “Thermal-Thermal” Contribution R. Fries, B. Muller, C. Nonaka, S. Bass, PRC68 (2003) 044902

  15. Baryon Production from Quark Recombination + = + +

  16. Fragmentation at extreme high Pt Baryon Meson Extreme high transverse momentum: Fragmentation is dominant

  17. VI. Conclusion • The hadron fragmentation function can be expressed as the convolution of the recombination probability and the constituent quark distribution function. • The DGLAP equation of the constituent quark distribution function is derived. The relation among triquark, diquark and single quark distribution function is obtained through sum rule. • Both thermal-shower recombination and parton energy loss lead to medium modification of parton fragmentation functions • A unified framework for parton energy loss and quark recombination

  18. Thank You

  19. Thermal Average of Matrix Element Shower-Shower Shower-Thermal Thermal-Thermal represents the modified fragmentation function with energy loss and detailed balance in hot medium

  20. Meson Production from Thermal Quark Recombination Meson fragmentation function at finite T:

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