1. Kao, Chung-Wen 高崇文 Chung Yuan Christian University 臺灣中原大學
Kaon and Pion Fragmentation functions and SIDIS off deuteron
Kao, Chung-Wen 高崇文
Chung Yuan Christian University
臺灣中原大學
2016/7/26 Menu 2016

2. How to extract Fragmentation functions?

4. SIDIS off deuteron target
p: proton, n: neutron

5. SIDIS using deuteron target
Charge Conjugation

6. SIDIS using deuteron target
Assume PDFs are charge symmetric:

7. SIDIS using deuteron target
DQ>>DS

8. Constrains on A and B
Since S(x)>0, Q(x)>0, then S(x)/Q(x) is positive!
At fixed x and Q2 :
Note that the values of and are independent of x!

9. HERMES Data of Pion multiplicity

10. Let’s shopping!

11. Choices of FFs

12. Elementary Fragmentation Functions
One step fragmentation process
q(k) →h(p)+Q(k-p)
With a vertex of quark-quark-PS meson, one can calculate the elementary FFs.

13. Elementary Fragmentation functions
One step fragmentation process
q(k) →h(p)+Q(k-p)

14. Nonlocal Chiral quark model
Non-local vertex of
quark-quark-PS meson

15. Inclusion of quark-jet contribution

16. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA 9.DSEHS

17. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA 9.DSEHS

18. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA 9.DSEHS

19. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA 9.DSEHS

20. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA 9.DSEHS

21. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA 9.DSEHS

22. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA 9.DSEHS

23. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA 9.DSEHS

24. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA 9.DSEHS

25. HERMES Kaon Data
A. Airapetian et al. (HERMES Collaboration), Phys. Rev. D , (2014).

26. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08

27. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08

28. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08

29. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08

30. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08

31. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08

32. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08

33. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08

34. HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08

37. Inclusion of error bar

39. Inclusion of error bar

41. Including the error bar

43. Inclusion of error bar

44. Is there inconsistency?
To make sense of our result, we try to figure out the best values of DQ and DS
to fit the HERMES data.
If we assume the values of DQ and DS are not sensitive to Q2 then we only need to plug in PDFs S(x) and Q(x) then we should decide the values of DQ and DS .

45. Best fit values of DQ and DS
DQ<<DS!

46. Best fit values of DQ and DS

47. M.Stolarski (COMPASS Collaboration), in SPIN2014, 21st International Symposium on Spin Physics, Beijing, October 19–24, 2014

48. Best fit values of DQ and DS
DKQ
DKS
DSK<0!

49. Can CSB explain inconsistency?
Assume

50. Can CSB explain inconsistency?

51. Can CSB explain inconsistency?

52. Conclusion
To be consistent with HERMES data, the u quark is more likely to fragment to pion rather than kaon.
S(x)/Q(x) derived from pion and kaon multiplicity of SIDIS are not consistent
with the one from PDFs.
None of fragmentation functions can be used to extract PDFs from HERMES data consistently in the LO analysis.
CSB is unlikely to explain this problem!

53. Outlook: NLO analysis

54. Outlook: NLO analysis
HERMES data is challenge for FF modeling !

55. Thank you for your attention
And hope that I have convince you that it is fun to study SIDIS!