Kaon and Pion Fragmentation
functions and SIDIS off deuteron
Kao, Chung-Wen
Chung Yuan Christian University
In collaboration of
D.-J. Yang,(NTNU,Taiwan)
W.-C.Chang (AS), S-.i. Nam (Pukyong
National University, Korea)
How to extract Fragmentation functions?
SIDIS off deuteron target
p: proton, n: neutron
SIDIS using deuteron target
Charge Conjugation
SIDIS using deuteron target
Assume PDFs are charge symmetric:
SIDIS using deuteron target
Constrains on A and B
Since S(x)>0, Q(x)>0, then S(x)/Q(x) is positive!
At fixed Q2 :
Note that the values of A and B are independent of x!
HERMES Data of Pion multiplicity
1.
2.
3.
4.
HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA 9.DSEHS
Analysis of A and B
Kaon Multiplicity
HERMES Kaon Data
A. Airapetian et al. (HERMES Collaboration), Phys. Rev. D
448 89, 097101 (2014).
1.
2.
3.
4.
HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
M.Stolarski (COMPASS Collaboration), in SPIN2014, 21st International
Symposium on Spin Physics, Beijing, October 19–24, 2014
1.
2.
3.
4.
HKNS (LO)
HKNS (NLO)
DSS (LO)
DSS (NLO)
5.NJL-Jet Model
6.Nonlocal Chiral Quark Model
7.AKK08
8.SMKA
Analysis
HERMES Pion Data:
HERMES Kaon Data:
COMPASS Kaon Data:
Best fit values of A and B
Aπ<Bπ!
Best fit values of A and B
Best fit values of A and B
Bk<0!
Can CSB explain inconsistency?
Assume
Can CSB explain inconsistency?
Can CSB explain inconsistency?
Conclusion




To be consistent with HERMES data, the u
quark is more likely to fragment to pion
rather than kaon.
Only Nonlocal chiral quark model can be
compatible with both HERMES data of pion
and kaon.
But the S(x)/Q(x) derived from pion and
kaon multiplicity of SIDIS are not consistent
with the one from PDFs.
CSB is unlikely to explain this problem!
Outlook: NLO analysis
Outlook: NLO analysis
Analysis will become formidable!