The Effect of Errors of Fragmentation Functions on the Analysis of Parton Helicity Distribution
Tokyo Tech
1. Motivation2. FF and pPDF Analyses3. Effects of the error of FFs on pPDF analysis4. Summary
ContentsMar. 25, 2007
Y. Imazu, Y. Miyachi, T.-A. Shibata
- 縦偏極パートン分布関数解析に対する、破砕関数の影響 -
1. Motivation
XheNe
XeNe
Polarized Inclusive DIS :
Polarized Semi-Inclusive DIS :
SIDIS Asymmetry
How large is the effect?The error of FFs could affect the determination of q.⊿
Fragmentation functions (FFs) are important elements in SIDIS asymmetry.
Fragmentation Functions (FFs) :← determined by pQCD analysis of hadron productions in e+ e - collision
I estimated the errors of FFs based on Ktetzer parameterization
Universality
“ Kretzer ” : Phys. Rev., D62, (2000) 054001“ KKP ” : Nucl. Phys., B582, (2000) 514,
Analysis including SIDIS data from SMC and HERMES
- Brute force method for the convolution integrals in x and z.- Analysis with inclusive data converged and are consistent with other pPDF QCD analysis - LO analysis ( reported in Spring 2006 )- NLO analysis was carried out.
Error estimation of FF- Statistical error estimation for Kretzer-FF ( reported in Autumn 2006)
2. pPDF and FF Analyses
0.1 10.01
Expe
rimen
t
Theo
ry
XheNe �
NLOSemi-inclusive DIS
: Error from fit ( χ2⊿ =1 )
With the assumption of SU(3) symmetric sea, motivated by D. de Florian et al. (DNS05): Phys. Rev. D71, (2005) 094018
Results of NLO q analysis with SIDIS data with central values of my FFs⊿Parton Helicity Distributions
to obtain well-defined error bands; well converged covariant matrix
⊿u = 0.85±0.05 d = -0.41±0.13 sea = -0.07±0.04 g = 0.04±0.33⊿ ⊿ ⊿
SLAC-TPC
SLAC-SLD
SLAC-SLD_c
SLAC-SLD_b
NLO
0.1 1)(7.94),(8.1072 NLOLOFFs Z
Z
Expe
rimen
t
Theo
ry
Hadron Production in e+ e- collision
EX. h =
EX. Results of the analysis of NLO pion FF with Kretzer parameterization
up → π + gluon → π +
Fragmentation Functions
3. Effects of the errors of FFs on pPDF analysis
( AExp – AThe ) / σA_FF @ NLO (σA_FF : From Pion FF )
・ Comparison of σA_FF with experimental errors (bar) and pPDF induced errors (band)
: Error from pPDF fit
pPDF: Fixed・ The effect of FF on @ NLOSIDIS2
FFs2
K+
1.02 SIDIS
12 FFFFs2
π+ 2.02 SIDIS
π+
K+
4. Summary
・ The effect of the error of FF on pPDF analysis was studied in several ways, based on my current results of pPDF and FF analyses.
・ The effect tuned out to be small.
・ Rather strong dependence on the choice of FF models
・ Semi-Inclusive DIS, which needs information on FF, is an important process to obtain information on flavor decomposition.
・ pPDF and FF analyses are in progress in pQCD numerical calc. framework.SIDIS Analysis at NLOStatistical error on Kretzer-type FF
Future Subjects:
D. de Florian et al. (DNS05): Phys. Rev. D71, (2005) 094018
Investigation of new models of FF and its validity
278.0
・ Current chi-squared values of pPDF fit
3. Effects of the errors of FFs on pPDF analysispPDF: Fixed
)()(),( 12 hhh
FFsh DADD
)(2 DFFs
)(1 DA p
12
001.0187.0)5.2,09.0( 221 GeVQxA p
proton target
σA_FF = Few % @ LO
Almost the same effect even @ NLO
h = π+
・ Estimation of σA_FF : A1h error from FFs
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