Xurong Chen, Jianhong Ruan, Rong Wang,
Pengming Zhang and Wei Zhu*
Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS)
Department of Physics, East China Normal University (ECNU)
The Fifth Workshop on Hadron Physics in China and Opportunities in US, 2013
Jun 2-6, 2013, Huangshan, Anhui, China 2
Parton distributions and QCD evolution
equations;
A new approach to parton distributions in the
proton and nuclei;
Quark saturation in low Q2 range.
Jun 2-6, 2013, Huangshan, Anhui, China 3
Quark and gluon distributions are important
knowledge of nucleon and nuclei.
Worldwide proposing EIC will complete our
knowledge of sea quark, gluon and nuclear
media modification.
MEIC, eRHIC, EIC@HIAF...
Jun 2-6, 2013, Huangshan, Anhui, China 4
“QCD is successful and we believe QCD”
DGLAP x > 10-3, Q2 > 1 ~ 4 GeV2
GLR-MQ x <~ 10-2
BFKL x <~ 10-4
BK x <~ 10-4
JIMWLK x <~ 10-4, Q2 > 1 GeV2
ZSR x > 10-4, Q2 > 0.06 GeV2
QC
D e
volu
tio
n e
qu
ati
on
s
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GLR-MQ-ZSR: DGLAP + Leading high twist
corrections
W. Zhu, Nucl. Phys. B551, 245 (1999);
W. Zhu and J.H.Ruan, Nucl. Phys. B559, 378 (1999);
W. Zhu, Z.Q. Shen and J.H. Ruan, Nucl. Phys. B692 ,417.(2004)
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For valence quark
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For sea quark
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For gluon
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Proton(global analysis)
GRV 23 parameters+DGLAP
CTEQ 36 parameters+DGLAP
nuclei HKM +16 parameters
EPS +24 parameters
A large uncretainty (>100%) in nuclear gluon density. We need to pin it down.
Jun 2-6, 2013, Huangshan, Anhui, China 10
GLR-MQ-ZSR + natural input
We have only 4 free parameters to give PDF
predictions.
And first realize three valence quark input as
the non-perturbative input.
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Natural input:
μ2 = 0.064 GeV2
Another free parameter
in GLR-MQ-ZSR equation.
Jun 2-6, 2013, Huangshan, Anhui, China 12
The initial input for GLR-MQ-ZSR evolution.
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GLR-MQ-ZSR offers a bridge to connect quark
models of hadron and various non-perturbative
effects on them with measured structure functions
at high scale Q2.
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Add 2 free parameters for nuclear media effect.
Fermi motion is considered.
Shadowing
enhancement
Nucleon swelling
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Jun 2-6, 2013, Huangshan, Anhui, China 19
Weak short
range
correlation
caused by
fermi
motion.
Jun 2-6, 2013, Huangshan, Anhui, China 20
The gluon is dynamically determined. The uncertainty is small.
Jun 2-6, 2013, Huangshan, Anhui, China 21
Weak Q2 dependence
Jun 2-6, 2013, Huangshan, Anhui, China 22
Add 1 parameter for hadron part in low Q2
range.
Jun 2-6, 2013, Huangshan, Anhui, China 23
Fit good to
experimental
data.
Jun 2-6, 2013, Huangshan, Anhui, China 24
Quark distributions exhibit a flattish form at small x, while
gluon distribution does not.
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GLR-MQ-ZSR saturation,
Qs < 1 GeV, quark saturation.
JIMWLK saturation,
Qs > 1 GeV, gluon saturation.
GLR-MQ-ZRS saturation has similar properties
as JIMWLK saturation
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Typical JIMWLK
saturation
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GLR-MQ-ZSR
saturation
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JIMWLK saturation
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GLR-MQ-ZSR
saturation
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Jun 2-6, 2013, Huangshan, Anhui, China 33
PDF database for proton
nPDF database for nuclei
Spin-dependent PDF
PDF for pion and kaon
SRC
Antishadowing
TMD……
Jun 2-6, 2013, Huangshan, Anhui, China 34