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

Jun 2-6, 2013, Huangshan, Anhui, China 5

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)

Jun 2-6, 2013, Huangshan, Anhui, China 6

For valence quark

Jun 2-6, 2013, Huangshan, Anhui, China 7

For sea quark

Jun 2-6, 2013, Huangshan, Anhui, China 8

For gluon

Jun 2-6, 2013, Huangshan, Anhui, China 9

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.

Jun 2-6, 2013, Huangshan, Anhui, China 11

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.

Jun 2-6, 2013, Huangshan, Anhui, China 13

Jun 2-6, 2013, Huangshan, Anhui, China 14

Jun 2-6, 2013, Huangshan, Anhui, China 15

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.

Jun 2-6, 2013, Huangshan, Anhui, China 16

Add 2 free parameters for nuclear media effect.

Fermi motion is considered.

Shadowing

enhancement

Nucleon swelling

Jun 2-6, 2013, Huangshan, Anhui, China 17

Jun 2-6, 2013, Huangshan, Anhui, China 18

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.

Jun 2-6, 2013, Huangshan, Anhui, China 25

Jun 2-6, 2013, Huangshan, Anhui, China 26

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

Jun 2-6, 2013, Huangshan, Anhui, China 27

Typical JIMWLK

saturation

Jun 2-6, 2013, Huangshan, Anhui, China 28

GLR-MQ-ZSR

saturation

Jun 2-6, 2013, Huangshan, Anhui, China 29

JIMWLK saturation

Jun 2-6, 2013, Huangshan, Anhui, China 30

GLR-MQ-ZSR

saturation

Jun 2-6, 2013, Huangshan, Anhui, China 31

Jun 2-6, 2013, Huangshan, Anhui, China 32

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