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A QCD evolution equation and

EIC@HIAF

ZHU WEI ECNU

2013.7. WeiHai

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• Parton distributions in proton and nuclei is an important knowledge for EIC

EIC@HIAF vs BEPC

QCD evolution equation is a necessary tool for understanding parton distributions

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Kinematic domainEIC@HIAF

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QCD evolution equations

• DGLAP x>10^{-3}, Q^2>1-4 GeV^2

• GLRMQ x<10^{-2}?

• BFKL x<10^{-4}?

• BK x<10^{-4}?

• JIMWLK x<10^{-4}, Q^2>1 GeV^2

• ZRS x>10^{-4}, Q^2>0.06 GeV^2

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Gribov, Levin and Ryskin , Mueller and Qiu

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W.Zhu, D.L.Xue, K.M. Chai, Z.X. Xu, Phys. Lett. B317 (1993) 200

W.Zhu, K.M.Chai, B.He, Nucl. Phys. B427 (1994) 525

W.Zhu, K.M.Chai, B.He, Nucl. Phys. B449 (1995) 183

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Zhu-Shen-Ruan

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Complete version of equation

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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, Nuclear Physics B 692 (2004) 417.

L.V. Gribov, E.M. Levin and M.G. Ryskin, Phys. Rep. 100, 1 (1983).

A.H. Mueller and J. Qiu, Nucl. Phys. B268, 427 (1986)

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1. First realize three valence quark input

• G. Parisi and R. Petronzio, Phys. Lett. 62B, 331 (1976)

• V.A. Novikov, M.A. Shifman, A.I. Vainshtein, V.I. Zakharov:JETP Len. 24 (1976) 341

• M. Gluck, E. Reya: Nucl. Phys. B130, 76 (1977)

Unsuccessful

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Input distributions

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Why equation can work at Q^2<<1 GeV^2?

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A bridge connecting withChiral quark model

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2. Minimum free parameters

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Typical database of PDF

• Proton GRV 23 parameters+DGLAP

• CTEQ 36parameters+DGLAP

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Proton 4 free parameters

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3. EMC effectAdd 2 free parameters

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4. Nuclear PDF

• HKM 16 free parameters

• EPS 24 free parameters

• Our 2 free parameters

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5. Quark saturation

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Quark saturation has similar properties as JIMWLK saturation

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JIMWLK saturation (gluon)

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6. Nuclear shadowing saturation

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Next step in EIC@HIAF

• PDF database for proton

• nPDF database for nuclei

• Spin-dependent PDF

• PDF for pion and kaon

• SRC

• Antishadowing

• TMD…….