Study of quark-hadron duality in a constitue

nt quark model

by Dong Yu-Bing(董宇兵）

Institute of High Energy Physics (IHEP)P. R. China

MENU2004(Aug.30—Sept.4, Beijing)

Outline

I), Motivations, new data, Duality.

II), Constituent quark model and resonance contribution.

III), Discussions and summary.

I), Motivations Structures of Nucleon and low-lying resonances (Δ

(1232), Roper N(1440)*) Transitions properties, Strong decays

Nucleon spin, spin-dependent structure function (GDH)

Duality (Connection between the observable in the resonance region and in the DIS region)

New data and findings:

a), Pentaquark (M=1540MeV, Narrow width)

b), New resonances: X(3872) ,

c), Enhancement in by BEPC(2003)

d), Duality for the structure functions

)2317(*SJD

ppJ /

2F

New Challenges

1), All those new data have called for accuracy of the model calculations.

2), Some of the data are in disagreement with the quark potential models.

3), Pentaquark opens a new window.

4), Duality of great interests.

Quark-hadron duality

Strong interaction: Two end points

1), nQCD, Confinements : Resonance bumps

2), pQCD, Asymptotic freedom

3), Connection of pQCD and nQCD.

Duality(BG) for the structure functions Observable can be explained by two different kinds of Languages (R, S)

Bloom-Gilman Duality( ,1970).

Resonance region data oscillate around the scaling curve.

smooth scaling curves seen at high Q**2 was an accurate average over the resonance bumps at a low Q**2. (4GeV**2)

2F

Rujula, Georgi and Politzer The resonance strengths average to a global scaling

curve resembling the curve of DIS, as the higher-twist effect is not large, if averaged over a large kinematics region.

New data of JLab. By I. Niculescu et al. Phys. Rev. Lett. 85, 1182, 1186 (2000),

II), Constituent quark model and resonance contribution

Quark model calculation for the structure function(Phys. Lett. B408, Y. B. Dong) Donnnachie and Landshoff(84) F2 structure function:NMC(95) ,Gluek,Reya,Vogt(98)

For g1 spin structure function: HEARMS SLAC-E143(95),GOTO(AAC, 00), Gluek, Reya et al(98)

Further study of duality for Parametrization form of by Simula (PRD64)

1g

1g

1), Duality is seen from our model calculations.

2), Delta resonance (g1) violates the duality.

3), Duality in the elastic region is not clearly seen.

4), Local duality in the second resonance region is expected.

5), Duality of g1 is expected at .

III), Discussions and summary

22 2GeVQ

Summary

1), Duality-connection2), High twist,3), Information,4), Quark model5), Data, and BG (!!!!)