Nucleon Spin Structure Functions in the Resonance Region and the Duality**The project supported by National Natural Science Foundation of China under Grant No. 10075056, and by Foundations of the Chinese Academy of Sciences (X-37), of the Chinese Ministry of Education (B-22), and of the Institute of Theoretical Physics. Thanks also go to CAS Knowledge Innovation Project No. KC2-SW-N02

Abstract

We discuss the nucleon spin structure function g1 and the difference between the proton and neutron targets , based on quark model calculation. Quark-hadron duality for the nucleon spin structure function is also analyzed. Effects of the Δ(1232) and Roper P11(1440) resonances on the spin structure function and on the difference are mentioned. The results of different models for the Roper resonance are also addressed.