Proton Spin Structure Functions and Quark--Hadron Duality

Quark--hadron duality of three proton spin structure functions g₁, g₂ and g_T are discussed simultaneously. It is found that the onsets of the quark--hadron dualities of g₁^p, g₂^p and g_T^p are similar and they are expected to be at about Q² ～ 2GeV². In addition, our results show that the elastic peak remarkably breaks local quark--hadron duality.