The Spin Structure Of Baryon With Five Quark Components

Although some lower energy quark models take significant successes in explaining the properties of the nucleon,there exist a lot of question to be solved,such as the order of the lowest positive and negative parity states in the nucleon,the surprisingly large asymmetry between the(?) and(?) sea quark distributions in the proton in deep inelastic scattering and Drell-Yan experiments,the strangeness in the nucleon,etc.Some recent experiments on parity violation in electron-proton scattering indicate that the strange magnetic moment of the proton and the strange radius are positive.These experimental results imply that the proton may contain five quark components(qqqq_i(?)_i).Previous works on the strange magnetic moments and the lowest negative parity nucleon excited state N~*(1535) suggest that the qqqq_i(?)_i components are in colored quark cluster configuration rather than in baryon-meson configuration.We further investigate the contributions of the qqqq_i(?)_i components to the spin structure of baryons,including magnetic moments,spin content,weak decay constants and spin polarized distribution in deep inelastic scattering.In present work,we take into account the lowest energy qqqq_i(?)_i components with the lowest energy,and assume that the qqqq_i(?)_i components are colored quark cluster configuration.The obtained results are in agree with experimental datal;In particular,the contributions of the down and strange quarks to the proton spin and the sum rule for polarized neutron are negative,in agreement with recent experiments.We also discuss the dependence of the numerical results on the several parameter,and find that our value is not sensitive the oscillator parameter in five quark spatial wave function.These suggest that the conventional 3-quarks model is not a good approximate.Our theoretical analysis for baryon spin structure show that there are about 20 percent five-quark components in proton.This improve our understanding about the baryon structure.The further work need to extend the present model to investigate other properties of baryons.