We discuss the nucleon spin structure function g<SUB>1</SUB> and the difference between the proton and neutron targets , based on quark model calculation. Quark-hadron duality for the nucleon spin structur...We discuss the nucleon spin structure function g<SUB>1</SUB> 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 P<SUB>11</SUB>(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.展开更多
The structure and decay properties of d＊ have been detailedly investigated in both the chiral SU（3） quark model and the extended chiral SU（3） quark model that describe the energies of baryon ground states and the...The structure and decay properties of d＊ have been detailedly investigated in both the chiral SU（3） quark model and the extended chiral SU（3） quark model that describe the energies of baryon ground states and the nucleon-nucleon （NN） scattering data satisfactorily. By performing a dynamical coupled-channels study of the system of △△ and hidden-color channel （CC） with quantum numbers l（JP） = 0（3^＋） in the framework of the resonating group method （RGM）, we find that the d＊ has a mass of about 2.38-2.42 GeV and a root-mean-square radius （RMS） of about 0.76-0.88 fm. The channel wave function is extracted by a projection of the RGM wave function onto the physical basis, and the fraction of CC component in the d＊ is found to be about 66%-68%, which indicates that the d＊ is a hexaquark-dominated exotic state. Based on this scenario the partial decay widths of d＊ → dπ^0π^0 and d＊ → dn^＋n^- are further explicitly evaluated and the total width is then obtained by use of the branching ratios extracted from the measured cross sections of other possible decay channels. Both the mass and the decay width of d＊ calculated in this work are compatible with the data （M ≈ 2380 MeV, F ≈ 70 MeV） reported by WASA-at-COSY Collaboration.展开更多
文摘We discuss the nucleon spin structure function g<SUB>1</SUB> 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 P<SUB>11</SUB>(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.
基金the National Natural Science Foundation of China(Grant Nos.1147518111475192+2 种基金11035006 and 11165005)the fund provided to the Sino-German CRC 110"Symmetries and the Emergence of Structure in QCD"project by the DFGthe IHEP InnovationFund(Grant No.Y4545190Y2)
文摘The structure and decay properties of d＊ have been detailedly investigated in both the chiral SU（3） quark model and the extended chiral SU（3） quark model that describe the energies of baryon ground states and the nucleon-nucleon （NN） scattering data satisfactorily. By performing a dynamical coupled-channels study of the system of △△ and hidden-color channel （CC） with quantum numbers l（JP） = 0（3^＋） in the framework of the resonating group method （RGM）, we find that the d＊ has a mass of about 2.38-2.42 GeV and a root-mean-square radius （RMS） of about 0.76-0.88 fm. The channel wave function is extracted by a projection of the RGM wave function onto the physical basis, and the fraction of CC component in the d＊ is found to be about 66%-68%, which indicates that the d＊ is a hexaquark-dominated exotic state. Based on this scenario the partial decay widths of d＊ → dπ^0π^0 and d＊ → dn^＋n^- are further explicitly evaluated and the total width is then obtained by use of the branching ratios extracted from the measured cross sections of other possible decay channels. Both the mass and the decay width of d＊ calculated in this work are compatible with the data （M ≈ 2380 MeV, F ≈ 70 MeV） reported by WASA-at-COSY Collaboration.
