The color number Nc-dependence of the interplay between quark-antiquark condensates （q^-q） and diquark condensates （qq） in vacuum in two-flavor four-fermion interaction models is researched. The results show that ...The color number Nc-dependence of the interplay between quark-antiquark condensates （q^-q） and diquark condensates （qq） in vacuum in two-flavor four-fermion interaction models is researched. The results show that the Gs-Hs （the coupling constant of scalar （q^-q）2-scalar （qq）2 channel） phase diagrams will be qualitatively consistent with the case of Nc = 3 as Nc varies in 4D Nambu-Jona-Lasinio model and 219 Gross Neveu （GN） model, However, in 3D GN model, the behavior of the Gs-Hp （the coupling constant of pseudoscalar （qq）^2 channel） phase diagram will obviously depend on No. The known characteristic that a 3D GN model does not have the coexistence phase of the condensates （q^-q） and （qq） is proven to appear only in the case of Nc ≤ 4. In all the models, the regions occupied by the phases containing the diquark condensates （qq） in corresponding phase diagrams will gradually decrease as Nc grows up and finally go to zero if Nc → ∞, i.e. in this limit only the pure （q^-q） phase could exist.展开更多
In this article, we calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and study the C γμ- Cγνtype scalar, axial-vector and tensor tetraquark states in deta...In this article, we calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and study the C γμ- Cγνtype scalar, axial-vector and tensor tetraquark states in details with the QCD sum rules. In calculations, we use the formula μ = √M^2X/ Y /Z-（2Mc）^2 to determine the energy scales of the QCD spectral densities. The predictions MJ =2=（4.02-0.09^＋0.09） GeV, MJ =1=（4.02-0.08^＋0.07） GeV favor assigning the Zc（4020） and Zc（4025） as the J^PC= 1^＋-or 2^＋＋diquark-antidiquark type tetraquark states, while the prediction MJ =0=（3.85-0.09^＋0.15） GeV disfavors assigning the Z（4050） and Z（4250） as the J^P C= 0^＋＋ diquark-antidiquark type tetraquark states. Furthermore, we discuss the strong decays of the 0^＋＋, 1^＋-, 2^＋＋diquark-antidiquark type tetraquark states in details.展开更多
In this article, we take the X(5568) as the diquark-antidiquark type tetraquark state with the spin-parity J^P= 0^+, construct the scalar-diquark-scalar-antidiquark type current, carry out the operator product expansi...In this article, we take the X(5568) as the diquark-antidiquark type tetraquark state with the spin-parity J^P= 0^+, construct the scalar-diquark-scalar-antidiquark type current, carry out the operator product expansion up to the vacuum condensates of dimension-10, and study the mass and pole residue in details with the QCD sum rules. We obtain the value M_X =(5.57 ± 0.12) Ge V, which is consistent with the experimental data. The present prediction favors assigning the X(5568) to be the scalar tetraquark state.展开更多
基金National Natural Science Foundation of China(10975033,11275048,11365002)Guangxi Province Natural Science Foundation(2013GXNSFBB053007,2011GXNSGA018140)+1 种基金Department of Guangxi Education for the Excellent Scholars of Higher Education(2011-54)Doctoral Science Foundation of Guangxi University of Science and Technology(11Z16)~~
基金supported by the National Natural Science Foundation of China under Grant No. 10475113
文摘The color number Nc-dependence of the interplay between quark-antiquark condensates （q^-q） and diquark condensates （qq） in vacuum in two-flavor four-fermion interaction models is researched. The results show that the Gs-Hs （the coupling constant of scalar （q^-q）2-scalar （qq）2 channel） phase diagrams will be qualitatively consistent with the case of Nc = 3 as Nc varies in 4D Nambu-Jona-Lasinio model and 219 Gross Neveu （GN） model, However, in 3D GN model, the behavior of the Gs-Hp （the coupling constant of pseudoscalar （qq）^2 channel） phase diagram will obviously depend on No. The known characteristic that a 3D GN model does not have the coexistence phase of the condensates （q^-q） and （qq） is proven to appear only in the case of Nc ≤ 4. In all the models, the regions occupied by the phases containing the diquark condensates （qq） in corresponding phase diagrams will gradually decrease as Nc grows up and finally go to zero if Nc → ∞, i.e. in this limit only the pure （q^-q） phase could exist.
基金Supported by National Natural Science Foundation of China under Grant No.11375063Natural Science Foundation of Hebei Province under Grant No.A2014502017
文摘In this article, we calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and study the C γμ- Cγνtype scalar, axial-vector and tensor tetraquark states in details with the QCD sum rules. In calculations, we use the formula μ = √M^2X/ Y /Z-（2Mc）^2 to determine the energy scales of the QCD spectral densities. The predictions MJ =2=（4.02-0.09^＋0.09） GeV, MJ =1=（4.02-0.08^＋0.07） GeV favor assigning the Zc（4020） and Zc（4025） as the J^PC= 1^＋-or 2^＋＋diquark-antidiquark type tetraquark states, while the prediction MJ =0=（3.85-0.09^＋0.15） GeV disfavors assigning the Z（4050） and Z（4250） as the J^P C= 0^＋＋ diquark-antidiquark type tetraquark states. Furthermore, we discuss the strong decays of the 0^＋＋, 1^＋-, 2^＋＋diquark-antidiquark type tetraquark states in details.
基金Supported by National Natural Science Foundation under Grant No.11375063Natural Science Foundation of Hebei Province under Grant No.A2014502017
文摘In this article, we take the X(5568) as the diquark-antidiquark type tetraquark state with the spin-parity J^P= 0^+, construct the scalar-diquark-scalar-antidiquark type current, carry out the operator product expansion up to the vacuum condensates of dimension-10, and study the mass and pole residue in details with the QCD sum rules. We obtain the value M_X =(5.57 ± 0.12) Ge V, which is consistent with the experimental data. The present prediction favors assigning the X(5568) to be the scalar tetraquark state.
