arXiv subjects

Zhi-Gang Wang

Publications and source records attributed to Zhi-Gang Wang.

At least 199 records · Page 11Linked to original sources

arXiv2016

Tetraquark state candidates: $Y(4260)$, $Y(4360)$, $Y(4660)$ and $Z_c(4020/4025)$

In this article, we construct the axialvector-diquark-axialvector-antidiquark type tensor current to interpolate both the vector and axialvector tetraquark states, then calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and obtain the QCD sum rules for both the vector and axialvector tetraquark states. The numerical results support assigning the $Z_c(4020/4025)$ to be the $J^{PC}=1^{+-}$ diquark-antidiquark type tetraquark state, and assigning the $Y(4660)$ to be the $J^{PC}=1^{--}$ diquark-antidiquark type tetraquark state. Furthermore, we take the $Y(4260)$ and $Y(4360)$ as the mixed charmonium-tetraquark states, and construct the two-quark-tetraquark type tensor currents to study the masses and pole residues. The numerical results support assigning the $Y(4260)$ and $Y(4360)$ to be the mixed charmonium-tetraquark states.

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arXiv2016

Analysis of the strong decay $X(5568) \to B_s^0π^+$ with QCD sum rules

In this article, we take the $X(5568)$ to be the scalar diquark-antidiquark type tetraquark state, study the hadronic coupling constant $g_{XB_sπ}$ with the three-point QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension-6 and including both the connected and disconnected Feynman diagrams, then calculate the partial decay width of the strong decay $ X(5568) \to B_s^0 π^+$ and obtain the value $Γ_X=\left(20.5\pm8.1\right)\,\rm{MeV}$, which is consistent with the experimental data $Γ_X = \left(21.9 \pm 6.4 {}^{+5.0}_{-2.5}\right)\,\rm{MeV}$ from the D0 collaboration.

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arXiv2016

Comment on "Hybridized Tetraquarks"

In this comment, I illustrate that the formula $Γ=A\sqrtδ$ suggested in arXiv:1603.07667 comes from a kinematical factor, and has no relation to the existence or non-existence of the $X(5568)$.

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arXiv2016

Analysis of the ${\frac{1}{2}}^{\pm}$ pentaquark states in the diquark-diquark-antiquark model with QCD sum rules

In this article, we construct both the axialvector-diquark-axialvector-diquark-antiquark type and axialvector-diquark-scalar-diquark-antiquark type interpolating currents, then calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and study the masses and pole residues of the $J^P={\frac{1}{2}}^\pm$ hidden-charm pentaquark states with the QCD sum rules in a systematic way. In calculations, we use the formula $μ=\sqrt{M^2_{P}-(2{\mathbb{M}}_c)^2}$ to determine the energy scales of the QCD spectral densities. We take into account the $SU(3)$ breaking effects of the light quarks, and obtain the masses of the hidden charm pentaquark states with the strangeness $S=0,\,-1,\,-2,\,-3$, which can be confronted with the experimental data in the future.

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arXiv2016

Analysis of the ${\frac{1}{2}}^{\pm}$ pentaquark states in the diquark model with QCD sum rules

In this article, we present the scalar-diquark-scalar-diquark-antiquark type and scalar-diquark-axialvector-diquark-antiquark type pentaquark configurations in the diquark model, and study the masses and pole residues of the $J^P={\frac{1}{2}}^\pm$ hidden-charmed pentaquark states in details with the QCD sum rules by extending our previous work on the $J^P={\frac{3}{2}}^-$ and ${\frac{5}{2}}^{+}$ hidden-charmed pentaquark states. We calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion by constructing both the scalar-diquark-scalar-diquark-antiquark type and scalar-diquark-axialvector-diquark-antiquark type interpolating currents. The present predictions of the masses can be confronted to the LHCb experimental data in the future.

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arXiv2016

Analysis of the $P_c(4380)$ and $P_c(4450)$ as pentaquark states in the diquark model with QCD sum rules

In this article, we construct the diquark-diquark-antiquark type interpolating currents, and study the masses and pole residues of the $J^P={\frac{3}{2}}^-$ and ${\frac{5}{2}}^+$ hidden-charmed pentaquark states in details with the QCD sum rules by calculating the contributions of the vacuum condensates up to dimension-10 in the operator product expansion. In calculations, we use the formula $μ=\sqrt{M^2_{P_c}-(2{\mathbb{M}}_c)^2}$ to determine the energy scales of the QCD spectral densities. The present predictions favor assigning the $P_c(4380)$ and $P_c(4450)$ to be the ${\frac{3}{2}}^-$ and ${\frac{5}{2}}^+$ pentaquark states, respectively.

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arXiv2015

Analysis of the heavy mesons in the nuclear matter with the QCD sum rules

In this article, I calculate the contributions of the nuclear matter induced condensates up to dimension 5, take into account the next-to-leading order contributions of the nuclear matter induced quark condensate, study the properties of the scalar, pseudoscalar, vector and axial-vector heavy mesons in the nuclear matter with the QCD sum rules in a systematic way, and obtain the shifts of the masses and decay constants. Furthermore, I study the heavy-meson-nucleon scattering lengths as a byproduct, and obtain the conclusion qualitatively about the possible existence of heavy-meson-nucleon bound states.

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arXiv2015

Analysis of the $Z_c(4200)$ as axial-vector molecule-like state

In this article, we assume the $Z_c(4200)$ as the color octet-octet type axial-vector molecule-like state, and construct the color octet-octet type axial-vector current to study its mass and width with the QCD sum rules. The numerical values $M_{Z_c(4200)}=4.19 \pm 0.08\,\rm{GeV}$ and $Γ_{Z_c(4200)}\approx 334\,\rm{MeV}$ are consistent with the experimental data $M_{Z_c(4200)} = 4196^{+31}_{-29}{}^{+17}_{-13} \,\rm{MeV}$ and $Γ_{Z_c(4200)} = 370^{+70}_{-70}{}^{+70}_{-132}\,\rm{MeV}$, and support assigning the $Z_c(4200)$ to be the color octet-octet type molecule-like state with $J^{PC}=1^{+-}$. Furthermore, we discuss the possible assignments of the $Z_c(3900)$, $Z_c(4200)$ and $Z(4430)$ as the diquark-antidiquark type tetraquark states with $J^{PC}=1^{+-}$.

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arXiv2015

Analysis of the heavy tensor meson's strong decay with QCD sum rules

In this article, the tensor-vector-pseudoscalar type of vertex is analyzed with the QCD sum rules and the local-QCD sum rules. Correspondingly, the hadronic coupling constants of D2*(2460), Ds2*(2573), B2*(5747) and Bs2*(5840), and their decay widths are calculated. The results indicate that the QCD sum rules and the local-QCD sum rules give the consistent descriptions. Finally, the full widths of these 4 tensor mesons are discussed in detail.

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arXiv2015

Analysis of the $Λ_c(2625)$ and $Ξ_c(2815)$ with QCD sum rules

In this article, we study the charmed baryon states $Λ_c(2625)$ and $Ξ_c(2815)$ with the spin-parity ${3\over 2}^-$ by subtracting the contributions from the corresponding charmed baryon states with the spin-parity ${3\over 2}^+$ using the QCD sum rules, and suggest a formula $ μ=\sqrt{M_{Λ_c/Ξ_c}^2-{\mathbb{M}}_c^2}$ with the effective mass ${\mathbb{M}}_c=1.8\,\rm{GeV}$ to determine the energy scales of the QCD spectral densities, and make reasonable predictions for the masses and pole residues. The numerical results indicate that the $Λ_c(2625)$ and $Ξ_c(2815)$ have at least two remarkable under-structures.

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arXiv2015

Semi-leptonic $B\to S$ decays in the standard model and in the universal extra dimension model

In this article, we assume the two nonets of scalar mesons below and above 1 GeV are all $\bar{q}q$ states, and study the semi-leptonic decays $B\to S\ell^-\barν_{\ell}$, $B\to S\ell^+\ell^-$ and $B\to S\barνν$ both in the standard model and in the universal extra dimension model using the $B-S$ form-factors calculated by the light-cone QCD sum rules in our previous work. We obtain the partial decay widths and decay widths, which can be confronted with the experimental data in the future to examine the natures of the scalar mesons and constrain the basic parameter in the universal extra dimension model, the compactification scale $1/R$.

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arXiv2015

Systematic analysis of the $D_{J}(2580)$, $D_{J}^{}(2650)$, $D_{J}(2740)$, $D_{J}^{}(2760)$, $D_{J}(3000)$ and $D_{J}^{*}(3000)$ in $D$ meson family

In this work, we tentatively assign the charmed mesons $D_{J}(2580)$, $D_{J}^{*}(2650)$, $D_{J}(2740)$, $D_{J}^{*}(2760)$, $D_{J}(3000)$ and $D_{J}^{*}(3000)$ observed by the LHCb collaboration according to their spin-parity and masses, then study their strong decays to the ground state charmed mesons plus light pseudoscalar mesons with the $^{3}P_{0}$ model. According to these study, we assigned the $D_{J}^{*}(2760)$ as the $1D\frac{5}{2}3^{-}$ state, the $D_{J}^{*}(3000)$ as the $1F\frac{5}{2}2^{+}$ or $1F\frac{7}{2}4^{+}$ state, the $D_{J}(3000)$ as the $1F\frac{7}{2}3^{+}$ or $2P\frac{1}{2}1^{+}$ state in the $D$ meson family. As a byproduct, we also study the strong decays of $2P\frac{1}{2}0^{+}$,$2P\frac{3}{2}2^{+}$, $3S\frac{1}{2}1^{-}$, $3S\frac{1}{2}0^{-}$ etc, states, which will be helpful to further experimentally study mixings of these $D$ mesons.

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arXiv2015

Tetraquark state candidates: $Y(4140)$, $Y(4274)$ and $X(4350)$

In this article, we tentatively assign the $Y(4140)$, $Y(4274)$ and $X(4350)$ to be the scalar and tensor $cs\bar{c}\bar{s}$ tetraquark states, respectively, and study them with the QCD sum rules. In the operator product expansion, we take into account the vacuum condensates up to dimension-10. In calculations, we use the formula $μ=\sqrt{M^2_{X/Y/Z}-(2{\mathbb{M}}_c)^2}$ to determine the energy scales of the QCD spectral densities. The numerical results favor assigning the $Y(4140)$ to be the $J^{PC}=2^{++}$ diquark-antidiquark type tetraquark state, and disfavor assigning the $Y(4274)$ and $X(4350)$ to be the $0^{++}$ or $2^{++}$ tetraquark states.

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arXiv2015

$B-S$ transition form-factors with the light-cone QCD sum rules

In the article, we assume the two scalar nonet mesons below and above 1 GeV are all $\bar{q}q$ states, in case I, the scalar mesons below 1 GeV are the ground states, in case II, the scalar mesons above 1 GeV are the ground states. We calculate the $B-S$ form-factors by taking into account the perturbative ${\mathcal{O}}(α_s)$ corrections to the twist-2 terms using the light-cone QCD sum rules and fit the numerical values of the form-factors into the single-pole forms, which have many phenomenological applications.

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arXiv2015

The lowest hidden charmed tetraquark state from QCD sum rules

In this article, we study the $S\bar{S}$ type scalar tetraquark state $cq\bar{c}\bar{q}$ in details with the QCD sum rules by calculating the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and obtain the value $M_{Z_c}=\left(3.82^{+0.08}_{-0.08}\right)\,\rm{GeV}$, which is the lowest mass for the hidden charmed tetraquark states from the QCD sum rules. Furthermore, we calculate the hadronic coupling constants $G_{Z_cη_cπ}$ and $G_{Z_cDD}$ with the three-point QCD sum rules, then study the strong decays $ Z_c\to η_cπ\, ,\, DD$, and observe that the total width $Γ_{Z_c}\approx 21\,\rm{MeV}$. The present predictions can be confronted with the experimental data in the futures at the BESIII, LHCb and Belle-II.

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arXiv2014

Reanalysis of the $Z_c(4020)$, $Z_c(4025)$, $Z(4050)$ and $Z(4250)$ as tetraquark states with QCD sum rules

In this article, we calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and study the $Cγ_μ-Cγ_ν$ type scalar, axial-vector and tensor tetraquark states in details with the QCD sum rules. In calculations, we use the formula $μ=\sqrt{M^2_{X/Y/Z}-(2{\mathbb{M}}_c)^2}$ to determine the energy scales of the QCD spectral densities. The predictions $M_{J=2} =\left(4.02^{+0.09}_{-0.09}\right)\,\rm{GeV}$, $M_{J=1} =\left(4.02^{+0.07}_{-0.08}\right)\,\rm{GeV}$ favor assigning the $Z_c(4020)$ and $Z_c(4025)$ as the $J^{PC}=1^{+-}$ or $2^{++}$ diquark-antidiquark type tetraquark states, while the prediction $M_{J=0}=\left(3.85^{+0.15}_{-0.09}\right)\,\rm{GeV}$ disfavors assigning the $Z(4050)$ and $Z(4250)$ as the $J^{PC}=0^{++}$ diquark-antidiquark type tetraquark states. Furthermore, we discuss the strong decays of the $0^{++}$, $1^{+-}$, $2^{++}$ diquark-antidiquark type tetraquark states in details.

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arXiv2014

Analysis of the $Z(4430)$ as the first radial excitation of the $Z_c(3900)$

In this article, we take the $Z_c(3900)$ and $Z(4430)$ as the ground state and the first radial excited state of the axial-vector tetraquark states with $J^{PC}=1^{+-}$, respectively, and study their masses and pole residues with the QCD sum rules by calculating the contributions of the vacuum condensates up to dimension-10 in a consistent way in the operator product expansion. The numerical result favors assigning the $Z_c(3900)$ and $Z(4430)$ as the ground state and first radial excited state of the axial-vector tetraquark states, respectively.

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arXiv2014

$D_{s3}^(2860)$ and $D_{s1}^(2860)$ as the 1D $c\bar{s}$ states

In this article, we take the $D_{s3}^*(2860)$ and $D_{s1}^*(2860)$ as the $1^3{\rm D}_3$ and $1^3{\rm D}_1$ $c\bar{s}$ states, respectively, study their strong decays with the heavy meson effective theory by including the chiral symmetry breaking corrections. We can reproduce the experimental data ${\rm Br}\left(D_{sJ}^*(2860)\to D^*K\right)/{\rm Br}\left(D_{sJ}^*(2860)\to D K\right) =1.10 \pm 0.15 \pm 0.19$ with suitable hadronic coupling constants, the assignment of the $D_{sJ}^*(2860)$ as the $D_{s3}^*(2860)$ is favored, the chiral symmetry breaking corrections are large. Furthermore, we obtain the analytical expressions of the decay widths, which can be confronted with the experimental data in the future to fit the unknown coupling constants. The predictions of the ratios among the decay widths can be used to study the decay properties of the $D_{s3}^*(2860)$ and $D_{s1}^*(2860)$ so as to identify them unambiguously. On the other hand, if the chiral symmetry breaking corrections are small, the large ratio $R=1.10 \pm 0.15 \pm 0.19$ requires that the $D_{sJ}^*(2860)$ consists of at least four resonances $D_{s1}^*(2860)$, $D_{s2}^*(2860)$, $D_{s2}^{*\prime}(2860)$, $D_{s3}^*(2860)$.

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