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Zhi-Gang Wang

Publications and source records attributed to Zhi-Gang Wang.

At least 163 records · Page 9Linked to original sources
arXiv2018

Analysis of the mass and width of the $X(4140)$ as axialvector tetraquark state

In this article, we construct both the $[sc]_T[\bar{s}\bar{c}]_A+[sc]_A[\bar{s}\bar{c}]_T$ type and $[sc]_T[\bar{s}\bar{c}]_V-[sc]_V[\bar{s}\bar{c}]_T$ type axialvector currents with $J^{PC}=1^{++}$ to study the mass of the $X(4140)$ with the QCD sum rules. The predicted masses support assigning the $X(4140)$ to be the $[sc]_T[\bar{s}\bar{c}]_V-[sc]_V[\bar{s}\bar{c}]_T$ type axialvector tetraquark state. Then we study the hadronic coupling constant $g_{XJ/ψϕ}$ with the QCD sum rules based on solid quark-hadron duality, and obtain the decay width $Γ(X(4140)\to J/ψϕ)=86.9\pm22.6\,{\rm{MeV}}$, which is in excellent agreement with the experimental data $83\pm 21^{+21}_{-14} {\mbox{ MeV}}$ from the LHCb collaboration.

hep-ph↗
arXiv2018

Analysis of the vector tetraquark states with P-waves between the diquarks and antidiquarks via the QCD sum rules

In this article, we introduce a P-wave between the diquark and antidiquark explicitly to construct the vector tetraquark currents, and study the vector tetraquark states with the QCD sum rules systematically, and obtain the lowest vector tetraquark masses up to now. The present predictions support assigning the $Y(4220/4260)$, $Y(4320/4360)$, $Y(4390)$ and $Z(4250)$ to be the vector tetraquark states with a relative P-wave between the diquark and antidiquark pair.

hep-ph↗
arXiv2018

Scalar tetraquark state candidates: $X(3915)$, $X(4500)$ and $X(4700)$

In this article, we tentatively assign the $X(3915)$ and $X(4500)$ to be the ground state and the first radial excited state of the axialvector-diquark-axialvector-antidiquark type scalar $cs\bar{c}\bar{s}$ tetraquark states, respectively, assign the $X(4700)$ to be the ground state vector-diquark-vector-antidiquark type scalar $cs\bar{c}\bar{s}$ tetraquark state, and study their masses and pole residues with the QCD sum rules in details by calculating the contributions of the vacuum condensates up to dimension 10. The numerical results support assigning the $X(3915)$ and $X(4500)$ to be the ground state and the first radial excited state of the axialvector-diquark-axialvector-antidiquark type scalar $cs\bar{c}\bar{s}$ tetraquark states, respectively, and assigning the $X(4700)$ to be the ground state vector-diquark-vector-antidiquark type scalar $cs\bar{c}\bar{s}$ tetraquark state.

hep-ph↗
arXiv2018

Lowest vector tetraquark states: $Y(4260/4220)$ or $Z_c(4100)$

In this article, we take the $Y(4260/4220)$ as the vector tetraquark state with $J^{PC}=1^{--}$, and construct the $Cγ_5\otimes\stackrel{\leftrightarrow}{\partial}_μ\otimes γ_5C$ type diquark-antidiquark current to study its mass and pole residue with the QCD sum rules in details by taking into account the vacuum condensates up to dimension 10 in a consistent way. The predicted mass $M_{Y}=4.24\pm0.10\,\rm{GeV}$ is in excellent agreement with experimental data and supports assigning the $Y(4260/4220)$ to be the $Cγ_5\otimes\stackrel{\leftrightarrow}{\partial}_μ\otimes γ_5C$ type vector tetraquark state, and disfavors assigning the $Z_c(4100)$ to be the $Cγ_5\otimes\stackrel{\leftrightarrow}{\partial}_μ\otimes γ_5C$ type vector tetraquark state. It is the first time that the QCD sum rules have reproduced the mass of the $Y(4260/4220)$ as a vector tetraquark state.

hep-ph↗
arXiv2018

Analysis of the strong vertices of $Σ_cND^{*}$ and $Σ_bNB^{*}$ in QCD sum rules

The strong coupling constant is an important parameter which can help us to understand the strong decay behaviors of baryons. In our previous work, we have analyzed strong vertices $Σ_{c}^{*}ND$, $Σ_{b}^{*}NB$, $Σ_{c}ND$, $Σ_{b}NB$ in QCD sum rules. Following these work, we further analyze the strong vertices $Σ_{c}ND^{*}$ and $Σ_{b}NB^{*}$ using the three-point QCD sum rules under Dirac structures $q\!\!\!/p\!\!\!/γ_α$ and $q\!\!\!/p\!\!\!/p_α$. In this work, we first calculate strong form factors considering contributions of the perturbative part and the condensate terms $\langle\overline{q}q\rangle$, $\langle\frac{α_{s}}πGG\rangle$ and $\langle\overline{q}g_{s}σGq\rangle$. Then, these form factors are used to fit into analytical functions. According to these functions, we finally determine the values of the strong coupling constants for these two vertices $Σ_{c}ND^{*}$ and $Σ_{b}NB^{*}$.

hep-ph↗
arXiv2018

Analysis of the doubly heavy baryon states and pentaquark states with QCD sum rules

In this article, we study the doubly heavy baryon states and pentaquark states with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension $7$ and $13$ respectively in a consistent way. In calculations, we separate the contributions of the negative parity and positive parity hadron states unambiguously, and study the masses and pole residues of the doubly heavy baryon states and pentaquark states in details. The present predictions can be confronted to the experimental data in the future.

hep-ph↗
arXiv2018

The scalar and pseudoscalar hidden-charm tetraquark states with QCD sum rules

Based on the diquark configuration, we construct the diquark-antidiquark interpolating tetraquark currents with $J^{PC}=1^{-\pm}$ and $1^{+\pm}$, which can couple to the scalar and pseudoscalar tetraquark states respectively, since they are not conserved currents. Then we investigate their two-point correlation functions including the contributions of the vacuum condensates up to dimension-10 and extract the masses and pole residues of the tetraquark states with $J^{PC}=0^{+\pm}$ and $0^{-\pm}$ through the QCD sum rule approach. The predicted masses can be confronted with the experimental data in the future. Moreover, we briefly discuss the possible decay patterns of the tetraquark states.

hep-ph↗
arXiv2018

Possible pentaquark candidates: new excited $Ω_c$ states

In this article, we study the axialvector-diquark-scalar-diquark-antiquark type charmed pentaquark states with $J^P={\frac{3}{2}}^\pm$ with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension $13$ in a consistent way. In calculations, we separate the contributions of the negative parity and positive parity pentaquark states unambiguously, and choose three sets input parameters to study the masses and pole residues of the charmed pentaquark states $uuuc\bar{u}$ and $sssc\bar{s}$ in details. Then we estimate the masses of the charmed pentaquark states $ssuc\bar{u}$, $susc\bar{u}$, $ssdc\bar{d}$ and $sdsc\bar{d}$ with $J^P={\frac{3}{2}}^-$ to be $3.15\pm0.13\,\rm{GeV}$ according to the $SU(3)$ breaking effects, which is compatible with the $Ω_c(3050)$, $Ω_c(3066)$, $Ω_c(3090)$, $Ω_c(3119)$.

hep-ph↗
arXiv2018

Analysis of the scalar, axialvector, vector, tensor doubly charmed tetraquark states with QCD sum rules

In this article, we construct the axialvector-diquark-axialvector-antidiquark type currents to interpolate the scalar, axialvector, vector, tensor doubly charmed tetraquark states, and study them with QCD sum rules systematically by carrying out the operator product expansion up to the vacuum condensates of dimension 10 in a consistent way, the predicted masses can be confronted to the experimental data in the future. We can search for those doubly charmed tetraquark states in the Okubo-Zweig-Iizuka super-allowed strong decays to the charmed meson pairs.

hep-ph↗
arXiv2018

Vector tetraquark state candidates: $Y(4260/4220)$, $Y(4360/4320)$, $Y(4390)$ and $Y(4660/4630)$

In this article, we construct the $C \otimes γ_μC$ and $Cγ_5 \otimes γ_5γ_μC$ type currents to interpolate the vector tetraquark states, then carry out the operator product expansion up to the vacuum condensates of dimension-10 in a consistent way, and obtain four QCD sum rules. In calculations, we use the formula $μ=\sqrt{M^2_{Y}-(2{\mathbb{M}}_c)^2}$ to determine the optimal energy scales of the QCD spectral densities, moreover, we take the experimental values of the masses of the $Y(4260/4220)$, $Y(4360/4320)$, $Y(4390)$ and $Y(4660/4630)$ as input parameters and fit the pole residues to reproduce the correlation functions at the QCD side. The numerical results support assigning the $Y(4660/4630)$ to be the $C \otimes γ_μC$ type vector tetraquark state $c\bar{c}s\bar{s}$, assigning the $Y(4360/4320)$ to be $Cγ_5 \otimes γ_5γ_μC$ type vector tetraquark state $c\bar{c}q\bar{q}$, and disfavor assigning the $Y(4260/4220)$ and $Y(4390)$ to be the pure vector tetraquark states.

hep-ph↗
arXiv2018

On properties of the solutions to the $α$-harmonic equation

The aim of this paper is to establish properties of the solutions to the $α$-harmonic equations: $Δ_α(f(z))=\partial{z}[(1-{|{z}|}^{2})^{-α} \overline{\partial}{z}f](z)=g(z)$, where $g:\overline{\mathbb{ID}}\rightarrow\mathbb{C}$ is a continuous function and $\overline{\mathbb{D}}$ denotes the closure of the unit disc $\mathbb{D}$ in the complex plane $\mathbb{C}$. We obtain Schwarz type and Schwarz-Pick type inequalities for the solutions to the $α$-harmonic equation. In particular, for $g\equiv 0$, the solutions to the above equation are called $α$-harmonic functions. We determine the necessary and sufficient conditions for an analytic function $ψ$ to have the property that $f\circψ$ is $α$-harmonic function for any $α$-harmonic function $f$. Furthermore, we discuss the Bergman-type spaces on $α$-harmonic functions.

math.AP↗
arXiv2018

Analysis of the triply-charmed pentaquark states with QCD sum rules

In this article, we construct the scalar-diquark-scalar-diquark-antiquark type current to study the ground state triply charmed pentaquark states with the QCD sum rules. We separate the contributions of the negative-parity and positive parity triply charmed pentaquark states explicitly, and take the energy scale formula $μ=\sqrt{M^2_{P}-(3{\mathbb{M}}_c)^2}$ to determine the optimal energy scales of the QCD spectral densities. The predicted pentaquark masses can be confronted to the experimental data in the future.

hep-ph↗
arXiv2018

The magnetic moment of the $Z_c(3900)$ as an axialvector tetraquark state with QCD sum rules

In this article, we assign the $Z_c^\pm(3900)$ to be the diquark-antidiquark type axialvector tetraquark state, study its magnetic moment with the QCD sum rules in the external weak electromagnetic field by carrying out the operator product expansion up to the vacuum condensates of dimension 8. We pay special attention to matching the hadron side with the QCD side of the correlation function to obtain solid duality, the routine can be applied to study other electromagnetic properties of the exotic particles.

hep-ph↗
arXiv2018

Scalar hidden-charm tetraquark states with QCD sum rules

In this article, we study the masses and pole residues of the pseudoscalar-diquark-pseudoscalar-antidiquark type and vector-diquark-vector-antidiquark type scalar hidden-charm $cu\bar{c}\bar{d}$ ($cu\bar{c}\bar{s}$) tetraquark states with QCD sum rules by taking into account the contributions of the vacuum condensates up to dimension-10 in the operator product expansion. The predicted masses can be confronted with the experimental data in the future. Possible decays of those tetraquark states are also discussed.

hep-ph↗
arXiv2018

The decay width of the $Z_c(3900)$ as an axialvector tetraquark state in solid quark-hadron duality

In this article, we tentatively assign the $Z_c^\pm(3900)$ to be the diquark-antidiquark type axialvector tetraquark state, study the hadronic coupling constants $G_{Z_cJ/ψπ}$, $G_{Z_cη_cρ}$, $G_{Z_cD \bar{D}^{*}}$ with the QCD sum rules in details. We take into account both the connected and disconnected Feynman diagrams in carrying out the operator product expansion, as the connected Feynman diagrams alone cannot do the work. Special attentions are paid to matching the hadron side of the correlation functions with the QCD side of the correlation functions to obtain solid duality, the routine can be applied to study other hadronic couplings directly. We study the two-body strong decays $Z_c^+(3900)\to J/ψπ^+$, $η_cρ^+$, $D^+ \bar{D}^{*0}$, $\bar{D}^0 D^{*+}$ and obtain the total width of the $Z_c^\pm(3900)$. The numerical results support assigning the $Z_c^\pm(3900)$ to be the diquark-antidiquark type axialvector tetraquark state, and assigning the $Z_c^\pm(3885)$ to be the meson-meson type axialvector molecular state.

hep-ph↗
arXiv2017

Analysis of the $\frac{3}{2}^{\pm}$ pentaquark states in the diquark model with QCD sum rules

In this article, we construct the scalar-diquark-axialvector-diquark-antiquark type interpolating currents, and study the masses and pole residues of the $J^{P}=\frac{3}{2}^{\pm}$ hidden-charmed pentaquark states with the QCD sum rules. 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 obtain the masses of the hidden-charm pentaquark states with the strangeness $S=-1$ and $S=-2$, which can be confronted to the experimental data in the future.

hep-ph↗
arXiv2017

Revisit assignments of the new excited $Ω_c$ states with QCD sum rules

In this article, we distinguish the contributions of the positive parity and negative parity $Ω_c$ states, study the masses and pole residues of the 1S, 1P, 2S and 2P $Ω_c$ states with the spin $J=\frac{1}{2}$ and $\frac{3}{2}$ using the QCD sum rules in a consistent way, and revisit the assignments of the new narrow excited $Ω_c^0$ states. The predictions support assigning the $Ω_c(3000)$ to be the 1P $Ω_c$ state with $J^P={\frac{1}{2}}^-$, assigning the $Ω_c(3090)$ to be the 1P $Ω_c$ state with $J^P={\frac{3}{2}}^-$ or the 2S $Ω_c$ state with $J^P={\frac{1}{2}}^+$, and assigning $Ω_c(3119)$ to be the 2S $Ω_c$ state with $J^P={\frac{3}{2}}^+$.

hep-ph↗