arXiv subjects

Zhi-Gang Wang

Publications and source records attributed to Zhi-Gang Wang.

At least 91 records · Page 5Linked to original sources

arXiv2023

Analysis of the $T_{c\bar{s}}(2900)$ and related tetraquark states with the QCD sum rules

In this research, we tentatively assign the $T_{c\bar{s}}(2900)$ as the $A\bar{A}$-type tetraquark state, and study the mass spectrum of the tetraquark states with strange and doubly strange, which have the spin-parity $J^P = 0^+$, $1^+$ and $2^+$, in the framework of the QCD sum rules in details, where the $A$ denotes the axialvector diquark state. The predicted mass $M=2.92\pm0.12\,\rm{GeV}$ is in consistent with the experimental values $M=2.892\pm0.014\pm0.015\,\rm{GeV}$ and $2.921\pm0.017\pm0.020\,\rm{GeV}$ from the LHCb collaboration and supports assigning the $T_{c\bar{s}}(2900)$ to be the $A\bar{A}$-type scalar $c\bar{s}q\bar{q}$ tetraquark state. The predictions for other tetraquark states can be confronted to the experimental data in the future to diagnose the nature of the fully open flavor exotic states.

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arXiv2023

Systematic analysis of single heavy baryons $Λ_{Q}$, $Σ_{Q}$ and $Ω_{Q}$

Motivated by great progresses in experiments in searching for the heavy baryons, we systematically analyze the mass spectra and root mean square radius of single heavy baryons $Λ_{Q}$, $Σ_{Q}$ and $Ω_{Q}$. The calculations of the mass spectra are carried out in the frame work of Godfrey-Isgur (GI) relativized quark model, where the baryon is regarded as a three-body system of quarks. Our results show that the mass of single heavy baryon with $λ$-mode is lower than those of the $ρ$-mode and $λ$-$ρ$ mixing mode, which indicates that the lowest state is dominated by the $λ$-mode. Basing on this research, we systematically calculate the mass spectra and the root mean square radius of the baryons with $λ$ excited mode. With these predicated mass spectra, the Regge trajectories in the ($J$,$M^{2}$) plane are constructed, and the slopes, intercepts of the Regge trajectories are obtained by linear fitting. It is found that all available experimental data are well reproduced by model predictions and fit nicely to the constructed Regge trajectories.

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arXiv2023

The $S$- and $P$-wave fully charmed tetraquark states and their radial excitations

Inspired by recent progresses in observations of the fully charmed tetraquark states by LHCb, CMS, and ATLAS Collaborations, we perform a systematic study of the ground states and the first radial excitations of the $S$- and $P$-wave $\mathrm{cc}\bar{\mathrm{c}}\bar{\mathrm{c}}$ system. Their mass spectra, root mean square(r.m.s.) radii and radial density distributions are studied with the relativized quark model. The calculations show that there is no stable bound states for the full-charmed tetraquark states, and the r.m.s. radii of these tetraquark states are smaller than 1 fm. Our results support assigning X(6600) structure, $M_{X(6600)}=6552\pm10\pm12$ MeV, as one of the $0^{++}$(1$S$) and $2^{++}$(1$S$) states or their mixtures. Another structure also named as X(6600) by CMS Collaboration, $M_{X(6600)}=6.62\pm0.03^{+0.02}_{-0.01}$ GeV, may arise from the lowest 1$P$ states with $J^{PC}$=$0^{-+}$, $1^{-+}$, and $2^{-+}$. The possible assignments for X(6900) include the $0^{++}$(2$S$), $2^{++}$(2$S$) states, and the highest 1$P$ state with $J^{PC}=0^{-+}$. As for X(7200), it can be interpreted as one of the highest 2$P$ states with $J^{PC}=0^{-+}$, $1^{-+}$, and $2^{-+}$, and the 3$S$ states can not be completely excluded from the candidates.

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arXiv2023

Mass spectra of bottom-charm baryons

In this paper, we investigate the mass spectra of bottom-charm baryons systematically, where the relativistic quark model and the infinitesimally shifted Gaussian basis function method are employed. Our calculation shows that the $ρ$-mode appears lower in energy than the other excited modes. According to this feature, the allowed quantum states are selected and a systematic study of the mass spectra for $Ξ_{bc}^{'}$ ($Ξ_{bc}$) and $Ω_{bc}^{'}$ ($Ω_{bc}$) families is performed. The root mean square radii and quark radial probability density distributions of these baryons are analyzed as well. Next, the Regge trajectories in the $(J,M^{2})$ plane are successfully constructed based on the mass spectra. At last, we present the structures of the mass spectra, and analyze the difficulty and opportunity in searching for the ground states of bottom-charm baryons in experiment.

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arXiv2023

Mass spectra of double-bottom baryons

Based on the relativistic quark model and the infinitesimally shifted Gaussian basis function method, we investigate the mass spectra of double bottom baryons systematically. In the $ρ$-mode which appears lower in energy than the other excited modes, we obtain the allowed quantum states and perform a systematic study of the mass spectra of the $Ξ_{bb}$ and $Ω_{bb}$ families. We analyze the root mean square radii and quark radial probability density distributions to deeply understand the structure of the heavy baryons. Meanwhile, the mass spectra allow us to successfully construct the Regge trajectories in the $(J,M^{2})$ plane. We also predict the masses of the ground states of double bottom baryons and discuss the differences between the structures of our spectra and those from other theoretical methods. At last, the shell structure of the double bottom baryon spectra is shown, from which one could get a bird's-eye view of the mass spectra.

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arXiv2023

Systematic analysis of strange single heavy baryons $Ξ_{c}$ and $Ξ_{b}$

Motivated by the experimental progress in the study of heavy baryons, we investigate the mass spectra of strange single heavy baryons in the $λ$-mode, where the relativistic quark model and the infinitesimally shifted Gaussian basis function method are employed. It is shown that the experimental data can be well reproduced by the predicted masses. The root mean square radii and radial probability density distributions of the wave functions are analyzed in detail. Meanwhile, the mass spectra allow us to successfully construct the Regge trajectories in the $(J,M^{2})$ plane. We also preliminarily assign quantum numbers to the recently observed baryons, including $Ξ_{c}(3055)$, $Ξ_{c}(3080)$, $Ξ_{c}(2930)$, $Ξ_{c}(2923)$, $Ξ_{c}(2939)$, $Ξ_{c}(2965)$, $Ξ_{c}(2970)$, $Ξ_{c}(3123)$, $Ξ_{b}(6100)$, $Ξ_{b}(6227)$, $Ξ_{b}(6327)$ and $Ξ_{b}(6333)$. At last, the spectral structure of the strange single heavy baryons is shown. Accordingly, we predict several new baryons that might be observed in forthcoming experiments.

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arXiv2023

Analysis of the strong coupling constant $G_{D_{s}^{}D_{s}ϕ}$ and the decay width of $D_{s}^{}\rightarrow D_{s}γ$ with QCD sum rules

In this article, we calculate the form factors and the coupling constant of the vertex $D_{s}^{*}D_{s}ϕ$ using the three-point QCD sum rules. We consider the contributions of the vacuum condensates up to dimension $7$ in the operator product expansion(OPE). And all possible off-shell cases are considered, $ϕ$, $D_{s}$ and $D_{s}^{*}$, resulting in three different form factors. Then we fit the form factors into analytical functions and extrapolate them into time-like regions, which giving the coupling constant for the process. Our analysis indicates that the coupling constant for this vertex is $G_{Ds*Dsϕ}=4.12\pm0.70 GeV^{-1}$. The results of this work are very useful in the other phenomenological analysis. As an application, we calculate the coupling constant for the decay channel $D_{s}^{*}\rightarrow D_{s}γ$ and analyze the width of this decay with the assumption of the vector meson dominance of the intermediate $ϕ(1020)$. Our final result about the decay width of this decay channel is $Γ=0.59\pm0.15keV$.

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arXiv2023

Going in quest of potential tetraquark interpretations for the newly observed $T_{ψψ}$ states in light of the diquark-antidiquark scenarios

Stimulated by the recent experimental progress on the $T_{ψψ}$ states, the fully charmed tetraquark spectroscopy is systemically investigated by dint of the Godfrey-Isgur relativized diquark model, the modified Godfrey-Isgur relativized diquark model with the color screening effects, and the nonrelativistic diquark model. The theoretical results of the diquark-antidiquark scenarios propose to interpret the $T_{ψψ}(6200)$, $T_{ψψ}(6600)$, $T_{ψψ}(6900)$, and $T_{ψψ}(7300)$ structures as the candidates of the $1S$-wave, $1P/2S$-wave, $1D/2P$-wave, and $2D/3P/4S$-wave fully charmed tetraquark states, respectively. On account of the deficiency of sufficient experimental information, e.g., the parities of the newly observed $T_{ψψ}$ states, there are uncertainties about the assignments of the $T_{ψψ}(6600)$, $T_{ψψ}(6900)$, and $T_{ψψ}(7300)$ states. It is demonstrated that the further experimental survey on the $cc\bar c\bar c$ states, implemented by the LHCb, ATLAS, CMS, and other collaborations, ought to be continued in the future.

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arXiv2022

Analysis of the $X(3960)$ and related tetraquark molecular states via the QCD sum rules

In this work, we study the $D\bar{D}$, $DD$, $D\bar{D}_s$, $DD_s$, $D_s\bar{D}_s$ and $D_sD_s$ tetraquark molecular states with the $J^{PC}=0^{++}$ via the QCD sum rules. The prediction $M_{D_s\bar {D}_s} = 3.98\pm0.10\, \rm{GeV}$ is in very good agreement with the experimental value $M_{X(3960)} = 3956 \pm 5\pm 10 \,\rm{MeV}$ from the LHCb collaboration and supports assigning the $X(3960)$ as the $D_s^+D_s^-$ molecular state with the $J^{PC}=0^{++}$. We take account of our previous works on the four-quark states consisting of two color-neutral clusters, and acquire the mass spectrum of the ground state hidden-charm and doubly-charm tetraquark molecular states.

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arXiv2022

Study of isospin eigenstates of the pentaquark molecular states with strangeness

In the paper, we construct eight color singlet-singlet type five-quark currents with distinguished isospins to study the $\bar{D}Ξ^{\prime}$, $\bar{D}Ξ_c^{*}$, $\bar{D}^{*}Ξ_c^{\prime}$ and $\bar{D}^{*}Ξ_c^{*}$ molecular states with strangeness via the QCD sum rules. Numerical results show that the central values of the pentaquark masses with higher (lower) isospin are slightly above (below) the thresholds of the corresponding meson-baryon pairs, and support assigning the $P_{cs}(4459)$ as the $\bar{D}Ξ_c^{*}$ molecular state with the quantum numbers $IJ^P=0{\frac{3}{2}}^-$. The other predictions can be confronted to the experimental data in the future.

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arXiv2022

Analysis of the $P_{cs}(4338)$ and related pentaquark molecular states via the QCD sum rules

In this work, we tentatively identify the $P_{cs}(4338)$ as the $\bar{D}Ξ_c$ molecular state, and distinguish the isospins of the current operators to explore the $\bar{D}Ξ_c$, $\bar{D}Λ_c$, $\bar{D}_sΞ_c$, $\bar{D}_sΛ_c$, $\bar{D}^*Ξ_c$, $\bar{D}^*Λ_c$, $\bar{D}^*_sΞ_c$ and $\bar{D}^*_sΛ_c$ molecular states without strange, with strange and with double strange in the framework of the QCD sum rules in details. The present explorations favor identifying the $P_{cs}(4338)$ ($P_{cs}(4459)$) as the $\bar{D}Ξ_c$ ($\bar{D}^*Ξ_c$) molecular state with the spin-parity $J^P={\frac{1}{2}}^-$ (${\frac{3}{2}}^-$) and isospin $(I,I_3)=(0,0)$, the observation of their cousins with the isospin $(I,I_3)=(1,0)$ in the $J/ψΣ^0/η_cΣ^0$ invariant mass distributions would decipher their inner structures.

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arXiv2022

Analysis of the $X(6600)$, $X(6900)$, $X(7300)$ and related tetraquark states with the QCD sum rules

In this work, we re-investigate the mass spectrum of the ground state, first, second and third radial excited states of the diquark-antidiquark type fully-charm tetraquark states with the QCD sum rules plus Regge trajectories. We take account of the CMS and ATLAS experimental data and preform a self-consistent analysis, then try to make possible assignments of the $X(6600)$, $X(6900)$ and $X(7300)$ in the picture of tetraquark states with the $J^{PC}=0^{++}$ or $1^{+-}$.

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arXiv2022

Fully-heavy hexaquark states via the QCD sum rules

We construct the diquark-diquark-diquark type vector six-quark currents to investigate the vector and scalar hexaquark states in the framework of the QCD sum rules in a consistent way, and make predictions for the hexaquark masses. We can search for the fully-heavy hexaquark states in the di-$ Ω_{ccc}$ and di-$ Ω_{bbb}$ invariant mass spectra in the future. Combined with our previous works on the fully-heavy tetraquark states and pentaquark states, the present predictions can shed light on the nature of the fully-heavy multiquark states.

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arXiv2022

The strange cousin of the $Z_c(4020/4025)$ as tetraquark state

Motivated by the analogous properties of the $Z_c(3900/3885)$ and $Z_{cs}(3985/4000)$, we tentatively assign the $Z_c(4020/4025)$ as the $A\bar{A}$-type hidden-charm tetraquark state with the $J^{PC}=1^{+-}$, where the $A$ denotes the axialvector diquark states, and explore the $A\bar{A}$-type tetraquark states without strange, with strange and with hidden-strange via the QCD sum rules in a consistent way. Then we explore the hadronic coupling constants in the two-body strong decays of the tetraquark states without strange and with strange via the QCD sum rules based on rigorous quark-hadron duality, and acquire the partial decay widths and total decay widths. The present calculations support assigning the $Z_c(4020/4025)$ as the $A\bar{A}$-type tetraquark state with the $J^{PC}=1^{+-}$, while the predictions for its strange cousin $Z_{cs}$ state can be confronted to the experimental data in the future.

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arXiv2022

The decay widths of the $Z_{cs}(3985/4000)$ based on rigorous quark-hadron duality

In this work, we explore the hadronic coupling constants $G_{ZJ/ψK}$, $G_{Zη_c K^*}$, $G_{ZD^* \bar{D}_s}$ of the exotic states $Z_{cs}(3985/4000)$ both in the pictures of the tetraquark states and molecular states with the tentative assignments $J^{PC}=1^{+-}$ based on the rigorous quark-hadron duality. Then we obtain the total widths $Γ_{Z_{cs}}^T =15.31\pm 2.06\,\rm{MeV}$ and $Γ_{Z_{cs}}^M=83.51\pm21.09\,\rm{MeV}$, which are consistent with the experimental data $13.8^{+8.1}_{-5.2}\pm4.9\,\rm{MeV}$ from the BESIII collaboration and $131 \pm 15 \pm 26\,\rm{MeV}$ from the LHCb collaboration, respectively, and support assigning the $Z_{cs}(3985)$ and $Z_{cs}(4000)$ to be the hidden-charm tetraquark state and molecular state with the $J^{PC}=1^{+-}$, respectively.

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arXiv2022

Analysis of the doubly-charmed tetraquark molecular states with the QCD sum rules

In the present work, we investigate the scalar, axialvector and tensor doubly-charmed tetraquark molecular states without strange, with strange and with doubly-strange via the QCD sum rules, and try to make assignment of the $T^+_{cc}$ from the LHCb collaboration in the scenario of molecular states. The predictions favor assigning the $T^+_{cc}$ to be the lighter $DD^{*}$ molecular state with the spin-parity $J^P=1^+$ and isospin $I=0$, while the heavier $DD^{*}$ molecular state with the spin-parity $J^P=1^+$ and isospin $I=1$ still escapes experimental detections, the observation of the heavier $DD^{*}$ molecular state would shed light on the nature of the $T_{cc}^+$. All the predicted doubly-charmed tetraquark molecular states can be confronted to the experimental data in the future.

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arXiv2022

Search for the charmed baryonium and dibaryon structures via the QCD sum rules

In the present work, we construct eight six-quark currents to study the $Σ_c\barΣ_c$ baryonium and $Σ_cΣ_c$ dibaryon states via the QCD sum rules. For either $Σ_c\barΣ_c$ baryonium or $Σ_cΣ_c$ dibaryon states, we construct four currents with the $J^P=1^-, 1^+, 0^+$ and $0^-$. Except the current $1^+$ of $Σ_cΣ_c$, we find the Borel windows for the other seven. There are two possible $Σ_c\barΣ_c$ molecular states or compact six-quark states with the $J^P=1^-$ and $0^-$. The results of the current $0^+$ of $Σ_cΣ_c$ show a possible $Σ_cΣ_c$ molecular state with $20$ MeV binding energy. We find two $Σ_c\barΣ_c$ baryonium resonances states with the $J^P=1^+, 0^+$ and two $Σ_cΣ_c$ dibaryon resonances states with the $J^P=0^-, 1^-$, respectively. Pole residues of the seven states are also calculated.

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arXiv2022

Isospin eigenstates of the color singlet-singlet type pentaquark states

In this article, we construct the color singlet-singlet type five-quark currents with the isospins $(I,I_3)=(\frac{1}{2},\frac{1}{2})$ and $(\frac{3}{2},\frac{1}{2})$ unambiguously to explore the $\bar{D}Σ_c$, $\bar{D}Σ_c^*$, $\bar{D}^*Σ_c$ and $\bar{D}^*Σ_c^*$ pentaquark states via the QCD sum rules for the first time, where the $\bar{D}$, $Σ_c$, $\cdots$ represent the color-singlet clusters having the same quantum numbers as the corresponding physical mesons or baryons. The numerical results support assigning the $P_c(4312)$, $P_c(4380)$, $P_c(4440)$ and $P_c(4457)$ as the $\bar{D}Σ_c$, $\bar{D}Σ_c^*$, $\bar{D}^*Σ_c$ and $\bar{D}^*Σ_c^*$ pentaquark states with the isospin $I=\frac{1}{2}$, respectively. The corresponding $\bar{D}Σ_c$, $\bar{D}Σ_c^*$, $\bar{D}^*Σ_c$ and $\bar{D}^*Σ_c^*$ pentaquark states with the isospin $I=\frac{3}{2}$ have slightly larger masses, the observations of the higher pentaquark candidates in the $J/ψΔ$ invariant mass spectrum would shed light on the nature of the $P_c$ states, and make contributions in distinguishing the scenarios of color antitriplet-antitriplet-antitriplet type and color singlet-singlet type pentaquark states.

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