arXiv subjects

Zhi-Gang Wang

Publications and source records attributed to Zhi-Gang Wang.

At least 55 records · Page 3Linked to original sources

arXiv2025

Analysis of the hadronic molecules $DK$, $D^K$, $DK^$ and their bottom analogs with QCD sum rules

In this work, we construct the color-singlet-color-singlet type currents to study the masses and pole residues of charm-strange tetraquark states and their bottom analogs with $J^P$ = $0^+$ and $1^+$ by using two-point QCD sum rules, where the vacuum condensates are considered up to dimension 12. The predicted masses for $DK$, $D^*K$ and $DK^*$ molecular states are $2.322_{ - 0.072}^{ + 0.066}$ GeV, $2.457_{ - 0.068}^{ + 0.064}$ GeV and $2.538_{ - 0.062}^{ + 0.059}$ GeV. These results are consistent well with the experimental data of $D_{s0}(2317)$, $D_{s1}(2460)$ and ${D}_{s1}(2536)$, respectively. The theoretical results for $BK$ and $B^*K$ molecular states are $5.970_{ - 0.064}^{ + 0.061}$ GeV and $6.050_{ - 0.064}^{ + 0.062}$ GeV which are all higher than their own thresholds. Finally, the mass of hadronic molecule $BK^*$ is predicted to be $6.158_{ - 0.063}^{ + 0.061}$ GeV. This value is lower than the threshold of $BK^*$, which implies that it may be a bound hadronic molecular state.

hep-ph↗

arXiv2025

Prescribing hyperbolic bordered surfaces via combinatorial flows

The aim of this paper is to investigate the fractional combinatorial Calabi flow for hyperbolic bordered surfaces. By Lyapunov theory, it is proved that the flow exists for all time and converges exponentially to a conformal factor that generates a hyperbolic surface whose lengths of boundary components are prescribed positive numbers. Furthermore, a generalized combinatorial Yamabe flow is introduced in the same geometry setting, with the long time existence and convergence established. This result yields an algorithm for searching bordered surfaces, which may accelerate convergence speed.

math.CV↗

arXiv2025

Mass spectra of singly heavy baryons in the relativized quark model with heavy-quark dominance

The rigorous calculation of the spin-orbit terms in the three-quark system is realized based on the Gaussian expansion method and the infinitesimally-shifted Gaussian basis functions in the frame work of the relativized quark model, by ignoring the mixing between different excited states. Then, the complete mass spectra of the singly heavy baryons are obtained rigorously, under the mechanism of the heavy-quark dominance. On these bases, the systematical analyses are carried out for the reliability and predictive power of the model, the fine structure of the singly heavy baryon spectra, the assignments of the excited baryons, and some important topics about the heavy baryon spectroscopy such as the missing states, the `spin-orbit puzzle', the clustering effect, etc. The result confirms that under the heavy-quark dominance mechanism, the relativized quark model can describe the excitation spectra and the fine structures of the singly heavy baryons correctly and precisely.

hep-ph↗

arXiv2025

Analysis of the $X(4475/4710)$, $X(4500/4700)$, $Z_{c}(4600)$, $Z_{\bar{c}\bar{s}}(4600)$ and related tetraquark states with the QCD sum rules

In this work, we introduce an explicit P-wave to construct the diquarks $[qc]_{\widehat{V}}$, then construct the local four-quark currents to explore the hidden-charm tetraquark states with the $J^{PC}=0^{++}$, $1^{+-}$ and $2^{++}$ in the framework of the QCD sum rules at length. Our calculations indicate that the light-flavor $SU(3)$ breaking effects on the tetraquark masses are tiny. The predictions support assigning the $X(4475)$ and $X(4500)$ as the $[uc]_{\widehat{V}}[\overline{uc}]_{\widehat{V}}-[dc]_{\widehat{V}}[\overline{dc}]_{\widehat{V}}$ and $[sc]_{\widehat{V}}[\overline{sc}]_{\widehat{V}}$ tetraquark states with the $J^{PC}=0^{++}$ respectively, and assigning the $Z_{c}(4600)$ and $Z_{\bar{c}\bar{s}}(4600)$ as the $[uc]_{\widehat{V}}[\overline{dc}]_{\widehat{V}}$ and $[qc]_{\widehat{V}}[\overline{sc}]_{\widehat{V}}$ tetraquark states with the $J^{PC}=1^{+-}$ respectively. On the other hand, there is no room for the $X(4710)$ and $X(4700)$. Combined with previous works, the $X(4475)$, $X(4500)$, $Z_{c}(4600)$ and $Z_{\bar{c}\bar{s}}(4600)$ might have other important Fock components besides the $\widehat{V}\widehat{V}$ type components.

hep-ph↗

arXiv2025

Systematic analysis of the mass spectra of triply heavy baryons

The mass spectra, root mean square (r.m.s.) radii and radial density distributions of $Ω_{ccb}$ and $Ω_{bbc}$ baryons are firstly analyzed in the present work. The calculations are carried out in the frame work of relativized quark model, where the baryon is regarded as a real three-quark system. Our results show that the excited energy of charmed-bottom triply baryons are always associated with heavier quark. This means the lowest state of $Ω_{ccb}$ baryon is dominated by the $λ$-mode, however, the dominant orbital excitation for $Ω_{bbc}$ baryon is $ρ$-mode. In addition, the influence of configuration mixing on mass spectrum, which is induced by different angular momentum assignments, is also analyzed. It shows that energy of the lowest state will be further lowered by this mixing effect. According to this conclusion, we systematically analyze the mass spectra of the ground and excited states($1S\sim4S$, $1P\sim4P$, $1D\sim4D$, $1F\sim4F$ and $1G\sim4G$) of $Ω_{ccb}$, $Ω_{bbc}$, $Ω_{ccc}$ and $Ω_{bbb}$ baryons. Finally, with the predicated mass spectra, the Regge trajectories of these heavy baryons in the ($J$,$M^{2}$) plane are constructed.

hep-ph↗

arXiv2025

Two-body strong decays of the hidden-charm tetraquark molecular states via the QCD sum rules

In this work, we extend our previous work on the $D^*\bar{D}^*$ molecular states with the $J^{PC}=0^{++}$, $1^{+-}$ and $2^{++}$ to investigate their two-body strong decays via the QCD sum rules based on rigorous quark-hadron duality. We obtain the partial decay widths therefore total widths of the ground states with the $J^{PC}=0^{++}$, $1^{+-}$ and $2^{++}$, which indicate that it is reasonable to assign the $X_2(4014)$ as the $D^*\bar{D}^*$ tetraquark molecular states with the $J^{PC}=2^{++}$.

hep-ph↗

arXiv2025

Mass spectrum of the hidden-charm hybrid states via the QCD sum rules

In this work, we study the mass spectrum of the hidden-charm hybrid states with the $J^{PC}=0^{-+}$, $0^{++}$, $0^{--}$, $1^{++}$, $1^{+-}$, $1^{-+}$, $1^{--}$, $2^{-+}$ and $2^{++}$ via the QCD sum rules in a consistent way. We calculate the vacuum condensates up to dimensions-6 by taking account of both the leading order and next-to-leading order contributions, and take the energy scale formula $μ=\sqrt{M^2_{X/Y/Z}-(2{\mathbb{M}}_c)^2}$ to choose the suitable energy scales of the QCD spectral densities, it is the first time to explore the energy scale dependence of the QCD sum rules for the hidden-charm hybrid states.

hep-ph↗

arXiv2025

Strong decays of the fully-charm tetraquark states with explicit P-waves via the QCD sum rules

We introduce a relative P-wave to construct the vector doubly-charm diquark $(\widetilde{V})$, therefore, the scalar and tensor four-quark currents to investigate the decay widths of the fully-charm tetraquark states with the $J^{PC}=0^{++}$, $1^{+-}$ and $2^{++}$ via the QCD sum rules. We observe that the total width of the ground state $\widetilde{V}\overline{\widetilde{V}}$-type scalar tetraquark state is compatible with that of the $X(6552)$ within the uncertainties, and the branching ratios are quite different from that of the first radial excitation of the $A\bar{A}$-type scalar tetraquark state. Other predictions can be verified in the future experiments to shed light on the nature of the fully-charm tetraquark states.

hep-ph↗

arXiv2025

Hunting for the prospective $T_{cc}$ family based on the diquark-antidiquark configuration

Inspired by the first $T_{cc}$ observation at the LHCb Collaboration, the spectroscopic properties of the entire isoscalar and isovector $T_{cc}$ family are systematically investigated by means of multiple sorts of relativized and nonrelativistic diquark formalisms, which include the Godfrey-Isgur relativized diquark model, the modified Godfrey-Isgur relativized diquark model incorporating the color screening effects, the nonrelativistic diquark model with the Gaussian type hyperfine potential, and the nonrelativistic diquark model with the Yukawa type hyperfine potential. In terms of the $1S$-wave double-charm tetraquark state with $I(J^P)=0(1^+)$, the predicted masses of most diquark-antidiquark scenarios are somewhat higher than the observed value of the $T_{cc}(3875)^+$ structure. In light of the diquark-antidiquark configuration, this work unveils the mixing angles of the orbitally excited isovector $T_{cc}$ states and the magic mixing angles of the ideal heavy-light tetraquarks for the first time. As the advancement of the experimental detection capability, these phenomenological predictions will effectively boost the hunting for the prospective low-lying $T_{cc}$ states in the future.

hep-ph↗

arXiv2024

Heavy-quark dominance and fine structure of excited heavy baryons $Σ_{Q}$, $Ξ'_{Q}$ and $Ω_{Q}$

In the framework of the relativized quark model, the calculation of spin-orbit interactions is improved by considering the contribution from the light quark cluster in a singly heavy baryon. It modifies the energy level splitting of the orbital excitation significantly and causes the emergence of fine structures for $Σ_{Q}$, $Ξ'_{Q}$ and $Ω_{Q}$ baryons. Based on this improvement, we systematically analyze the fine structures and retest the heavy quark dominance mechanism. This mechanism is found to be violated in the $1P$-wave states of the $Σ_{c}$, $Ξ'_{c}$ and $Ω_{c}$ baryons although it remains effective overall, which may help to understand the nature of the heavy quarks and strong interactions. With the predicted fine structures, we make the precise assignments of those observed heavy baryons which once could not be accurately explained due to their close mass values. The method used in this work is instructive and applicable for the study of more complex exotic hadrons, such as the heavy tetraquarks and pentaquarks.

hep-ph↗

arXiv2024

Analysis of the form factors of $B_c\rightarrow D^{()}$, $D_{s}^{()}$ and their nonleptonic decays

This article is devoted to calculating the form factors of $B_c \to D^{*}$, $B_c \to D$, $B_c \to D_s^{*}$ and $B_c \to D_s$ transitions in the framework of three-point QCD sum rules. At the QCD side, the contributions of $\langle\overline{q}q\rangle$, $\langle\overline{q}g_{s}σGq\rangle$, $\langle g_{s}^{2}G^{2}\rangle$, $\langle f^{3}G^{3}\rangle$ and $\langle\overline{q}q\rangle \langle g_{s}^{2}G^{2}\rangle$ are taken into account. With the obtained form factors, the decay widths and branching ratios of several two-body nonleptonic decay processes $B_c \to η_c D^{*}$, $η_c D$, $ J/ψD^{*}$, $ J/ψD$, $η_c D_s^{*}$, $η_c D_s$, $J/ψD_s^{*}$ and $J/ψD_s$ are predicted. These results about the form factors and decay properties of $B_c$ meson provide useful information for us to study the heavy-quark dynamics.

hep-ph↗

arXiv2024

The ground states of hidden-charm tetraquarks and their radial excitations

Inspired by the great progress in the observations of charmonium-like states in recent years, we perform a systematic analysis about the ground states and the first radially excited states of $qc\bar{q}\bar{c}$ ($q$=$u/d$ and $s$) tetraquark systems. Their mass spectra, root mean square (r.m.s.) radii and radial density distributions are predicted within the framework of relativized quark model. By comparing with experimental data, some potential candidates for hidden-charm tetraquark states are suggested. For $qc\bar{q}\bar{c}$ ($q$=$u/d$) system, if $Z_{c}(3900)$ is supposed to be a compact tetraquark state with $J^{PC}=1^{+-}$, $Z(4430)$ can be interpreted as the first radially excited states of $Z_{c}(3900)$. Another broad structure $Z_{c}(4200)$ can also be explained as a partner of $Z_{c}(3900)$, and it arise from a higher state with $J^{PC}=1^{+-}$. In addition, theoretical predictions indicate that the possible assignments for $X(3930)$, $X(4050)$ and $X(4250)$ are low lying $0^{++}$ tetraquark states. As for the $sc\bar{s}\bar{c}$ system, $X(4140)$ and $X(4274)$ structures can be interpreted as this type of tetraquark states with $J^{PC}=1^{++}$, and $X(4350)$ can be described as a $sc\bar{s}\bar{c}$ tetraquark with $J^{PC}=0^{++}$. With regard to $qc\bar{s}\bar{c}$ ($q$=$u/d$) system, we find two potential candidates for this type of tetraquark, which are $Z_{cs}(4000)$ and $Z_{cs}(4220)$ structures. The measured masses of these two structures are in agreement with theoretical predictions for the $1^{+}$ state.

hep-ph↗

arXiv2024

Analysis of the hidden-charm-hidden-strange tetraquark mass spectrum via the QCD sum rules

In the present work, we construct the diquark-antidiquark type four-quark currents to investigate the mass spectrum of the ground state hidden-charm-hidden-strange tetraquark states with the quantum numbers $J^{PC}=0^{++}$, $1^{+-}$, $1^{++}$ and $2^{++}$ via the traditional QCD sum rules in a comprehensive way. We update old calculations, perform new calculations and analysis in a rigorous way, and take account of the net light-flavor $SU(3)$ breaking effects in a consistent way. And we make more reasonable identifications for the $X(3960)$, $X(4140)$, $X(4274)$, $X(4500)$, $X(4685)$ and $X(4700)$ and supersede some old identifications. Furthermore, we consider our previous theoretical predictions, and make reasonable/suitable identifications of the new LHCb states $h_c(4000)$ and $χ_{c1}(4010)$.

hep-ph↗

arXiv2024

Systematic analysis of the form factors of $B_c\rightarrowη_c$, $J/ψ$ and corresponding weak decays

The form factors of $B_c\rightarrowη_c$ and $B_c\rightarrow J/ψ$ are analyzed in the framework of three-point QCD sum rules. In these analyses, the contributions of the vacuum condensate terms $\langle g_{s}^{2}GG\rangle$ and $\langle g_{s}^{3}GGGf\rangle$ are considered. In addition, the decay widths and branching ratios of several decay channels are obtained by using the calculated form factors. These decay processes include the nonleptonic decays of $B_c^- \to η_c π^-$, $η_c K^-$, $η_c ρ^-$, $η_c K^{*-}$, $B_c^- \to J/ψπ^-$, $J/ψK^-$, $J/ψρ^-$, $J/ψK^{*-}$, and the semileptonic decays of $B_c^- \to η_c \mathcal{l} \barν$, $B_c^- \to J/ψ\mathcal{l} \barν$. These results about the form factors and decay properties of $B_c$ meson provide useful information for us to study the heavy-quark dynamics and find new physics(NP) beyond Standard Model(SM).

hep-ph↗

arXiv2024

The $B_c$ meson and its scalar cousin with the QCD sum rules

In the present work, we use optical theorem to calculate the next-to-leading order corrections to the QCD spectral densities directly in the QCD sum rules for the pseudoscalar and scalar $B_c$ mesons. We take the experimental data as guides to perform updated analysis, and obtain the masses and decay constants, especially the decay constants, which are the fundamental input parameters in the high energy physics, therefore the pure leptonic decay widths, which can be confronted to the experimental data in the future.

hep-ph↗

arXiv2024

The ground states and first radial excitations of the vector tetraquark states with explicit P-waves via the QCD sum rules

In this work, we choose the diquark-antidiquark type four-quark currents with an explicit P-wave between the diquark and antidiquark pairs to study the ground states and first radial excitations of the hidden-charm tetraquark states with the quantum numbers $J^{PC}=1^{--}$. And we obtain the lowest vector tetraquark masses and make possible assignments of the existing $Y$ states. There indeed exists a hidden-charm tetraquark state with the $J^{PC}=1^{--}$ at the energy about $4.75\,\rm{GeV}$ as the first radial excitation to account for the BESIII data.

hep-ph↗

arXiv2024

Strong decays of the $P_{cs}(4338)$ and its high isospin cousin via the QCD sum rules

In the present work, the strong decays of the newly observed $P_{cs}(4338)$ as well as its high isospin cousin $P_{cs}(4460)$ are studied via the QCD sum rules. According to conservation of isospin, spin and parity, the hadronic coupling constants in four decay channels are obtained, then the partial decay widths are obtained. The total width of the $P_{cs}(4338)$ coincides with the experimental data nicely, while the predictions for the $P_{cs}(4460)$ can be testified in the future experiment, and shed light on the nature of the $P_{cs}(4338)$.

hep-ph↗

arXiv2024

Strong decays of the vector tetraquark states with the masses about $4.5\,\rm{GeV}$ via the QCD sum rules

We suppose that there exist three vector hidden-charm tetraquark states with the $J^{PC}=1^{--}$ at the energy about $4.5\,\rm{GeV}$, and investigate the two-body strong decays systematically. We obtain thirty QCD sum rules for the hadronic coupling constants based on rigorous quark-hadron duality, then obtain the partial decay widths, therefore the total widths approximately, which are compatible with the experimental data of the $Y(4500)$ from the BESIII collaboration. The $Y(4500)$ may be one vector tetraquark state having three main Fock components, or consists of three different vector tetraquark states. We can search for the typical decays $ Y \to \frac{\bar{D}^0_1D^{0}-\bar{D}^{0}D^{0}_1}{\sqrt{2}}$, $\frac{\bar{D}^-_1D^{+}-\bar{D}^{-}D^{+}_1}{\sqrt{2}}$, $\frac{\bar{D}^0_0D^{*0}-\bar{D}^{*0}D^{0}_0}{\sqrt{2}}$, $ \frac{\bar{D}^-_0D^{*+}-\bar{D}^{*-}D^{+}_0}{\sqrt{2}}$, $η_cω$, $J/ψω$ to diagnose the nature of the $Y(4500)$.

hep-ph↗