Search

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 $\langle\overline{q}q\rangle$, $\langle\overline{q}g_{s}\sigma Gq\rangle$, $\langle g_{s}^{2}G^{2}\rangle$, $\langle f^{3}G^{3}\rangle$ 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 $B_c \to \eta_c D^{*}$, $\eta_c D$, $ J/\psi D^{*}$, $ J/\psi D$, $\eta_c D_s^{*}$, $\eta_c D_s$, $J/\psi D_s^{*}$ and $J/\psi D_s$ 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.

In this work, we introduce explicit P-waves to construct the diquark operators, 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 tiny light-flavor $SU(3)$ breaking effects on the tetraquark masses due to the special currents and the predictions support assigning the $X(4775)$ 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, and thus account for the LHCb's data., Comment: 12 pages, 2 figures

We systematically study the 1D charmonium spin-triplet (with the $J^{PC}=1^{--}, 2^{--}, 3^{--}$) and spin-singlet (with the $J^{PC}=2^{-+}$) via the QCD sum rules in comparison with the present experimental results. More experimental data will help us to unravel the mass spectrum of the charmonium states near the open-charm thresholds., Comment: 11 pages, 27 figures

We introduce a relative P-wave to construct the vector doubly-charm diquark $(\widetilde{V})$, therefore, the scalar and tensor tetraquark 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 range of 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., Comment: 12 pages, 2 figures

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.

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 unveiled by means of multiple sorts of relativized and nonrelativistic diquark formalisms, encompassing 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. The theoretical outcomes of various diquark-antidiquark scenarios are inclined to categorize the $T_{cc}(3875)^+$ structure as the exemplary candidate of the $1S$-wave isoscalar axial-vector double-charm tetraquark state. In light of the diquark-antidiquark configuration, this work investigates 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., Comment: 24 pages

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 $\chi_{c1}(4010)$., Comment: 21 pages, 1 figure

The form factors of $B_c\rightarrow\eta_c$ and $B_c\rightarrow J/\psi$ 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 $B_c^- \to \eta_c \pi^-$, $\eta_c K^-$, $\eta_c \rho^-$, $\eta_c K^{*-}$, $B_c^- \to J/\psi \pi^-$, $J/\psi K^-$, $J/\psi \rho^-$, $J/\psi K^{*-}$, and the semileptonic decays of $B_c^- \to \eta_c \mathcal{l} \bar{\nu}$, $B_c^- \to J/\psi \mathcal{l} \bar{\nu}$. 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).

We obtain a sharp result on order of certain affine and linear invariant families of harmonic quasiconformal mappings with bounded Schwarzian norm. This problem is motivated by the work of Chuaqui, Hern\'{a}ndez and Mart\'{i}n [Math. Ann. 367: 1099--1122, 2017]. Firstly, for $K\ge1$, we construct a harmonic $K$-quasiconformal counterpart of the classical Koebe function and use it to formulate the corresponding conjectures. Then we consider Hardy spaces $H^p$ of harmonic quasiconformal mappings by applying results for quasiconformal mappings obtained by Astala and Koskela [Pure Appl. Math. Q. 7: 19--50, 2011]. In particular, we determine the optimal order of the family of harmonic quasiconformal mappings with bounded Schwarzian norm to belong to a harmonic Hardy space. This partially solves an open problem posed by Pavlovi\'{c} in 2014. Finally, we derive pre-Schwarzian and Schwarzian norm estimates of certain harmonic mappings., Comment: 20 pages, 6 figures. Comments are welcome

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 $\Sigma_{Q}$, $\Xi '_{Q}$ and $\Omega_{Q}$ 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 $\Sigma_{c}$, $\Xi '_{c}$ and $\Omega_{c}$ 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., Comment: 10 pages, 3 figures, 2 tables

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., Comment: 12 pages, 4 figures

In the present work, the doubly-charm and doubly-bottom pentaquark molecular states $D^{(*)}\Sigma_c^{(*)}$ and $B^{(*)}\Sigma_b^{(*)}$ are studied via the QCD sum rules. Sixteen color singlet-singlet type currents with the definite isospin-spin-parity $IJ^P$ are constructed to interpolate the corresponding hadronic states with the same quantum numbers. The masses and pole residues of those doubly-heavy pentaquark molecular states are calculated, the results show that their masses are all below the corresponding meson-baryon thresholds, which means that they are possible bound states, not resonant states, moreover, the possible decay channels for the doubly-charm molecular states are given., Comment: 12 pages, 10 figures

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 $P_{cs}(4338)$., Comment: 13 pages, 12 figures

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}}$, $\eta_c\omega$, $J/\psi\omega$ to diagnose the nature of the $Y(4500)$., Comment: 28 pages, 1 figure

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., Comment: 15 pages, 10 figures

In this article, we analyze the electromagnetic form factors of the vector heavy-light mesons to the pseudoscalar heavy-light mesons in the framework of three-point QCD sum rules, where the contributions of vacuum condensate terms $\langle\overline{q}q\rangle$, $\langle\overline{q}g_{s}\sigma Gq\rangle$, $\langle g_{s}^{2}G^{2}\rangle$, $\langle f^{3}G^{3}\rangle$ and $\langle\overline{q}q\rangle\langle g_{s}^{2}G^{2}\rangle$ are considered. With these results, we also obtain the radiative decay widths of the vector heavy-light mesons and then compare our results with those of other collaboration's. The final results about the radiative decay widths are $\Gamma(D^{*0}\to D^{0}\gamma)=1.74^{+0.40}_{-0.37}$ keV, $\Gamma(D^{*+}\to D^{+}\gamma)=0.17^{+0.08}_{-0.07}$ keV, $\Gamma(D_{s}^{*}\to D_{s}\gamma)=0.029^{+0.009}_{-0.008}$ keV, $\Gamma(B^{*0}\to B^{0}\gamma)=0.018^{+0.006}_{-0.005}$ keV, $\Gamma(B^{*+}\to B^{+}\gamma)=0.015^{+0.007}_{-0.007}$ keV and $\Gamma(B^{*}_{s}\to B_{s}\gamma)=0.016^{+0.003}_{-0.005}$ keV.

We take the scalar, pseudoscalar, axialvector, vector and tensor diquarks as the basic building blocks to construct the four-quark currents with implicit P-waves, and investigate the hidden-charm-hidden-strange tetraquark states with the $J^{PC}=1^{--}$ and $1^{-+}$ via the QCD sum rules in a comprehensive and consistent way, and revisit the assignments of the $X/Y$ states, especially the $Y(4500)$, $X(4630)$, $Y(4660)$, $Y(4710)$ and $Y(4790)$, in the tetraquark picture., Comment: 15 pages, 4 figures

A mechanism of the heavy quark dominance in the orbital excitation is proposed in this paper which is testified to be reasonable for singly and doubly heavy baryons. In the relativistic quark model, an analysis of the Hamiltonian figures out the mechanism that the excitation mode with lower energy levels is always associated with the heavy quark(s), and the splitting of the energy levels is suppressed by the heavy quark(s). So, the heavy quarks dominate the orbital excitation of singly and doubly heavy baryons. Furthermore, a physical understanding of this mechanism is given in a semi-classical way. Accordingly, the predicted mass spectra of singly and doubly heavy baryons confirm the rationality of this mechanism. In addition, an interesting consequence of this mechanism is that a heavy-light meson is more likely to be produced in the strong decay of the high-orbital excited states, which is supported by experiments. This mechanism is rooted in the breakdown of the mass symmetry. Therefore, it may be also valid for other multi-quark systems, such as the tetraquarks Qqqq and QQqq, or the pentaquarks Qqqqq and QQqqq., Comment: 12 pages, 7 figures, 5 tables

We study the hadronic coupling constants in the two-body strong decays of the fully-charm tetraquark states with the $J^{PC}=0^{++}$, $1^{+-}$ and $2^{++}$ via the QCD sum rules based on rigorous quark-hadron duality. Then we obtain the hadronic coupling constants and partial decay widths therefore total decay widths, which support assigning the $X(6552)$ as the first radial excitation of the scalar tetraquark state. And other predictions can be used to diagnose exotic states in the future., Comment: 17 pages, 3 figures

In this work, we take the $X(3872)$ as the hidden-charm tetraquark state with both isospin $I=0$ and $1$ components, then investigate the strong decays $X(3872)\to J/\psi \pi^+\pi^-$, $J/\psi\omega$, $\chi_{c1}\pi^0$, $D^{*0}\bar{D}^0$ and $D^{0}\bar{D}^0\pi^0$ with the QCD sum rules. We take account of all the Feynman diagrams, and acquire four QCD sum rules based on rigorous quark-hadron duality. We obtain the total decay width about $1\,\rm{MeV}$, which is in excellent agreement with the experiment data $ \Gamma_{X}=1.19\pm 0.21\,\rm{MeV}$ from the Particle Data Group, it is the first time to reproduce the tiny width of the $X(3872)$ via the QCD sum rules, which supports assigning the $X(3872)$ as the hidden-charm tetraquark state with the $J^{PC}=1^{++}$., Comment: 12 pages, 4 figures

We tentatively assign the $Y(4230)$ as the vector tetraquark state with a relative P-wave between the scalar diquark pair, and explore the three-body strong decays $Y(4230) \to \bar{D}^{*-}D^{*0}\pi^+$, $\bar{D}^{*-}D^0\pi^+$, $J/\psi\pi^+\pi^- $ and $ J/\psi K^+K^-$ with the light-cone QCD sum rules by assuming contact four-meson coupling constants. The resulting partial decay widths are too small to account for the experimental data, and we expect those decays take place through an intermediate meson. We can search for the intermediate states and precisely measure the branching fractions to diagnose the nature of the $Y$ states., Comment: 13 pages, 4 figures. arXiv admin note: text overlap with arXiv:2304.14153

In this work, we analyze the strong vertices $\Sigma_{c}\Delta D^{*}$ and $\Sigma_{b}\Delta B^{*}$ using the three-point QCD sum rules under the tensor structures $i\epsilon^{\rho\tau\alpha\beta}p_{\alpha}p'_{\beta}$, $p^{\rho}p'^{\tau}$ and $p^{\rho}p^{\tau}$. We firstly calculate the momentum dependent strong coupling constants $g(Q^{2})$ by considering contributions of the perturbative part and the condensate terms $\langle\overline{q}q\rangle$, $\langle g_{s}^{2}GG \rangle$, $\langle\overline{q}g_{s}\sigma Gq\rangle$ and $\langle\overline{q}q\rangle^{2}$. By fitting these coupling constants into analytical functions and extrapolating them into time-like regions, we then obtain the on-shell values of strong coupling constants for these vertices. The results are $g_{1\Sigma_{c}\Delta D^{*}}=5.13^{+0.39}_{-0.49}$ GeV$^{-1}$, $g_{2\Sigma_{c}\Delta D^{*}}=-3.03^{+0.27}_{-0.35}$ GeV$^{-2}$, $g_{3\Sigma_{c}\Delta D^{*}}=17.64^{+1.51}_{-1.95}$ GeV$^{-2}$, $g_{1\Sigma_{b}\Delta B^{*}}=20.97^{+2.15}_{-2.39}$ GeV$^{-1}$, $g_{2\Sigma_{b}\Delta B^{*}}=-11.42^{+1.17}_{-1.28}$ GeV$^{-2}$ and $g_{3\Sigma_{b}\Delta B^{*}}=24.87^{+2.57}_{-2.82}$ GeV$^{-2}$. These strong coupling constants are important parameters which can help us to understand the strong decay behaviors of hadrons.

In the present work, considering the conservation of isospin in the strong decays, we investigate the strong decays of the pentaquark molecule candidate $P_c(4312)$ and its possible higher isospin cousin $P_c(4330)$ in the framework of the QCD sum rules. What's more, the pole residue of the $\Delta$ baryon with isospin eigenstate $|II_3\rangle=|\frac{3}{2}\frac{1}{2}\rangle$ is obtained. If the possible pentaquark molecule candidate $P_c(4330)$ could be testified in the future experiment, it would shed light on interpretations of the $P_c$ states., Comment: 13 pages, 5 figures

In this work, we systematically investigate the singly-charmed pentaquark molecular states $D^{(*)}N$, $D^{(*)}\Xi^{(*)}$ and $D_s^{(*)}\Xi^{(*)}$ with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 13 and taking fully account of the light-flavor $SU(3)$ breaking effects. The numerical results favor assigning the $\Omega_c(3185)$ as the $D\Xi$ molecular state with the $J^P=\frac{1}{2}^-$ and $| I,I_3 \rangle=| 0,0 \rangle$, assigning the $\Omega_c(3327)$ as the $D^*\Xi$ molecular state with the $J^P=\frac{3}{2}^-$ and $|I,I_3 \rangle=| 0,0 \rangle$, assigning the $\Sigma_c(2800)$ as the $DN$ molecular state with the $J^P=\frac{1}{2}^-$ and $| I,I_3 \rangle=| 1,0 \rangle$, and assigning the $\Lambda_c(2940)/\Lambda_c(2910)$ as the $D^*N$ molecular state with the $J^P=\frac{3}{2}^-$ and $| I,I_3 \rangle=| 0,0 \rangle$. Other potential molecule candidates are also predicted, which may be observed in future experiments. For example, we can search for the $D\Xi$ and $D^*\Xi$ molecular states with the isospin $| I,I_3 \rangle=| 1,\pm1 \,\rangle$ in the $\Xi_c^+\bar{K}^0$ and $\Xi_c^0\bar{K}^-$ mass spectrum respectively in the future, which could shed light on the nature of the $\Omega_c(3185/3327)$., Comment: 23 pages, 6 figures

In this article, the strong coupling constants of vertices $BB\Upsilon$, $BB^{*}\Upsilon$, $B^{*}B^{*}\Upsilon$, $BB^{*}\eta_{b}$ and $B^{*}B^{*}\eta_{b}$ are analyzed in the framework of QCD sum rules. In this work, all possible off-shell cases and the contributions of vacuum condensate terms including $\langle\overline{q}q\rangle$, $\langle\overline{q}g_{s}\sigma Gq\rangle$, $\langle g_{s}^{2}G^{2}\rangle$, $\langle f^{3}G^{3}\rangle$ and $\langle\overline{q}q\rangle\langle g_{s}^{2}G^{2}\rangle$ are considered. The momentum dependent strong coupling constants are first calculated and then are fitted into analytical functions $g(Q^{2})$ which are used to extrapolate into time-like regions to obtain the final values of strong coupling constants. The final results are $g_{BB\Upsilon}=40.67^{+7.55}_{-4.20}$, $g_{BB^{*}\Upsilon}=11.58^{+2.19}_{-1.09}$ GeV$^{-1}$, $g_{B^{*}B^{*}\Upsilon}=57.02^{+5.32}_{-5.31}$, $g_{BB^{*}\eta_{b}}=23.39^{+4.74}_{-2.30}$ and $g_{B^{*}B^{*}\eta_{b}}=12.49^{+2.12}_{-1.35}$ GeV$^{-1}$. These strong coupling constants are important input parameters which reflect the dynamic properties of the interactions among the mesons and quarkonia., Comment: arXiv admin note: text overlap with arXiv:2304.13969

Our study focuses on the $\Lambda$-type P-wave bottom baryon states with the spin-parity $J^P=\frac{1}{2}^-$, $\frac{3}{2}^-$. We introduce an explicit P-wave between the two light quarks in the interpolating currents (and the two light quarks are antisymmetric in flavor space, therefore leads to the name $\Lambda$-type baryon) to investigate the $\Lambda_b$ and $\Xi_b$ states within the framework of the full QCD sum rules. The predicted masses show that the $\Xi_b(6087)$ and $\Xi_b(6095/6100)$ could to be the P-wave bottom-strange baryon states with the spin-parity $J^P=\frac{1}{2}^-$ and $\frac{3}{2}^-$, respectively, meanwhile, the $\Lambda_b(5912)$ and $\Lambda_b(5920)$ could be the P-wave bottom baryon states with the spin-parity $J^P=\frac{1}{2}^-$ and $\frac{3}{2}^-$, respectively. The $\Lambda_b(5920)$ and $\Xi_b(6095/6100)$ maybe have two remarkable under-structures or Fock components at least., Comment: 19 pages, 12 figures, revised version

In this work, we tentatively assign the $Y(4500)$ as the $[uc]_{\tilde{A}}[\overline{uc}]_{V}+[uc]_{V}[\overline{uc}]_{\tilde{A}}+[dc]_{\tilde{A}}[\overline{dc}]_{V} +[dc]_{V}[\overline{dc}]_{\tilde{A}}$ tetraquark state with the quantum numbers $J^{PC}=1^{--}$, and study the three-body strong decay $Y(4500)\to D^{*-}D^{*0}\pi^+$ with the light-cone QCD sum rules. It is the first time to use the light-cone QCD sum rules to calculate the four-hadron coupling constants, the approach can be extended to study other three-body strong decays directly and diagnose the $X$, $Y$ and $Z$ states., Comment: 11 pages, 3 figure

In this work, the strong coupling constants of the vertices $DDJ/\psi$, $DD^{*}J/\psi$, $D^{*}D^{*}J/\psi$, $DD^{*}\eta_{c}$ and $D^{*}D^{*}\eta_{c}$ are calculated within the framework of the QCD sum rules. For each vertex, we analyze the momentum dependence of the coupling constants by considering all possible off-shell cases. In these analyses, we consider the contributions of the vacuum condensate terms $\langle\overline{q}q\rangle$, $\langle\overline{q}g_{s}\sigma Gq\rangle$, $\langle g_{s}^{2}G^{2}\rangle$, $\langle f^{3}G^{3}\rangle$ and $\langle\overline{q}q\rangle\langle g_{s}^{2}G^{2}\rangle$. Then, the momentum dependent coupling constants are fitted into analytical functions $g(Q^2)$ and are extrapolated into time-like regions. The values of strong coupling constants are obtained by using on-shell conditions of the intermediate mesons($Q^2=-m^2$). The final results are as follows, $g_{DDJ/\psi}=5.01^{+0.58}_{-0.16}$, $g_{DD^{*}J/\psi}=3.55^{+0.20}_{-0.21}$GeV$^{-1}$, $g_{D^{*}D^{*}J/\psi}=5.10^{+0.59}_{-0.43}$, $g_{DD^{*}\eta_{c}}=3.68^{+0.39}_{-0.11}$ and $g_{D^{*}D^{*}\eta_{c}}=4.87^{+0.42}_{-0.40}$GeV$^{-1}$.

We construct the $\Sigma$-type currents to investigate the D-wave charmed baryon states with the QCD sum rules systematically. The predicted masses $M=3.35^{+0.13}_{-0.18}\,\rm{GeV}$ ($3.33^{+0.13}_{-0.16}\,\rm{GeV}$), $3.34^{+0.14}_{-0.18}\,\rm{GeV}$ ($3.35^{+0.13}_{-0.16}\,\rm{GeV}$) and $3.35^{+0.12}_{-0.13}\,\rm{GeV}$ ($3.35^{+0.12}_{-0.14}\,\rm{GeV}$) for the $\Omega_c(0,2,{\frac{1}{2}}^+)$, $\Omega_c(0,2,{\frac{3}{2}}^+)$ and $\Omega_c(0,2,{\frac{5}{2}}^+)$ states are in excellent agreement with the experimental data $ 3327.1\pm1.2 \mbox{ MeV}$ from the LHCb collaboration, and support assigning the $\Omega_c(3327)$ to be the $\Sigma$-type D-wave $\Omega_c$ state with the spin-parity $J^P={\frac{1}{2}}^+$, ${\frac{3}{2}}^+$ or ${\frac{5}{2}}^+$., Comment: 26 pages, 13 figures

Motivated by recent progresses in experiments in searching for the $\Omega_{c}$ baryons, we systematically analyze the strong decay behaviors of single heavy baryons $\Lambda_{Q}$, $\Sigma_{Q}$ and $\Omega_{Q}$. The two-body strong decay properties of $S$-wave, $P$-wave and some $D$-wave states are studied with the $^{3}P_{0}$ model. The results support assigning the recently observed $\Omega_{c}(3185)$ and $\Omega_{c}(3327)$ as the 2S($\frac{3}{2}^{+}$) and 1D($\frac{3}{2}^{+}$) states, respectively. In addition, the quantum numbers of many other experimentally observed baryons are also suggested according to their strong decays. Finally, some baryons which have good potentials to be observed in experiments are predicted and the possible decay channels for searching for these predicted states are also suggested., Comment: arXiv admin note: substantial text overlap with arXiv:2206.08128

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., Comment: 20 pages, 7 figures

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., Comment: to be published in European Physical Journal C

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 $\rho$-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 $\Xi_{bc}^{'}$ ($\Xi_{bc}$) and $\Omega_{bc}^{'}$ ($\Omega_{bc}$) 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., Comment: 19 pages, 9 figures, 6 tables. arXiv admin note: text overlap with arXiv:2210.13085

In this paper, we apply the QCD sum rules to study the vector fully-light tetraquark states with an explicit P-wave between the diquark and antidiquark pair. We observed that the $C\gamma_\alpha\otimes\stackrel{\leftrightarrow}{\partial}_\mu\otimes\gamma^\alpha C$ (or $C\gamma_\alpha\otimes\stackrel{\leftrightarrow}D_\mu\otimes\gamma^\alpha C$) type current with fully-strange quarks couples potentially to a tetraquark state with the mass $2.16 \pm 0.14 \,\rm{GeV}$, which supports assigning the $Y/\phi(2175)$ as the diquark-antidiquark type tetraquark state with the $J^{PC}=1^{--}$. The $qs\bar{q}\bar{s}$ and $ss\bar{s}\bar{s}$ vector tetraquark states with the structure $C\gamma_\mu\otimes \stackrel{\leftrightarrow}{\partial}_\alpha \otimes\gamma^\alpha C + C\gamma^\alpha \otimes\stackrel{\leftrightarrow}{\partial}_\alpha \otimes\gamma_\mu$ (or $C\gamma_\mu\otimes \stackrel{\leftrightarrow}D_\alpha \otimes\gamma^\alpha C + C\gamma^\alpha \otimes\stackrel{\leftrightarrow}D_\alpha \otimes\gamma_\mu$) are consistent with the $X(2200)$ and $X(2400)$ respectively, which lie in the region $2.20$ to $2.40\,\rm{GeV}$. The central values of the masses of the fully-strange vector tetraquark states with an explicit P-wave are about $2.16-3.13\,\rm{GeV}$ (or $2.16-3.16\,\rm{GeV}$), and the predictions for other fully-light vector tetraquark states with and without hidden-strange are also presented., Comment: 20 pages, 17 figures

Stimulated by the recent experimental progress on the $T_{\psi\psi}$ 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 $T_{\psi\psi}(6200)$, $T_{\psi\psi}(6600)$, $T_{\psi\psi}(6900)$, and $T_{\psi\psi}(7300)$ 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 $T_{\psi\psi}$ states, there are uncertainties about the assignments of the $T_{\psi\psi}(6600)$, $T_{\psi\psi}(6900)$, and $T_{\psi\psi}(7300)$ 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., Comment: 18 pages

In this work, we perform a systematic study of the mass spectra, the root mean square(r.m.s.) radii and the radial density distributions of the doubly charmed baryons $\Xi_{cc}$ and $\Omega_{cc}$. The calculations are carried out in the frame work of Godfrey-Isgur (GI) relativized quark model, where the baryon is regarded as a real three-body system of quarks. Our results show that the excited energy of doubly charmed baryon with $\rho$-mode is lower than those of the $\lambda$-mode and $\lambda$-$\rho$ mixing mode, which indicates that the lowest state is dominated by the $\rho$-mode. According to this conclusion, we systematically investigate the mass spectra, the r.m.s. radii of the ground and excited states($1S\sim4S$, $1P\sim4P$, $1D\sim4D$, $1F\sim4F$ and $1G\sim4G$) with $\rho$-mode. Using the wave functions obtained from quark model, we also study the radial density distributions. Finally, with the predicated mass spectra, the Regge trajectories of $\Xi_{cc}$ and $\Omega_{cc}$ in the ($J$,$M^{2}$) plane are constructed, and the slopes, intercepts are determined by linear fitting. It is found that model predicted masses fit nicely to the constructed Regge trajectories.

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 $\rho$-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 $\Xi_{bb}$ and $\Omega_{bb}$ 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., Comment: 16 pages, 9 figures, 5 tables. arXiv admin note: text overlap with arXiv:2207.04167

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., Comment: 9 pages, 8 figures

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 $1^{+-}$., Comment: 14 pages, 2 figures. arXiv admin note: text overlap with arXiv:2006.13028

In this work, we tentatively identify the $P_{cs}(4338)$ as the $\bar{D}\Xi_c$ molecular state, and distinguish the isospins of the current operators to explore the $\bar{D}\Xi_c$, $\bar{D}\Lambda_c$, $\bar{D}_s\Xi_c$, $\bar{D}_s\Lambda_c$, $\bar{D}^*\Xi_c$, $\bar{D}^*\Lambda_c$, $\bar{D}^*_s\Xi_c$ and $\bar{D}^*_s\Lambda_c$ 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 $\bar{D}\Xi_c$ ($\bar{D}^*\Xi_c$) 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 $J/\psi\Sigma^0/\eta_c\Sigma^0$ invariant mass distributions would decipher their inner structures., Comment: 20 pages, 5 figures

Motivated by the experimental progress in the study of heavy baryons, we investigate the mass spectra of strange single heavy baryons in the $\lambda$-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 $\Xi_{c}(3055)$, $\Xi_{c}(3080)$, $\Xi_{c}(2930)$, $\Xi_{c}(2923)$, $\Xi_{c}(2939)$, $\Xi_{c}(2965)$, $\Xi_{c}(2970)$, $\Xi_{c}(3123)$, $\Xi_{b}(6100)$, $\Xi_{b}(6227)$, $\Xi_{b}(6327)$ and $\Xi_{b}(6333)$. 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., Comment: 27 pages, 11 figures, 8 tables

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., Comment: 14 pages, 4 figures

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 $\Lambda_{Q}$, $\Sigma_{Q}$ and $\Omega_{Q}$. 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 $\lambda$-mode is lower than those of the $\rho$-mode and $\lambda$-$\rho$ mixing mode, which indicates that the lowest state is dominated by the $\lambda$-mode. Basing on this research, we systematically calculate the mass spectra and the root mean square radius of the baryons with $\lambda$ 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., Comment: to be published in Nuclear Physics B

In this work, we explore the hadronic coupling constants $G_{ZJ/\psi K}$, $G_{Z\eta_c K^*}$, $G_{ZD^* \bar{D}_s}$ 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 $\Gamma_{Z_{cs}}^T =15.31\pm 2.06\,\rm{MeV}$ and $\Gamma_{Z_{cs}}^M=83.51\pm21.09\,\rm{MeV}$, 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., Comment: 13 pages, 2 figures