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S. S. Agaev

Publications and source records attributed to S. S. Agaev.

At least 19 recordsLinked to original sources
arXiv2026

Resonance $X(6600)$

The resonance $X(6600)$ is explored as the all-charm tetraquark structure with spin-parities $J^{\mathrm{PC}}=2^{++}$. It is considered in the diquark-antidiquark picture and modeled as a tensor state $X$ composed of the axial-vector diquark $cCγ_μc$ and antidiquark $\overline{c}% γ_νC\overline{c}$ with $C$ being the charge conjugation matrix. The mass and decay width of $X$ are evaluated in the framework of QCD sum rule (SR) methods. The two-point SR approach is applied to find its spectroscopic parameters, while three-point SRs used to calculate partial widths of different decay channels of $X$. We study its leading decays $X \to J/ψJ/ψ$, $X \to η_{c}η_{c}$ and $χ_{c1}(1P)η_{c}$ in which all four $c$-quarks constitute final-state mesons. We consider also the subleading channels $X\to D_{(s)}^{(\ast )+}D_{(s)}^{(\ast )-}$ and $% D_{(s)}^{(\ast )0}\overline{D}_{(s)}^{(\ast )0}$ generated by annihilation of $\overline{c}c$ quarks in the tetraquark. Comparison of the mass $m=(6609 \pm 50)~ \mathrm{MeV}$ and width $Γ[X]=(165 \pm 23)~ \mathrm{MeV}$ of the tensor diquark-antidiquark state $X$ with experimental data allows us to interpret it as an essential component of the resonance $X(6600)$. We also provide a lower limit for the mass of the first radial excitation of $X$.

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arXiv2026

Tensor states $ΥB_{c}^{\ast -}$ and $J/ψB_{c}^{\ast +}$

Tensor states $\mathcal{M}_{\mathrm{T}}^{\mathrm{b}}=ΥB_{c}^{\ast -}$ and $\mathcal{M}_{\mathrm{T}}^{\mathrm{c}}=J/ψB_{c}^{\ast +}$ are explored using techniques of QCD sum rule method. These hadronic molecules, composed of only heavy quarks, have asymmetric quark contents $bb\overline{b} \overline{c}$ and $cc\overline{c}\overline{b}$, respectively. The masses $ m=(15864 \pm 85)~\mathrm{MeV}$ and $\widetilde{m}=(9870 \pm 82)~\mathrm{MeV} $ prove that these structures are unstable against dissociations to constituent mesons. Full widths of molecules $\mathcal{M}_{\mathrm{T}}^{ \mathrm{b}}$ and $\mathcal{M}_{\mathrm{T}}^{\mathrm{c}}$ are calculated by considering their dominant and subleading decay channels. The subleading channels are processes generated by annihilations of $\overline{b}b$ and $ \overline{c}c$ quarks. For the molecule $\mathcal{M}_{\mathrm{T}}^{\mathrm{b} }$ dominant decays are $\mathcal{M}_{\mathrm{T}}^{\mathrm{b}} \to ΥB_{c}^{\ast -}$ and $\mathcal{M}_{\mathrm{T}}^{\mathrm{b}} \to η_b B_{c}^{-}$, whereas subleading channels are transformations to $\mathcal{M} _{ \mathrm{T}}^{\mathrm{b}}\rightarrow B^{(\ast )-}\overline{D}^{(\ast )0}$ and $\overline{B}_{(s)}^{(\ast )0}D_{(s)}^{(\ast )-}$ mesons. In the lower limit ($\mathrm{l.l.}$) of the mass $m=15779~\mathrm{MeV}$ for $\mathcal{M}_{ \mathrm{T}}^{\mathrm{b}}$ decay to $ΥB_{c}^{\ast -}$ mesons is forbidden. In the case of $\mathcal{M}_{\mathrm{T}}^{\mathrm{c}}$ we explore decays to $J/ψB_{c}^{\ast +}$, $η_{c}B_{c}^{+}$, $B^{(\ast)+}D^{(\ast )0}$ and $B_{(s)}^{(\ast )0}D_{(s)}^{(\ast )+}$ mesons. Predictions $Γ[ \mathcal{M} _{\mathrm{T}}^{\mathrm{b}}]=120^{+17}_{-12}~ \mathrm{MeV}$, $ Γ[\mathcal{M}_{\mathrm{T}}^{\mathrm{b}}]_{\mathrm{l.l.}}=(65 \pm 7)~ \mathrm{MeV}$ and ...

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arXiv2026

Tensor molecule $J/ψJ/ψ$: A candidate to the resonance $X(6200) $

The hadronic tensor molecule $\mathcal{M}=J/ψJ/ψ$ is investigated in the framework of QCD sum rule method. We evaluate its mass and current coupling using the two-point SR approach. Our result $m=(6290 \pm 50)~ \mathrm{MeV}$ for the mass of $\mathcal{M}$ indicates that it can decay to a pair of mesons $J/ψJ/ψ$. Apart from this dominant channel there are subdominant modes of the molecule $\mathcal{M}$ generated due to annihilation of constituent $\overline{c}c$ quarks to pairs of light quarks $ \overline{q}q$ and $\overline{s}s$. This mechanism launches processes $ \mathcal{M} \to D_{(s)}^{(\ast )+}D_{(s)}^{(\ast )-}$, $DD_{1}(2420)$, $ D_sD_{s1}(2460)$ and $D_{(s)}^{(\ast )0}\overline{D}_{(s)}^{(\ast )0}$. The decays of $\mathcal{M}$ are explored by applying technical tools of the three-point sum rule approach which is necessary to estimate strong couplings at $\mathcal{M}$-meson-meson vertices. Comparing the mass $m$ of the molecule $\mathcal{M}$ and its decay width $Γ[\mathcal{M}]=(149 \pm 21)~ \mathrm{MeV}$ with available experimental data, we discuss the molecule $\mathcal{M}$ as a possible candidate to the tensor resonance $X(6200)$.

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arXiv2026

Fully-beauty tensor tetraquark

Parameters of the fully-beauty tensor tetraquark $ T=bb\overline{b}\overline{b}$ are computed using QCD sum rule method. The mass $m$ and coupling $Λ$ of this state are evaluated by means of two-point sum rule approach. Prediction $m=(18530 \pm 86)~\mathrm{MeV}$ for the mass demonstrates that $T$ is stable against decays to pairs of $η_b η_b$ and $ΥΥ$ mesons. But it transforms to conventional particles due to $\overline{b}b$ annihilations to light quarks $\overline{q} q $ and $\overline{s}s$ followed by creation of mesons $B^{(\ast)+}B^{( \ast)-}$, $B^{(\ast)0}\overline{B}^{(\ast)0}$ and $B_s^{(\ast)0}\overline{B} _s^{(\ast)0}$. Partial width of these decay channels are calculated by invoking technical tools of three-point sum rule method. The latter allows us to estimate strong couplings at relevant tetraquark-meson-meson vertices and, hence, a width of the process under consideration. Our prediction $ Γ=(48 \pm 6)~\mathrm{MeV}$ along with the mass of this state can be valuable for experimental studies of all-heavy resonances.

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arXiv2026

Scalar molecules $η_{b}B_{c}^{-}$ and $η_{c}B_{c}^{+} $ with asymmetric quark contents

The hadronic scalar molecules $\mathcal{M}_{b}$ and $\mathcal{M}_{c}$ with asymmetric quark contents $bb \overline{b}\overline{c}$ and $cc \overline{c} \overline{b}$ are explored by means of the QCD sum rule method. Their masses and current couplings are calculated using the two-point sum rule approach. The obtained results show that they are strong-interaction unstable particles and transform to ordinary mesons' pairs. The molecule $\mathcal{M} _{b}$ dissociates through the process $\mathcal{M}_{\mathrm{b}}\to η_{b}B_{c}^{-}$. The decays $\mathcal{M}_{\mathrm{c}}\rightarrow η_{c}B_{c}^{+}$ and $J/ψB_{c}^{\ast +}$ are dominant modes for the molecule $\mathcal{M}_{c}$. The full decay widths of the molecules $\mathcal{ \ \ M}_{b}$ and $\mathcal{M}_{c}$ are estimated using these decay channels, as well as ones generated by the annihilation of $b\overline{b}$ and $c \overline{c}$ quarks in $\mathcal{M}_{b}$ and $\mathcal{M}_{c}$, respectively. The QCD three-point sum rule method is employed to find partial widths all of these channels. This approach is required to evaluate the strong couplings at the molecule-meson-meson vertices under consideration. The mass $m=(15728 \pm 90)~\mathrm{MeV}$ and width $Γ[ \mathcal{M}_b] =(93 \pm 17)~ \mathrm{MeV}$ of the molecule $\mathcal{M}_{b}$ , and $\widetilde{m}=(9712 \pm 72)~\mathrm{MeV}$ and $Γ[\mathcal{M}_c] =(70 \pm 10)~ \mathrm{MeV}$ in the case of $\mathcal{M}_{c} $ offer valuable guidance for experimental searches at existing facilities.

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arXiv2026

Molecular states $J/ψB_{c}^{+}$ and $η_{c}B_{c}^{\ast +} $

Hadronic molecules $\mathfrak{M}=J/ψB_{c}^{+}$ and $\widetilde{\mathfrak{ \ M}}=η_{c}B_{c}^{\ast +}$ are investigated in the framework of QCD sum rule method. These particles with spin-parities $J^{\mathrm{P}}=1^+$ have the quark contents $cc \overline{c}\overline{b}$. We compute their masses and current couplings and find that they are numerically very close to each other coinciding within accuracy of the sum rule method. Therefore, we concentrate on the molecule $J/ψB_{c}^{+}$ and explore features of this state in a detailed form. Our prediction $m=(9740 \pm 70)~\mathrm{MeV}$ for its mass means that $\mathfrak{M}$ easily decays to pairs of ordinary mesons through strong interactions. There are two mechanisms responsible for transformations of $\mathfrak{M}$ to conventional mesons. The fall-apart mechanism generates the dominant decay channels $\mathfrak{M} \to J/ψB_{c}^{+}$ and $\mathfrak{M} \to η_{c}B_{c}^{\ast +}$. Annihilation of $ \overline{c}c$ quarks triggers subdominant processes with various final-state $B$ and $D$ mesons: Six of such channels are considered in this work. The partial widths all of decays are computed using the three-point sum rule approach. The width $Γ[ \mathfrak{M}]=(121 \pm 17)~ \mathrm{MeV }$ of the hadronic axial-vector molecule $\mathfrak{M}$, as well as its mass provide valuable information for running and future experiments.

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arXiv2026

Axial-vector molecules $ΥB_{c}^{-}$ and $η_{b}B_{c}^{\ast-} $

Axial-vector hadronic molecules $\mathcal{M}_{\mathrm{AV}}=ΥB_{c}^{-} $ and $\widetilde{\mathcal{M}}_{\mathrm{AV}}=η_{b}B_{c}^{\ast -} $ with the quark content $bb \overline{b}\overline{c}$ are studied using QCD sum rule method. The spectroscopic parameters of these molecules are computed in the context of the two-point sum rule method. Predictions for their masses are identical to each other and confirm that they are structures unstable against dissociations to ordinary heavy mesons. We evaluate the width of the state $\mathcal{M}_{\mathrm{AV}}$ and assume that it is equal to that of $\widetilde{\mathcal{M}}_{\mathrm{AV}} $. To this end, we explore its dominant decay channels $\mathcal{M}_{\mathrm{AV}} \to ΥB_{c}^{-} $ and $\mathcal{M}_{\mathrm{AV}} \to η_{b}B_{c}^{\ast -}$. There also are subleading modes of $\mathcal{M}_{\mathrm{AV}}$ generated due to annihilation of $\overline{b}b$ quarks. We consider decays of the molecule $\mathcal{M}_{\mathrm{AV}}$ to pairs of the mesons $B^{\ast -} \overline{D}^{0}$, $\overline{B}^{\ast 0} D^{-}$, $B^{-} \overline{D} ^{\ast 0}$, $\overline{B}^{0} D^{\ast -}$, $\overline{B}_{s}^{\ast 0} D_{s}^{-}$, and $\overline{B}_{s}^{0} D_{s}^{\ast -}$. To find strong couplings at the $\mathcal{M}_{\mathrm{AV}}$-meson-meson vertices which determine the partial widths of these processes, we apply QCD three-point sum rule approach. The mass $m=(15800 \pm 90)~\mathrm{MeV}$ and width $ Γ[\mathcal{M}_{\mathrm{AV}}]=(114 \pm 17)~ \mathrm{MeV}$ of the molecule $\mathcal{M}_{\mathrm{AV}}$ are useful for experimental studies of fully heavy molecular structures at ongoing and planning experiments.

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arXiv2025

Hadronic tensor molecule $B_c^{\ast +}B_c^{\ast -}$

Mass and full decay width of the hadronic tensor molecule $\mathcal{M}_{ \mathrm{T}}=B_c^{\ast +}B_c^{\ast -}$ are examined in the framework of QCD sum rule method. To find the mass $m$ and current coupling $Λ$ of this state, we use the two-point sum rules. The result $(12.87 \pm 0.08)~\mathrm{ GeV}$ for $m$ indicates that $\mathcal{M}_{\mathrm{T}}$ can easily decay to pairs of $J/ψΥ$, $η_{b}η_{c}$, $B_{c}^{+}B_{c}^{-}$, and $ B_{c}^{\ast +}B_{c}^{\ast -}$ mesons. Kinematically permitted ways for $ \mathcal{M}_{\mathrm{T}}$ to transform to conventional mesons include also processes $\mathcal{M}_{\mathrm{T}} \to D^{(\ast)+}D^{(\ast )-}$, $D^{(\ast )0}\overline{D}^{(\ast )0}$, and $D_{s}^{(\ast)+}D_{s}^{(\ast)-}$ triggered by annihilation of $b\overline{b}$ quarks in the molecule. The decays to meson pairs $B^{(\ast)+}B^{(\ast )-}$, $B^{(\ast )0}\overline{B}^{(\ast )0}$ , and $B_{s}^{(\ast)0}\overline{B}_{s}^{(\ast )0}$ generated by $c\overline{c } \to $ light quarks are also among possible channels of the hadronic molecule $\mathcal{M}_{\mathrm{T}}$. Technical tools of the three-point sum rule approach are applied to compute partial widths of these decays. Our results for the mass and width $Γ_{\mathcal{M}_{\mathrm{T}}}=(154 \pm 19)~ \mathrm{MeV} $ of the tensor molecule $\mathcal{M}_{\mathrm{T}}$ are important for experimental studies of fully heavy exotic structures.

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arXiv2025

Axial-vector molecular structures $B_{c}^{\ast \pm} B_{c}^{\mp}$

The axial-vector molecular structure $\mathcal{M}_{\mathrm{AV}}=(B_{c}^{\ast +}B_{c}^{-} + B_{c}^{\ast - } B_{c}^{+})/2$ is explored in QCD sum rule framework. The mass and current coupling of this compound are found by means of the two-point sum rule method. It turns out that the mass of $\mathcal{M} _{\mathrm{AV}}$ is equal to $m=(12770 \pm 60)~\mathrm{MeV}$ making possible its dissociations to pairs of $J/ψη_b$, $Υη_c$, $ B_{c}^{\ast +} B_{c}^{-}$, and $B_{c}^{\ast - } B_{c}^{+}$ mesons. The partial widths of these decay modes contain the strong couplings at $ \mathcal{M}_{\mathrm{AV}}$-meson-meson vertices which are calculated by utilizing the three-point sum rule method. The full decay width of the molecule $\mathcal{M}_{\mathrm{AV}}$ is formed due to these dominant processes and amounts to $Γ[\mathcal{M}_{\mathrm{AV}}]=(93 \pm 14)~ \mathrm{MeV}$. Our results for parameters $m$ and $Γ[\mathcal{M}_{ \mathrm{AV}}]$ of the hadronic molecule $\mathcal{M}_{\mathrm{AV}}$ are useful for experimental studies of various fully heavy four-quark mesons.

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arXiv2025

Heavy scalar molecule $B_{c}^{+} B_{c}^{-}$

Mass and full width of the heavy scalar molecule $\mathcal{M}$ composed of the mesons $B_{c}^{+}$ and $B_{c}^{-}$ are calculated in the QCD sum rule framework. To find its mass and current coupling, we apply the two-point sum rule method. The width of the hadronic molecule $\mathcal{M} =B_{c}^{+}B_{c}^{-}$ is evaluated by taking into account its dissociation to $η_cη_{b}, J/ψΥ$, and $B_{c}^{+}B_{c}^{-} $ mesons. Decays into $D$ and $B$ meson pairs with appropriate charges and quantum numbers triggered by $\overline{b}b$ and $\overline{c}c$ annihilations to light quark-antiquarks are also included in the analyses. Because the partial widths of $\mathcal{M}$ molecule's decay channels depend on the strong couplings at $\mathcal{M}$-meson-meson vertices, we estimate them by invoking tools of the three-point sum rule method. Our predictions $m=(12725 \pm 85)~\mathrm{ MeV}$ and $Γ[\mathcal{\ M}]=(155 \pm 23)~ \mathrm{MeV}$ for the parameters of the molecule $\mathcal{\ M}$ provide useful information for experimental studies of numerous heavy resonances.

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arXiv2025

Tensor hybrid charmonia

The mass and current coupling of the tensor hybrid charmonia $H_{\mathrm{c}} $ and $\widetilde{H}_{\mathrm{c}}$ with quantum numbers $J^{\mathrm{PC} }=2^{-+}$ and $2^{++}$, as well as their full widths are calculated in the context of the QCD sum rule method. The spectral parameters of these states are computed using the QCD two-point sum rule approach including dimension-12 terms $ \sim \langle g_{s}^{3}G^{3}\rangle ^{2} $. The full decay widths of the charmonia $H_{\mathrm{c}}$ and $\widetilde{H}_{\mathrm{c}}$ are evaluated by considering their kinematically allowed decay channels. In the case of the hybrid state $H_{\mathrm{c}} $ decays to $D^{(\pm )}D^{\ast (\mp )}$, $D^{0} \overline{D}^{\ast 0}$, and $D_{s}^{(\pm )}D_{s}^{\ast (\mp )} $ mesons are taken into account. The processes $\widetilde{H}_{\mathrm{c}} \to D^{(\ast)+}D^{(\ast )-}$, $D^{(\ast) 0}\overline{D}^{(\ast) 0}$, and $ D_{s}^{(\ast)+}D_{s}^{(\ast) -} $ are employed to estimate the full width of the hybrid charmonium $\widetilde{H}_{\mathrm{c}}$. The partial widths of these decays are computed by means of the QCD three-point sum rule method which is necessary to calculate strong couplings at the relevant hybrid-meson-meson vertices. Our predictions $m=(4.16\pm 0.14)~\mathrm{GeV}$ , and $\widetilde{m}=(4.5\pm 0.1)~\mathrm{GeV}$ for the masses and $Γ\left[ H_{\mathrm{c}}\right] =(160\pm 30)~\mathrm{MeV}$, and $Γ\left[ \widetilde{H }_{\mathrm{c}}\right] =(206\pm 33)~\mathrm{MeV}$ for the full width of these hybrid charmonia can be useful to study and interpret various resonances in the $4-5~\mathrm{GeV}$ mass range.

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arXiv2025

Fully heavy asymmetric scalar tetraquarks

The scalar tetraquarks $T_{b}$ and $T_{c}$ with asymmetric contents $bb \overline{b}\overline{c}$ and $cc \overline{c}\overline{b}$ are explored using the QCD sum rule method. These states are modeled as the diquark-antidiquarks composed of the axial-vector components. The masses and current couplings of $T_{b}$ and $T_{c}$ are calculated using the two-point sum rule approach. The predictions obtained for the masses of these four-quark mesons prove that they are unstable against the strong two-meson fall-apart decays to conventional mesons. In the case of the tetraquark $ T_{b}$ this is the decay $T_{\mathrm{b}}\to η_{b}B_{c}^{-}$. The processes $T_{\mathrm{c}}\rightarrow η_{c}B_{c}^{+}$ and $J/ψB_{c}^{\ast +}$ are kinematically allowed decay modes of the tetraquark $ T_{c}$. The widths of corresponding processes are evaluated by employing the QCD three-point sum rule approach which are necessary to estimate strong couplings at the tetraquark-meson-meson vertices of interest. The mass $ m=(15698 \pm 95)~\mathrm{MeV}$ and width $Γ[T_b]=(36.0 \pm 10.4)~ \mathrm{MeV}$ of the tetraquark $T_{b}$ as well as the parameters $ \widetilde{m}=(9680 \pm 102)~\mathrm{MeV}$ and $Γ[T_c]=(54.7 \pm 12.6)~ \mathrm{MeV}$ in the case of $T_{c}$ provide useful information to search for and interpret new exotic states.

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arXiv2025

Tensor hybrid mesons $\overline{b}gc$

Spectroscopic parameters and widths of the tensor hybrid mesons $H_{\mathrm{ bc}}$ and $\widetilde{H}_{\mathrm{bc}}$ with the structure $\overline{b}gc$ and spin-parities $J^{\mathrm{P}}=2^{-}$ and $J^{\mathrm{P}}=2^{+}$ are calculated with high accuracy in the QCD sum rule framework. Information on their masses $m=(7.214\pm 0.075)~\mathrm{GeV}$ and $\widetilde{m} =(7.685\pm 0.040)~\mathrm{GeV}$ enable us to determine decay channels of $H_{\mathrm{bc} }$ and $\widetilde{H}_{\mathrm{bc}}$. The full width of the meson $H_{ \mathrm{bc}}$ is estimated by considering the decays $H_{\mathrm{bc}} \to D^{+}\overline{B}^{\ast 0}$ and $D^{0}B^{\ast +}$. The channels $\widetilde{H }_{\mathrm{bc}}\to B^{+}D^{0}$, $B^{0}D^{+}$, $B^{\ast +}D^{\ast 0}$, $ B^{\ast 0}D^{\ast +} $, $B_{s}^{0}D_{s}^{+}$, and $B_{s}^{\ast 0}D_{s}^{\ast +}$ are studied to find the width of the $\widetilde{H}_{\mathrm{bc}}$ state. The widths of these processes are calculated using QCD three-point sum rule approach, which require estimation of the strong couplings at hybrid-meson-meson vertices. The results $(50.8 \pm 9.8)~\mathrm{MeV}$ and $ (184.3\pm 22.8)~\mathrm{MeV}$ for the full widths of the hybrid mesons $H_{ \mathrm{bc}}$ and $\widetilde{H}_{\mathrm{bc}}$ characterize them as relatively narrow and broad structures, respectively.

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arXiv2025

Properties of the tensor state $bc\overline{b}\overline{c}$

Spectroscopic parameters and decays of the exotic tensor meson $T$ with content $bc \overline{b}\overline{c}$ are explored in the context of the diquark-antidiquark model. We treat it as a state built of axial-vector diquark $b^{T}Cγ_{μ}c$ and antidiquark $\overline{b}γ_{ν}C \overline{c}^{T}$, where $C$ is the charge conjugation matrix. The mass $m$ and current coupling $Λ$ of this tetraquark are extracted from two-point sum rules. Our result for $m=(12.70 \pm 0.09)~\mathrm{GeV}$ proves that $T$ is unstable against strong dissociations to two-meson final states. Its dominant decay channels are processes $T \to J/ψΥ$, $ η_{b}η_{c}$, and $B_{c}^{(\ast) +}B_{c}^{(\ast) -}$. Kinematically allowed transformations of $T$ include also decays $T\rightarrow D^{(\ast )+}D^{(\ast )-}$ and $D^{(\ast )0}\overline{D}^{(\ast )0}$, which are generated by $b\overline{b}$ annihilation inside of $T$. The full width of $ T $ is estimated by considering all of these channels. Their partial widths are calculated by invoking methods of three-point sum rule approach which are required to evaluate strong couplings at corresponding tetraquark-meson-meson vertices. Our predictions for the mass and width $ Γ_{T}=(117.4 \pm 15.9)~ \mathrm{MeV} $ of the tensor state $T$ provide useful information for experimental studies of fully heavy four-quark exotic structures.

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arXiv2025

Pseudoscalar and vector tetraquarks $bb\overline{c}\overline{c}$

The pseudoscalar and vector four-quark states $bb\overline{c}\overline{c}$ are studied in the context of the QCD sum rule method. We model $T_{\mathrm{ \ \ PS}} $ and $T_{\mathrm{V}}$ as structures built of diquarks $ b^{T}Cγ_{5}b$, $\overline{c}C\overline{c}^{T}$ and $b^{T}Cγ_{5}b$ , $\overline{c}Cγ_μγ_{5}\overline{c}^{T}$, respectively, with $ C$ being the charge conjugation matrix. The spectroscopic parameters of the tetraquarks $T_{\mathrm{PS}}$ and $T_{\mathrm{V}}$, i.e., their masses and current couplings are calculated using QCD two-point sum rule method. We evaluate the full widths of $T_{\mathrm{PS}}$ and $T_{\mathrm{V}}$ by taking into account their kinematically allowed decay channels. In the case of the pseudoscalar particle they are processes $T_{\mathrm{PS}} \to B_{c}^{-}B_{c}^{\ast -}$, $B_{c}^{-}B_{c}^{-}(1^{3}P_{0})$ and $B_{c}^{\ast -}B_{c}^{-}(1^{1}P_{1})$. The vector state $T_{\mathrm{V}}$ can dissociate to meson pairs $2 B_{c}^{-}$, $2 B_{c}^{\ast -}$ and $ B_{c}^{-}B_{c}^{-}(1^{1}P_{1})$. Partial widths of these decays are determined by the strong couplings at relevant tetraquark-meson-meson vertices, which evaluated in the context of the three-point sum rule approach. Predictions obtained for the mass and full width of the pseudoscalar $m =(13.092\pm 0.095)~\mathrm{GeV}$, $Γ_{\mathrm{PS} }=(63.7\pm 13.0)~\mathrm{MeV}$ and vector $\widetilde{m} =(13.15\pm 0.10)~ \mathrm{GeV}$, $Γ_{\mathrm{V}}=(53.5\pm 10.3)~\mathrm{MeV}$ tetraquarks can be useful for analyses of different four-quark resonances.

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arXiv2025

Hidden charm-bottom structures $bc\overline{b}\overline{c}$: Axial-vector case

Mass and width of a hidden charm-bottom axial-vector structure $T$ containing $bc \overline{b}\overline{c}$ quarks are calculated in QCD sum rule framework. It is treated as a diquark-antidiquark state built of scalar diquark and axial-vector antidiquark components. The mass of $T$ is computed using the two-point sum rule method. The width of this particle is evaluated by considering eight decay modes: The decays to $η_{b}J/ψ$, $η_{c}Υ(1S)$, $B_{c}^{-}B_{c}^{\ast +}$, and $B_{c}^{+}B_{c}^{\ast -}$ are dissociation processes, in which all initial quarks are distributed between the final-state particles. The decays to $DD$ and $BB$ mesons with appropriate charges and spin-parities are channels generated due to the annihilations of $b\overline{b}$ and $c\overline{c}$ quarks from $T$. Partial widths for all of these processes are obtained by employing the three-point sum rule approach necessary to find the strong couplings at relevant tetraquark-meson-meson vertices. Our results for the mass $ m=(12715\pm 90)~\mathrm{MeV}$ and width $Γ[T] =(140 \pm 13)~ \mathrm{MeV }$ of the tetraquark $T$, as well as its numerous decay channels explored in this article are useful for ongoing and future experimental investigations of fully heavy resonances.

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arXiv2024

Heavy four-quark mesons $bc\overline{b}\overline{c}$: Scalar particle

Parameters of the heavy four-quark scalar meson $T_{\mathrm{bc\overline{b} \overline{c}}}$ with content $bc \overline{b}\overline{c}$ are calculated by means of the sum rule method. This structure is considered as a diquark-antidiquark state built of scalar diquark and antidiquark components. The mass and current coupling of $T_{\mathrm{bc\overline{b} \overline{c}}}$ are evaluated in the context of the two-point sum rule approach. The full width of this tetraquark is estimated by taking into account two types of its possible strong decay channels. First class includes dissociation of $T_{\mathrm{bc\overline{b}\overline{c}}} $ to mesons $η_cη_{b}$, $B_{c}^{+}B_{c}^{-}$, $B_{c}^{\ast +}B_{c}^{\ast -}$ and $B_{c}^{+}(1^3P_{0})B_{c}^{\ast-}$. Another type of processes are generated by annihilations $\overline{b}b \to \overline{q}q$ of constituent $ b$-quarks which produces the final-state charmed meson pairs $D^{+}D^{-}$, $ D^{0} \overline{D}^{0}$, $D^{*+}D^{*-}$, and $D^{*0}\overline{D}^{*0}$. Partial width all of these decays are found using the three-point sum rule method which is required to calculate strong couplings at corresponding meson-meson-tetraquark vertices. Predictions obtained for the mass $m=(12697 \pm 90)~\mathrm{MeV}$ and width $Γ[T_{\mathrm{bc\overline{b}\overline{c} }}]=(142.4 \pm 16.9)~ \mathrm{MeV}$ of this state are compared with alternative results, and are useful for further experimental investigations of fully heavy resonances.

hep-ph↗
arXiv2024

Parameters of the tensor tetraquark $bb\overline{c}\overline{c}$

The mass and width of the tensor tetraquark $T=bb\overline{c}\overline{c}$ with spin-parity $J^{\mathrm{P}}=2^{+}$ are calculated in the context of the QCD sum rule method. The tetraquark $T$ is modeled as a diquark-antidiquark state built of components $b^{T}Cγ_{μ}b$ and $\overline{c}γ_{ν}C\overline{c}^{T}$ with $C$ being the charge conjugation matrix. The mass $m=(12.795\pm 0.095)~\mathrm{GeV}$ of the exotic tensor meson $T$ is found by means of the two-point sum rule approach. Its full width $Γ$ is evaluated by considering processes $T \to B_{c}^{-}B_{c}^{-}$, $ B_{c}^{-}B_{c}^{\ast -}$, and $B_{c}^{\ast -}B_{c}^{\ast -}$. Partial widths of these decays are computed by means of the three-point sum rule approach which is used to determine the strong couplings at relevant tetraquark-meson-meson vertices. Predictions obtained for the width $Γ_{\mathrm{T}}=55.5_{-9.9}^{+10.6}~\mathrm{MeV}$, as well as the mass of the tetraquark $T $ can be useful in investigations of fully heavy four-quark mesons.

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