arXiv subjects

Zi-Yan Yang

Publications and source records attributed to Zi-Yan Yang.

9 recordsLinked to original sources

arXiv2025

Decay and production properties of strange double charm pentaquark

In this work we investigate the decay and production properties of the strange double-charm pentaquark $P_{ccs}^{++}$ with strangeness $S=-1$. Building upon our previous work predicting its $J^P=1/2^-$ molecular configuration, we employ three-point QCD sum rules to calculate its strong decay widths and estimate its production branching ratio via $\Xi_{bc}^+$ baryon decays. The total strong decay width to the $\Xi_{cc}\bar{K}$ and $\Omega_{cc}\pi$ final-state channels is determined as $85\pm19$ MeV. Furthermore, using a rescattering mechanism, we analyze the $\Xi_{bc}^+\rightarrow D_s^{\ast-}\Xi_{cc}^{++}\rightarrow D^-P_{ccs}^{++}$ process and estimate the production branching ratio to be $\mathcal{B}r(\Xi_{bc}^+\rightarrow D^-P_{ccs}^{++})=(4.3_{-1.5}^{+2.0})\times10^{-6}$. The relatively narrow width and detectable branching ratio suggest the possibility searching for this pentaquark state in the future.

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arXiv2025

Doubly charmed pentaquark states with strangeness $S=0, -1$

In this work, we have studied the mass spectra of doubly charmed pentaquark states with strangeness $S=0, -1$ by using the method of QCD sum rules. We use the parity projected sum rules to separate the contributions of negative and positive parities from the two-point correlation functions induced by the pentaquark interpolating currents. Our results predict the existence of some potential doubly charmed pentaquark bound states.

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arXiv2024

The production and decay of $X_0(2900)$ state with different interpretation

The observation of $X_0(2900)$ in $B^+\rightarrow D^+D^-K^+$ decay process indicates the existence of open flavor tetraquark states. We study the production and decay of $X_0(2900)$ state with final state interaction mechanism, where we calculate the strong vertices such as $g_{\bar{D}KX_0}$, $g_{\bar{D}^\ast K^\ast X_0}$, $g_{D_s^{\ast}\bar{D}K}$ and $g_{D_{s1}\bar{D} K^\ast}$ in the framework of QCD sum rules method. We find that for the interpretation of the $\bar{D}^\ast K^\ast$ molecule of $X_0(2900)$, the branching fraction of the production process and the decay width are consistent with the experimental results, indicating that the observed $X_0(2900)$ could be interpreted as the $\bar{D}^\ast K^\ast$ molecule. However, we cannot exclude the possibility of a compact tetraquark interpretation within the uncertainty. Further experimental and theoretical efforts should be made to fully understand the nature of the $X_0(2900)$ state.

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arXiv2024

Mass spectra of strange double charm pentaquarks with strangeness $S=-1$

The observation of the $T_{c\bar{s}}(2900)$ indicates the potential existence of strange double charm pentaquarks based on the heavy antidiquark symmetry. We systematically study the mass spectra of strange double charm pentaquarks with strangeness $S=-1$ in both molecular and compact structures for quantum numbers $J^{P}=1/2^{-}$, $3/2^{-}$, $5/2^{-}$. By constructing the interpolating currents, the mass spectra can be extracted from the two-point correlation functions in the framework of QCD sum rule method. In the molecular picture, we find that the $Ξ_c^+D^{\ast +}$, $Ξ_c^{'+}D^{\ast +}$, $Ξ_{c}^{\ast +}D^{\ast +}$, $Ξ_{cc}^{\ast ++}K^{\ast 0}$ and $Ω_{cc}^{\ast ++}ρ^0$ may form molecular strange double charm pentaquarks. In both pictures, the masses of the $J^P=1/2^-, 3/2^-$ pentaquarks locate within the $4.2-4.6~\mathrm{GeV}$ and $4.2-4.5~\mathrm{GeV}$ regions, respectively. As all of them are above the thresholds of their strong decay channels, they behave as a broad state, making them challenging to be detected in experiment. On the contrary, the mass of the $J^P=5/2^-$ strange double charm pentaquark is located at $4.3~\mathrm{GeV}$ and below its strong decay channel. This makes it as a narrow state and easy to be identified in experiment. The best observed channel is its semi-leptonic decay to double charm baryon. As the result, we strongly suggest experiments to search for $J^P=5/2^-$ strange double charm pentaquarks as a first try.

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arXiv2024

Doubly charmed pentaquark states in QCD sum rules

We have studied the mass spectra of doubly charmed pentaquark states in the $Λ_{c}^{(*)}D^{(*)}$ and $Σ_{c}^{(*)}D^{(*)}$ channels with $J^P=1/2^\pm$, $3/2^\pm$ and $5/2^\pm$ within the framework of QCD sum rules. We use the parity projected sum rules to separate the contributions of negative and positive parities from the two-point correlations induced by the pentaquark interpolating currents. Our results show that the bound states of $P_{cc}$ pentaquarks may exist in the $Λ_cD\, (\frac{1}{2}^-)$, $Σ_cD\, (\frac{1}{2}^-)$, $Σ_cD^*\, (\frac{3}{2}^-)$, $Λ_c^*D\, (\frac{3}{2}^-)$, $Λ_c^*D^*\, (\frac{5}{2}^-)$ channels with negative-parity and $Σ_cD\, (\frac{1}{2}^+)$, $Σ_cD^\ast\, (\frac{3}{2}^+)$, $Σ_c^\ast D\, (\frac{3}{2}^+)$ channels with positive-parity, since their masses are predicted to be lower than the corresponding meson-baryon thresholds. However, they are still allowed to decay into the $Ξ_{cc}^{(\ast)}π$ final states via strong interaction. The triply charged $P_{cc}^{+++}(ccuu\bar d)$ and neutral $P_{cc}^{0}(ccdd\bar u)$ in the isospin quartet would definitely be pentaquark states due to their exotic charges. We suggest searching for these characteristic doubly charmed pentaquark signals in the $P_{cc}^{+++}\toΞ_{cc}^{(\ast) ++}π^+/ρ^+$, $Σ_c^{(\ast)++}D^{(\ast)+}$ and $P_{cc}^{0}\toΞ_{cc}^{(\ast) +}π^-/ρ^-$, $Σ_c^{(\ast)0}D^{(\ast)0}$ decays in the near future.

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arXiv2023

$D$-wave excited $cs\bar{c}\bar{s}$ tetraquark states with $J^{PC}=1^{++}$ and $1^{+-}$

We study the mass spectra of D-wave excited $cs\bar{c}\bar{s}$ tetraquark states with $J^{PC}=1^{++}$ and $1^{+-}$ in both symmetric $\mathbf{6}_{cs}\otimes\bar{\mathbf{6}}_{\bar{c}\bar{s}}$ and antisymmetric $\bar{\mathbf{3}}_{cs}\otimes\mathbf{3}_{\bar{c}\bar{s}}$ color configurations by using the QCD sum rule method. We construct the D-wave diquark-antidiquark type of $cs\bar{c}\bar{s}$ tetraquark interpolating currents in various excitation structures with $(L_λ,L_ρ\{l_{ρ_1},l_{ρ_2}\})=(2,0\{0,0\}),(1,1\{1,0\}),(1,1\{0,1\}),(0,2\{1,1\}),(0,2\{2,0\}),(0,2\{0,2\})$. Our results support to interpret the recently observed $X(4685)$ resonance as a D-wave $cs\bar{c}\bar{s}$ tetraquark state with $J^{PC}=1^{++}$ in the $(2,0\{0,0\})$ or $(0,2\{2,0\})$ excitation mode, although some other possible excitation structures cannot be excluded exhaustively within theoretical errors. Moreover, our results provide a mass relation $6_{ρρ}<3_{λλ}<3_{λρ}<3_{ρρ}$ and $6_{ρρ}<3_{λλ}<6_{λλ}<3_{ρρ}$ for the positive and negative $\mathbb{C}$-parity D-wave $cs\bar{c}\bar{s}$ tetraquarks, respectively. We suggest searching for these possible D-wave $cs\bar{c}\bar{s}$ tetraquarks in both the hidden-charm channels $J/ψϕ$, $η_cϕ$ and open-charm channels such as $D_s\bar{D}_s^*$, $D_{s}\bar{D}_{s1}^*$ and so on.

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arXiv2022

Searching for fully-heavy tetraquark states in QCD moment sum rules

In this talk, we briefly report the investigations of the mass spectra for the $cc\bar c\bar c, bb\bar b\bar b$, $bc\bar b\bar c$ and $cc\bar b\bar b$ tetraquark states by using the QCD moment sum rule method. The calculations for the fully-charm $cc\bar c\bar c$ tetraquarks have been successfully predicted the existence of di-$J/ψ$ resonances including $X(6900)$ in LHCb's observation. The quantum numbers for these resonance structures are also suggested. More efforts are still needed in both theoretical and experimental aspects to study the properties of these fully-heavy tetraquark states. They may be observed at facilities such as LHCb, CMS and RHIC in the future.

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arXiv2021

Exotic fully-heavy $Q\bar QQ\bar Q$ tetraquark states in $\mathbf{8}_{[Q\bar{Q}]}\otimes \mathbf{8}_{[Q\bar{Q}]}$ color configuration

We have systematically calculated the mass spectra for S-wave and P-wave fully-charm $c\bar{c}c\bar{c}$ and fully-bottom $b\bar{b}b\bar{b}$ tetraquark states in the $\mathbf{8}_{[Q\bar{Q}]}\otimes \mathbf{8}_{[Q\bar{Q}]}$ color configuration, by using the moment QCD sum rule method. The masses for the fully-charm $c\bar cc\bar c$ tetraquark states are predicted about $6.3-6.5$ GeV for S-wave channels and $7.0-7.2$ GeV for P-wave channels. These results suggest the possibility that there are some $\mathbf{8}_{[c\bar{c}]}\otimes \mathbf{8}_{[c\bar{c}]}$ components in LHCb's di-$J/ψ$ structures. For the fully-bottom $b\bar{b}b\bar{b}$ system, their masses are calculated around 18.2 GeV for S-wave tetraquark states while 18.4-18.8 GeV for P-wave ones, which are below the $η_bη_b$ and $Υ(1S)Υ(1S)$ two-meson decay thresholds.

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arXiv2021

Investigation of the stability for fully-heavy $bc\bar{b}\bar{c}$ tetraquark states

We study the existence of fully-heavy hidden-flavor $bc\bar{b}\bar{c}$ tetraquark states with various $J^{PC}=0^{\pm+}, 0^{--},1^{\pm\pm}, 2^{++}$, by using the moment QCD sum rule method augmented by fundamental inequalities. Using the moment sum rule analyses, our calculation shows that the masses for the S-wave positive parity $bc\bar{b}\bar{c}$ tetraquark states are about $12.2-12.4$ GeV in both $[\mathbf{\bar{3}_c}]_{bc}\otimes[\mathbf{3_c}]_{\bar{b}\bar{c}}$ and $[\mathbf{6_c}]_{bc}\otimes[\mathbf{\bar{6}_c}]_{\bar{b}\bar{c}}$ color configuration channels. Except for two $0^{++}$ states, such results are below the thresholds $T_{η_cη_b}/T_{Υψ}$ and $T_{B_cB_c}$, implying that these S-wave positive parity $bc\bar{b}\bar{c}$ tetraquark states are probably stable against the strong interaction. For the P-wave negative parity $bc\bar{b}\bar{c}$ tetraquarks, their masses in the $[\mathbf{\bar{3}_c}]_{bc}\otimes[\mathbf{3_c}]_{\bar{b}\bar{c}}$ channel are around $12.9-13.2$ GeV, while a bit higher in the $[\mathbf{6_c}]_{bc}\otimes[\mathbf{\bar{6}_c}]_{\bar{b}\bar{c}}$ channel. They can decay into the $c\bar c+b\bar b$ and $c\bar b+b\bar c$ final states via the spontaneous dissociation mechanism, including the $J/ψΥ$, $η_cΥ$, $J/ψη_b$, $B_c^+B_c^-$ channels.

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