arXiv subjects

Hong Qiang Zhu

Publications and source records attributed to Hong Qiang Zhu.

8 recordsLinked to original sources

arXiv2022

Revealing the inner structure of the newly observed $η_1(1855)$ via photoproduction

Very recently, a new hadronic exotic state $η_1(1855)$ at the invariant mass spectrum of $ηη^{'}$ was observed by the BESIII Collaboration. According to its properties, such as the spectroscopy and decay width, the $η_1(1855)$ have been suggested to be a compact multi-quark state, a hadron molecule, or a hybrid meson. In order to distinguish the various interpretations of the $η_1(1855)$, a Reggeized model combined with the vector dominance model for $η_1(1855)$ photoproduction on the proton target is presented. If the $η_1(1855)$ is a $s\bar{s}g$ hybrid meson, the $η_1(1855)$ can be produced though the Primakoff effect. However, the $η_1(1855)$ photoproduction is dominated by the $t$-channel vector mesons $ρ$, $ω$, and $ϕ$ exchange by assuming $η_1(1855)$ as an $S$-wave $K\bar{K}_1(1400)$ molecular state. Our calculations show that the total cross section of the $η_1(1855)$ production via $γp$ reaction can reach up to 0.115 pb, about 0.0124$\%$ of the total cross section obtained by considering the $η_1(1855)$ as an $S$-wave $K\bar{K}_1(1400)$ molecule. We also find their line shapes are sizably different. If the $η_1(1855)$ is a molecular state, the photoproduction of $η_1(1855)$ near the threshold offers a nice place to test its molecular nature. However, it should be better to take high energy, at least above $E_γ=16.97$ GeV, to observe the production of $η_1(1855)$ if $η_1(1855)$ is a $s\bar{s}g$ hybrid meson. These results can be measured in the GlueX experiment or Electron-Ion Collider in China to test the nature of the $η_1(1855)$.

hep-ph↗

arXiv2022

Analysis of the $η_1(1855)$ as a $K\bar{K}_1(1400)$ molecular state

In this work, we study the radiative and strong decay of $S$-wave $K\bar{K}_1(1400)$ molecular state within the effective Lagrangians approach and find the relation between the $K\bar{K}_1(1400)$ molecular state and the newly observed $η_1(1855)$ state by comparing with the BESIII observation. The prediction indicates that the decay width can reach up to $182.97^{+2.79}_{-3.50}$ MeV, which can be confronted with the experimental data. If the $η_1(1855)$ could be $S$-wave $K\bar{K}_1(1400)$ molecular state, the $K\bar{K}^{*}π$ three-body decay provides the dominant contribution, not the $ηη^{'}$ channel found in the experiment. In addition, the partial width for $η_1(1855)\toγϕ$ can reach up to $17.95^{+0.21}_{-0.43}$ KeV. Those results can be measured in future experiments and used to test the nature of the $η_1(1855)$.

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arXiv2022

Molecular states from $\bar{B}^{(*)}N$ interactions

In 2019, two new structures $Λ_b(6146)$ and $Λ_b(6152)$ were observed by the LHCb Collaboration at the invariant mass spectrum of $Λ_b^0π^{+}π^{-}$, which aroused a hot discussion about their inner structures. The $Λ_b(6146)$ and $Λ_b(6152)$ might still be molecular states because their masses are close to threshold of a $\bar{B}$ meson and a nucleon. In this work, we perform a systematical investigation of possible heavy baryonic molecular states from the $\bar{B}N$ interaction. Since the $\bar{B}N$ channel strongly couples to the $\bar{B}^{*}N$ channel, the possible $\bar{B}N-\bar{B}^{*}N$ bound states are also studied. The interaction of the system considered is described by the $t$-channel $σ$, $π$, $η$ ,$ω$, and $ρ$ mesons exchanges. By solving the non-relativistic Schrödinger equation with the obtained one-boson-exchange potentials, the $\bar{B}^{(*)}N$ bound states with different quantum numbers are searched. The calculation suggests that recently observed $Λ_b(6146)$ can be assigned as a $P$-wave $\bar{B}N$ molecular state with spin parity $J^P=3/2^{+}$ or a $\bar{B}N-\bar{B}^{*}N$ bound state. However, assignment of $Λ_b(6152)$ as an $F$-wave $\bar{B}N$ molecular is disfavored. The $Λ_b(6152)$ can be explained as meson-baryon molecular state with a small $\bar{B}N$ component. The calculation also predict the existence of two $S$-wave $\bar{B}N-\bar{B}^{*}N$ bound states that can be related to the experimentally observed $Λ_b(5912)$ and $Λ_b(5920)$.

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arXiv2022

Possible $P$- wave $D_s\bar{D}_{s0}(2317)$ molecular state $Y^{'}(4274)$

Stimulated by the measurement of the $Jψϕ$ decay model of $Y(4274)$ by the LHCb Collaboration, we consider a possible interpretation of this state as a hadron molecular-a bound state of $D_s$ and $\bar{D}_{s0}(2317)$ mesons. Using effective Lagrangian approach, we calculate the two-body strong decay channels $Y(4274)\to{}J/ψϕ,χ_{c0}η,χ_{c0}η,D^{*}_s\bar{D}_s$, $D\bar{D}^{*}$, $K\bar{K}^{*}$, and $ϕϕ$ through hadronic loops and three-body decays into $π^0{}D_s\bar{D}_s$. In comparison with the LHCb data, our results show that $Y(4274)$ cannot be assigned to be a $D_s\bar{D}_{s0}(2317)$ molecular state. The calculated partial decay widths with $J^P=1^{+}$ $D_s\bar{D}_{s0}$ molecular state picture indicates that allowed decay modes, $χ_{c0}η$ and $χ_{c1}η$, may have the smallest branching ratio and are of the order of 0.0 MeV. Future experimental measurements of such two processes can be quite useful to test the different interpretations of the $Y(4274)$. If $P-$wave $D_s\bar{D}_{s0}$ molecular exist [we marked as $Y^{'}(4274)$], the total decay is at the order of 1.06-1.84 MeV, which seems to be within the reach of the current experiments such as Belle II. In addition, the calculated partial decay widths indicate that allowed decay mode, $D\bar{D}^{*}$, may have the biggest branching ratio. The experimental measurements for this strong decay process could be a crucial to observe such a new state $Y^{'}(4274)$.

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arXiv2021

Radiative decay of the $Ξ_c(2923)$ in a hadronic molecule picture

In the present work, we study the radiative decay of newly observed $Ξ_c(2923)^0$ based on the successful explanation that $Ξ_c(2923)^0$ is an $S$-wave $DΛ-DΣ$ molecular state in our previous study~\cite{Zhu:2020jke}. The radiative decay width of $DΛ-DΣ$ molecular state into $Ξ_c^0γ$ final state through hadronic loops are evaluated using effective Lagrangians. We find that decay width $Ξ_c(2923)^0\toΞ_c^0γ$ and $Ξ_c(2923)^0\toΞ_c^{'0}γ$ is evaluated to be approximately 1.23-11.66 KeV and 0.30-3.71 KeV, respectively. These are different from the results~\cite{Wang:2020gkn,Bijker:2020tns} that obtained by assuming $Ξ_c(2923)^0$ may be conventional charmed baryon. If measurements are in future experimental, these differences will be very useful to help us to test various interpretations of $Ξ_c(2923)^0$.

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arXiv2021

Strong decays of the $P_{cs}(4459)$ as a $Ξ_c\bar{D}^{*}$ molecule

In this work, we study the strong decay of the newly observed $P_{cs}(4459)$ assuming that it is a pure $Ξ_c\bar{D}^{*}$ molecular state. Considering two possible spin-parity assignments $J^P=1/2^{-}$ and $J^P=3/2^{-}$ the partial decay widths of the $Ξ_c\bar{D}^{*}$ molecular state into $J/ψΛ$, $D_s^{-}Λ_c^{+}$, and $DΞ_c^{(')}$ final states through hadronic loops are evaluated with the help of the effective Lagrangians. In comparison with the LHCb data, the spin-party $J^P=1/2^{-}$ the assignment is preferred while this of $J^P=3/2^{-}$ is disfavored. The $P_{cs}(4459)$ in spin-parity $J^P=3/2^{-}$ case maybe explained as $S$-wave coupled bound state with lager $Ξ_c\bar{D}^{*}$ component. In addition, the calculated partial decay widths with $J^P=1/2^{-}$ $Ξ_c\bar{D}^{*}$ molecular state picture indicates that allowed decay mode, $DΞ_c^{'}$, may have the biggest branching ratio. The experimental measurements for this strong decay process could be a crucial test for the molecule interpretation of the $P_{cs}(4459)$.

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arXiv2021

Production of the $T^{+}_{cc}$ state in the $γp\to{}D^{+}\bar{T}^{-}_{cc}Λ_c^{+}$ reaction

Stimulated by the recent LHCb observation of a new exotic charged structure $T^{+}_{cc}$, we propose to use the central diffractive mechanism existing in the $γp\to{}D^{+}\bar{T}^{-}_{cc}Λ_c^{+}$ ($\bar{T}_{cc}$ is antiparticle of $T^{+}_{cc}$) reaction to produce $T^{+}_{cc}$. Our theoretical approach is based on the chiral unitary theory where the $T^{+}_{cc}$ resonance is dynamically generated. With the coupling constant of the $T^{+}_{cc}$ to $DD^{*}$ channel obtained from chiral unitary theory, the total cross sections of the $γp\to{}D^{+}\bar{T}^{-}_{cc}Λ_c^{+}$ reaction are evaluated. Our study indicates that the cross section for $γp\to{}D^{+}\bar{T}^{-}_{cc}Λ_c^{+}$ reaction are of the order of 1.0 pb, which is accessible at the proposed EicC~\cite{Anderle:2021wcy} and US-EIC~\cite{Accardi:2012qut} due to the higher luminosity. If measured in future experiments, the predicted total cross sections can be used to test the (molecular) nature of the $T^{+}_{cc}$.

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arXiv2021

Photoproduction of possible pentaquark states $Λ^0_b(5912)$ and $Λ^0_b(5920)$ in the $γp\to{}Λ_b^{0(*)}B^+$ reactions

In this work, we report on a theoretical study of possible pentaquark states $Λ^0_b(5912)$ and $Λ^0_b(5920)$ in the $γp\to{}Λ_b^{0(*)}B^+$ reactions within an effective Lagrangian approach. In addition to the contributions from the $s$-channel nucleon pole and $t$-channel $\bar{B}^{{*}-}$ exchange, the contact term contribution are also included. Our theoretical approach is based on the chiral unitary theory where the $Λ^0_b(5912)$ and $Λ^0_b(5920)$ resonances are dynamically generated. Within the coupling constants of the $Λ^0_b(5912)$ and $Λ^0_b(5920)$ to $\bar{B}p$ and $\bar{B}^{*}p$ channels obtained from chiral unitary theory, the total and differential cross sections of the $γp\to{}Λ_b^{0(*)}B^+$ are evaluated. Our calculation indicates that the cross section for $γp\to{}Λ_b^{0}(5912)B^{+}$ and $γp\to{}Λ_b^{0}(5920)B^{+}$ reactions are of the order of 0.0164 nb and 0.00527 nb,respectively. If measured in future experiments, such as Electron-Ion Collider in China (EicC) or US(US-EIC), the predicted total cross sections and specific features of the angular distributions can be used to test the (molecular) nature of the $Λ^0_b(5912)$ and $Λ^0_b(5920)$ that they may be pentaquark states.

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