arXiv subjects

Shi-Qing Kuang

Publications and source records attributed to Shi-Qing Kuang.

4 recordsLinked to original sources

arXiv2023

Study of $X(6900)$ with unitarized coupled channel scattering amplitudes

In this paper, we study the resonant state $X(6900)$. The scattering amplitudes of coupled channels, $J/ψJ/ψ$-$J/ψψ(2S)$-$J/ψψ(3770)$, are constructed with the interaction of four vector mesons described by effective Lagrangians. The amplitudes are calculated up to one loop, decomposed by partial wave projection, and unitarized by Pad$\acute{e}$ approximation. These amplitudes are fitted to the latest experimental data sets of di-$J/ψ$ and $J/ψψ(2S)$ invariant mass spectra of LHCb, CMS, and ATLAS. High-quality solutions are obtained. With these partial wave amplitudes, we extract the pole parameters of the $X(6900)$. Its quantum number is likely to be $0^{++}$. According to the pole counting rule as well as analysis of the phase shifts of the partial waves, it supports our previous conclusion that the $X(6900)$ prefers to be a compact tetra-quark.

hep-ph↗

arXiv2022

Nature of the $X(6900)$ in partial wave decomposition of $J/ψJ/ψ$ scattering

In this letter, we perform partial wave decomposition on coupled-channel scattering amplitudes, $J/ψJ/ψ$-$J/ψψ(2S)$-$J/ψψ(3770)$, to study the resonance appears in these processes. Effective Lagrangians are used to describe the interactions of four charmed vector mesons, and the scattering amplitudes are calculated up to the next-to-leading order. Partial wave projections are performed, and unitarization is implemented by Padé approximation. Then we fit the amplitudes to the $J/ψJ/ψ$ invariant mass spectra measured by LHCb and determine the unknown couplings. The pole parameters of the $X(6900)$ are extracted as $M=6861.0^{+6.3}_{-8.8}$~MeV and $Γ=129.0^{+5.6}_{-3.4}$~MeV. Our analysis implies that its quantum number prefers to be $0^{++}$. The pole counting rule and phase shifts show that it is a normal Breit-Wigner resonance and, hence, should be a compact tetraquark.

hep-ph↗

arXiv2022

Nature of $X(2370)$

We address the nature of the $X(2370)$ resonance observed in the $J/ψ$ radiative decays, $J/ψ\rightarrowγK^{+} K^{-}η'$, $J/ψ\rightarrowγK_S K_Sη'$ and $J/ψ\rightarrowγπ^{+}π^{-}η'$. By studying the invariant mass spectra we confirm that decays of the $X(2370)$ into three pseudo-scalars are well described by an effective chiral Lagrangian. We extract the branching ratio of $J/ψ\to X(2370)γ$ and show that it is an order of magnitude larger compared to the glueball production rate predicted by lattice QCD. This indicates that $X(2370)$ is not likely to be a glueball candidate.

hep-ph↗

arXiv2020

Pole analysis on the hadron spectroscopy of $Λ_b\to J/Ψp K^-$

In this paper we study the $J/Ψp$ spectroscopy in the process of $Λ_b\to J/Ψp K^-$. The final state interactions of coupled channel $J/Ψp$ ~-~ $\bar{D} Σ_c$~-~$\bar{D}^{*} Σ_c$ are constructed based on K-matrix with the Chew-Mandelstam function. We build the $Λ_b\to J/Ψp K^-$ amplitude according to the Au-Morgan-Pennington method. The event shape is fitted and the decay width of $Λ_b\to J/Ψp K^-$ is used to constrain the parameters, too. With the amplitudes we extract out the poles and their residues. Our amplitude and pole analysis suggest that the $P_c(4312)$ should be $\bar{D}Σ_c$ molecule, the $P_c(4440)$ could be an S-wave compact pentaquark state, and the structure around $P_c(4457)$ is caused by the cusp effect. The future experimental measurement of the decays of $Λ_b\to \bar{D}Σ_c K^-$ and $Λ_b\to \bar{D}^*Σ_c K^-$ would further help to study the nature of these resonances.

hep-ph↗