arXiv subjects

Ri-Qing Qian

Publications and source records attributed to Ri-Qing Qian.

11 recordsLinked to original sources

arXiv2026

$K(1690)$ signal from COMPASS as a strange hybrid state

A pseudoscalar resonance structure, denoted as the $K(1690)$, was recently discovered by the COMPASS Collaboration in the scattering reaction $K^-+p\to K^-π^-π^++p$. If the $K(1690)$ is a genuine state, there are three observed pseudoscalar strange mesons, namely the $K(1460)$, $K(1690)$, and $K(1830)$, in the 1.0$-$2.0 GeV region. However, within the conventional quark model, only the $2^1S_0$ and $3^1S_0$ strange meson states are expected in this energy region. Therefore, at least one of these states should be interpreted as an exotic candidate. In this work, we study the spectrum of strange mesons systematically, and find that the $K(1460)$ and $K(1830)$ are good candidates of $2^1S_0$ and $3^1S_0$ strange mesons, respectively. A further investigation of their strong decays also supports this assignment. Furthermore, we note that the production mechanism of the $K(1690)$ is similar to that of the $π_1(1600)$, which has been widely regarded as a hybrid meson candidate. We investigate the strong decays of the $K(1690)$ within a constituent gluon model by treating it as a $0^-$ strange hybrid meson and find that the results support the $K(1690)$ as a hybrid state. Finally, we identify several important decay modes of the $K(1690)$ that may be used in future experiments to test whether it contains the $n^1S_0$ ($n=$2 and 3) $s\bar{q}$ component. We also suggest BESIII to search for the $K(1690)$ state through the $J/ψ\to K K(1690) \to KK^{\ast}_0(1430)π\to KKππ$ process.

hep-ph↗

arXiv2026

Revisiting charmonium hybrid spectroscopy

Hadrons with explicit gluonic degrees of freedom, such as charmonium hybrids, are key to understanding nonperturbative behavior of strong interaction, yet they remain experimentally elusive. Within a constituent gluon model treating the hybrid as a $c\bar{c}g$ three-body system with a transverse electric gluon, we predict the masses of the lightest hybrid multiplet ($J^{PC}=1^{--}, 0^{-+}, 1^{-+}, 2^{-+}$) to lie in the range $4.19$--$4.32$ GeV. By analyzing their decay patterns, we provide specific, experimentally testable signatures to guide the search for these exotic states at current and future facilities.

hep-ph↗

arXiv2025

Unified coupled-channel description for the five near-threshold structures $ψ(3770)$, $G(3900)$, $R(3760)$, $R(3780)$ and $R(3810)$ from $e^+e^-$ annihilation

The recent observation of multiple near-threshold structures in $e^+e^-$ annihilation-including $ψ(3770)$, $G(3900)$, $R(3760)$, $R(3780)$, and $R(3810)$-reveals limitations in existing models of charmonium and exotic hadrons. In this paper, we propose a unified coupled-channel description that simultaneously incorporates all five near-threshold structures using parameters constrained by hadron spectroscopy. Our model accurately reproduces the line shapes in both $D\bar{D}$ and nonopen-charm hadron (nOCH) channels, resolves the asymmetric profile of $ψ(3770)$, and produces the $G(3900)$ bump. We identify the $R(3780)$ as the dominant manifestation of $ψ(3770)$, attribute $R(3760)$ to $D\bar{D} \to \text{nOCH}$ rescattering and suggest that $R(3810)$ arises from coupling between the $ψ(1D)$ state and the $h_cππ$ channel. The significant non-$D\bar{D}$ decay of $ψ(3770)$ is explained by its near-threshold position. This analysis provides a coherent, unquenched framework centered on a charmonium $ψ(1D)$ core for near-threshold phenomena and offers a predictive approach extendable to bottomonium systems and future data from Belle II.

hep-ph↗

arXiv2025

Discovery potential of charmonium $2P$ states through the $e^+e^- \to γD\bar{D}$ processes

In this work, we investigate the production of charmonium $2P$ states via the $e^+e^-\to γD\bar{D}$ process at $\sqrt{s} = 4.23$ GeV. Using the measured cross-section data for $e^+e^-\to γX(3872)$ as a reference, we calculate the cross sections for $e^+e^-\to γχ_{c0}(2P)$ and $e^+e^-\to γχ_{c2}(2P)$. Since the $χ_{c0}(2P)$ and $χ_{c2}(2P)$ states predominantly decay into $D\bar{D}$ final states, we also predict the corresponding $D\bar{D}$ invariant mass spectrum for the $e^+e^-\to γD\bar{D}$ process. Our results indicate that $e^+e^-\to γD\bar{D}$ is an ideal process for identifying the $χ_{c0}(2P)$ and $χ_{c2}(2P)$ states, analogous to the $γγ\to D\bar{D}$ and $B^+\to D^+D^-K^+$ processes. This study highlights the discovery potential of charmonium $2P$ states at BESIII and Belle II.

hep-ph↗

arXiv2025

Finding Interaction Mechanism between Exotic Molecule and Conventional Hadron

An intriguing and important question arises: how do hadronic molecules interact with conventional hadrons? In this work, we propose a novel mechanism to address this issue, focusing on the interactions between hidden-charm molecular pentaquarks ($P_c$) and nucleons ($N$). By applying this mechanism, we derive the corresponding interaction potentials, enabling the prediction of the bound state properties. Our results indicate the possible existence of $P_cN$ bound states-an entirely new form of matter, ripe for exploration in the era of high-precision hadron spectroscopy. Notably, this mechanism extends beyond the $P_cN$ systems and can be applied to any hadronic molecules interacting with conventional hadrons, offering the potential for discovering a variety of novel bound states.

hep-ph↗

arXiv2024

Spectroscopic Properties of Double-Strangeness Molecular Tetraquarks

Inspired by recent advances in the study of the $K^{(*)} \bar K^{(*)}$ molecular tetraquarks and the $H$-dibaryon, we focus on the spectroscopic properties of the $\bar K^{(*)} \bar K^{(*)}$ systems, which exhibit exotic flavor quantum number of $ss\bar q \bar q$. A dynamical analysis is performed using the one-boson-exchange model to describe the effective interactions for these systems, accounting for both $S$-$D$ wave mixing and coupled-channel effects. By solving the coupled-channel Schr$\ddot{\rm o}$dinger equation, we identify the $I(J^P)=0(1^+)$ $\bar K \bar K^*$ and $I(J^P)=0(1^+)$ $\bar K^* \bar K^*$ states as the most likely candidates for double-strangeness molecular tetraquarks. Furthermore, we estimate their strong decay behaviors based on the effective Lagrangian approach, with several channels exhibiting considerable decay widths. Meanwhile, we investigate their magnetic moments and M1 radiative decay widths, shedding light on their inner structures, within the constituent quark model. Finally, we encourage experimentalists to focus on these predicted double-strangeness molecular tetraquark candidates, particularly in $B$ meson decays. Such efforts could pave the way for establishing the molecular tetraquark states in the light-quark sector.

hep-ph↗

arXiv2023

Production of charmonium $χ_{cJ}(2P)$ plus one $ω$ meson by $e^+e^-$ annihilation

Inspired by the recent observation of $e^+e^-\to ωX(3872)$ by the BESIII Collaboration, in this work we study the production of the charmonium $χ_{cJ}(2P)$ by $e^+e^-$ annihilation. We find that the $e^+e^-\toωχ_{c0}(2P)$ and $e^+e^-\to ωχ_{c2}(2P)$ have sizable production rates, when taking the cross section data from $e^+e^-\to ωX(3872)$ as the scaling point and treating the $X(3872)$ as the charmonium $χ_{c1}(2P)$. Considering that the dominant decay modes of $χ_{c0}$ and $χ_{c2}(2P)$ involve $D\bar{D}$ final states, we propose that $e^+e^-\to ωD\bar{D}$ is an ideal process to identify $χ_{c0}(2P)$ and $χ_{c2}(2P)$, which is similar to the situation that happens in the $D\bar{D}$ invariant mass spectrum of the $γγ\to D\bar{D}$ and $B^+\to D^+{D}^- K^+$ processes. With continuous accumulation of experimental data, these proposed production processes offer a promising avenue for exploration by the BESIII and Belle II collaborations.

hep-ph↗

arXiv2023

Toy model to understand oscillatory behavior in timelike nucleon form factors

To understand the oscillatory behavior exhibited in the timelike electromagnetic form factors of nucleons, we propose a toy model based on the Jost function of the $N\bar N$ pair into the timelike form factors with the help of the distorted-wave Born approximation. By constructing a simple square-well potential reflecting the final-state interaction of $N\bar N$, we naturally represent the damped oscillatory phenomenon in the timelike electromagnetic form factors of nucleons. Especially, our study reveals that the ``period" of the oscillation is approximately determined by the Yukawa interaction range $1/m_π$. Other possible potentials are also discussed. The threshold enhancements of the cross sections for $e^+e^-\to n\bar n$, $Λ\barΛ$, and $Λ_c\barΛ_c$ can also be understand within this scenario.

nucl-th↗

arXiv2022

Predicted $Λ\barΛ$ and $Ξ^-\barΞ^+$ decay modes of the charmoniumlike $Y(4230)$

In this work, we predict the light hadronic decay channels $Y(4230)\toΛ\barΛ$ and $Ξ^-\barΞ^+$ when treating the $Y(4230)$ as a vector charmonium state. By the hadronic loop mechanism, the branching ratios of the $Y(4230)\toΛ\barΛ$ and $Ξ^-\barΞ^+$ processes are calculated. In addition, we discuss the possibility of carrying out the search for the signal of the $Y(4230)$ through $Λ\barΛ$ and $Ξ^-\barΞ^+$ channels from the $e^+e^-$ annihilation. Assuming $Y(4230)$ exist in $Λ\barΛ$ and $Ξ^-\barΞ^+$ channel, we also present the time-like electromagnetic form factors (EMFFs) at $\sqrt{s}=m_{Y(4230)}$.

hep-ph↗

arXiv2021

Charmonium decays into $Λ_c\barΛ_c$ pair governed by the hadronic loop mechanism

In this work, we investigate the open-charm decay process $ψ\toΛ_c\barΛ_c$ via the hadronic loop mechanism for vector charmonia above $Λ_c\barΛ_c$ threshold. The branching ratios of these vector charmonium states to $Λ_c\barΛ_c$ are estimated. The charmonium explanation of the $Y(4630)$ observed in $e^+e^- \to Λ_c\barΛ_c$ is tested. Furthermore, for the predicted higher vector charmonia above 4.7 GeV, the branching ratios $\mathcal{B}[ψ(nS)\toΛ_c\barΛ_c]$ with $n=7,8,9$ are found to be of the order of magnitude of $10^{-4}-10^{-3}$ while $\mathcal{B}[ψ(mD)\toΛ_c\barΛ_c]$ with $m=6,7,8$ are of the order of magnitude of $10^{-3}-10^{-2}$. The experimental signals of these missing charmonium states are discussed. The search for them may be an interesting topic in the future BESIII and Belle II experiments.

hep-ph↗

arXiv2020

Are the $Y$ states around 4.6 GeV from $e^+e^-$ annihilation higher charmonia?

In this work, we present the mass spectrum of higher charomona around and above 4.6 GeV by adopting the unquenched potential model. We perform a combined fit to the updated experimental data of $e^+e^- \to ψ(2S)π^+π^-$ and $e^+e^-\to Λ_c\barΛ_c$. To understand the "platform" structure observed in the range of $4.57 \sim 4.60$ GeV existing in the $Λ_c\barΛ_c$ invariant mass spectrum of $e^+e^-\to Λ_c\barΛ_c$ of BESIII, we introduce two resonances in this combined fit to the $e^+e^- \to ψ(2S)π^+π^-$ and $e^+e^-\to Λ_c\barΛ_c$, which have resonance parameters, $m_{Y_1}=4585\pm2$ MeV, $Γ_{Y_1}=29.8\pm8.0$ MeV, $m_{Y_2}=4676\pm7$ MeV, and $Γ_{Y_2}=85.7\pm15.0$ MeV. Furthermore, combining with our theoretical results, we indicate that the two charmonium-like $Y$ states can be due to two higher charmonia, which are mixtures of $6S$ and $5D$ $c\bar{c}$ states. Their two-body open-charm decay behaviors are given. Under the same framework, our analysis of the data of $e^+e^-\to D_{s}^+D_{s1}(2536)^-$ recently released by Belle supports to introduce these two higher charmonia around 4.6 GeV. Additionally, we predict the masses and two-body open-charm decays of six higher charmonia $ψ(nS)$ and $ψ(mD)$ with $n=7,8,9$ and $m=6,7,8$ above 4.6 GeV. Search for these higher charmonia will be an interesting issue for the running BESIII and BelleII, and even the possible Super Tau-Charm Factory discussed in China.

hep-ph↗