arXiv subjects

Wei-Hong Liang

Publications and source records attributed to Wei-Hong Liang.

At least 19 recordsLinked to original sources

arXiv2026

Theoretical description of the $D^{+} \to \bar{K}^{0} \pi^{+} \pi^{0} \pi^{0}$ reaction

We study the $D^{+} \rightarrow \bar{K}^{0} \pi^{+} \pi^{0} \pi^{0}$ reaction, which shows two clear structures: the $\bar{K}^{*0}$ and $\rho^{+}$ in the $\bar{K}^{0} \pi^{0}$ and $\pi^{+} \pi^{0}$ mass distributions, respectively. The study is done starting from the quark level with external and internal emission and hadronizing a pair of quarks to produce a vector and two pseudoscalars. We also consider another mechanism, which does not require hadronization of quark pairs: the direct production of $\bar{K}^{*0}$ and $\rho^{+}$. With the help of six unknown parameters which are fitted to the data, we are able to get a very good agreement with experimental data for the $\bar{K}^{0} \pi^{0}$ and $\pi^{+} \pi^{0}$ mass distributions and a qualitative one for the rest of mass distributions which do not show any particular structure experimentally.

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arXiv2026

Scattering data and correlation function for the $K f_1(1285)$ interaction

We study the interaction of a kaon with the $f_1(1285)$ resonance, assuming that the $f_1(1285)$ is a molecular state generated by the $K \bar K^*, \bar K K^*$ interaction, evaluating the scattering amplitude, the scattering length and effective range of the $K f_1$ system. The scattering amplitude develops a resonant structure approximately \R{$56$ MeV} below the $K f_1$ threshold, with a width of around \R{$123$ MeV} MeV. The corresponding correlation function has the distinctive shape of a system with a bound state close to threshold. We also show that the interaction of the $K f_1$ system differs significantly from the one obtained assuming that the $f_1(1285)$ is an \R{ordinary, non-molecular,} particle. This provides motivation to continue the search for these observables, already initiated by the measurement of the $p f_1(1285)$ correlation function by the ALICE collaboration.

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arXiv2026

In search for signals of the $D\bar{D}$ bound state $X(3700)$ from study of the $B^+ \to D^+ D^- K^+$, $B^0 \to D^+ D^- K^0$ and $\Lambda_b \to D^+ D^- \Lambda$ reactions

We perform a theoretical study of the $B^+ \to D^+ D^- K^+$, $B^0 \to D^+ D^- K^0$ and $\Lambda_b \to D^+ D^- \Lambda$ reactions by looking at the production mechanisms, with special emphasis in the final state interaction of the charmed mesons, which gives rise to the $X(3930)$, coupling strongly to $D_s\bar{D}_s$, and another state that we call $X(3700)$, coupling strongly to $D \bar D$ that qualifies as a $D \bar D$ bound state. The combined study of all these reactions shows that the final state interaction responsible for the production of these resonances is more important in the $B^+ \to D^+ D^- K^+$ reaction than in the $\Lambda_b \to D^+ D^- \Lambda$ one. We have taken this into account and shown that normalizing the $D^+ D^-$ mass distributions to the same value at the peak of the $\psi(3770)$ production, the two mass distributions are quite different in a range of 10 MeV above the $D^+ D^-$ threshold, with a value about an order of magnitude bigger for the $B^+ \to D^+ D^- K^+$ reaction than for the $\Lambda_b \to D^+ D^- \Lambda$ one. The $D^+D^-$ mass distribution by itself also shows an enhancement of about one order of magnitude in the presence of the $X(3700)$ with respect to a calculation where this resonance is absent. We make a call to measure these magnitudes in the coming LHCb upgrades, which would bring great support to the existence of the bound $D^+ D^-$ state.

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arXiv2026

The $B^{+(0)} \to \bar D^{0(-)} D^{}_{s0}(2317)^+$ decays and the molecular structure of $D^_{s0}(2317)$

We have conducted a study of the $B^{+(0)} \to \bar D^{0(-)} D^{*}_{s0}(2317)^+$ reactions from the perspective that the $D^*_{s0}(2317)$ resonance is a molecular state of the $DK$ and $D_s η$ components. We have followed a method to evaluate the branching fractions obtaining information from the experimental data on the $B^+\to \bar D^0 K^+ D^0$, $B^+\to \bar D^0 K^0 D^+$, $B^0 \to D^- K^+ D^0$, $B^0 \to D^- K^0 D^+$ reactions, which have the $D^0 K^+$ and $D^+ K^0$ pairs in the final state. The approach concentrates the dynamics of the weak process in the branching ratios of these reactions and pays attention to the propagation of the $DK$ components and their strong interaction to form the $D^*_{s0}(2317)$ resonance. By means of two free parameters, we are able to describe these six rates, showing consistency with the molecular picture of the $D^*_{s0}(2317)$ state.

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arXiv2026

Interaction and correlation functions for $\pi f_1(1285)$, $\eta f_1(1285)$

We have studied the interaction of $\pi^0 (\eta) f_1(1285)$ assuming the $f_1(1285)$ to be a molecular state of $K^* \bar K - \bar K^* K$. We use a framework in which a $\pi^0 (\eta) f_1(1285)$ optical potential is obtained, which is later used as the kernel of the Lippmann-Schwinger equation, following the standard method for the interaction of particles with nuclei. The optical potential is obtained using the fixed center approximation to the Faddeev equations, where a cluster, here the $f_1(1285)$, remains unchanged during the interaction, appropriate to the situation that one has here. We have obtained the scattering matrix for this system, the scattering length and effective range, plus the correlation functions. The framework used has been previously tested in the study of the $p f_1(1285)$ interaction and has been shown to give results in agreement with the recent experimental measurement of the $p f_1(1285)$ correlation function. On the other hand, from this interaction we do not obtain clear signals for the $\pi_1(1400)$ or $\pi_1(1600)$, nor for the $\eta_1(1855)$ resonances, which in other approaches have been claimed to arise from the same dynamics. We, however, obtain a structure in the $\pi^0 f_1(1285)$ amplitude around $1500-1600{\; \rm MeV}$ and a strong cusp at the $\eta f_1(1285)$ threshold of $1833 {\; \rm MeV}$.

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arXiv2026

Correlation function and bound state from the $K D_{s0}^*(2317)$ interaction

In anticipation of the new wave of ALICE experiments on particle-resonance correlation functions, we study the interaction of a kaon with the $D_{s0}^*(2317)$ resonance. Assuming the $D_{s0}^*(2317)$ to be a $DK$ molecular state in isospin $I=0$, we employ the fixed center approximation (FCA) to describe the kaon scattering off the $DK$ cluster, and implement elastic unitarity in the $K D_{s0}^*(2317)$ amplitude via an optical potential and the Lippmann-Schwinger equation. We evaluate the scattering length, effective range, and correlation function, which exhibits a shape characteristic of a strongly attractive interaction. Notably, the amplitude develops a narrow resonant peak about 40~MeV below the $K D_{s0}^*(2317)$ threshold, signaling a three-body bound state. We discuss the experimental feasibility of observing this state through the invariant mass distribution of $K D_s^+ π^0$, and argue that such three-body states, predicted by various theoretical approaches, offer promising targets for future experimental searches, providing valuable insights into the nature of exotic hadronic resonances.

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arXiv2026

The $D_{s0}^(2317)^+$ decay to $D_s^+π^0$ and $D_s^{+}γ$

We study the strong decay of $D_{s0}^*(2317)^+$ to $D_s^+ π^0$ considering the coupled channels of $D^0 K^+, D^+ K^0, D_s^+ η$ and $D_s^+ π^0$ within a picture for the interaction based on the local hidden gauge approach. We also address the problem of the radiative decay to $D_s^{*+} γ$, using the same information obtained from the molecular picture. We obtain a strong width of the $D_{s0}^*(2317)^+$ of about $77 \,\rm keV$ from coupled channels interaction and a radiative decay of about $1.7 \,\rm keV$. We also show that the extra consideration of $π^0-η$ mixing can double the strong decay width to values around $140 \,\rm keV$. The anomalous terms for the radiative decay are considered for the first time, but they are found negligible. We make a thorough discussion of this and other results to the light of the recent measurement of Belle for the ratio of these two decay modes, and make a call for the precise measurement of the two decay widths independently to clarify the present situation concerning the nature of the $D_{s0}^*(2317)^+$ state.

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arXiv2026

$a_0(980)$ production, triangle singularity, and non-$ϕ$ background in the $J/ψ\to ϕηπ^0$ reaction

We study the $J/ψ\toϕηπ^{0}$ reaction measured recently by the BESIII collaboration with high precision, paying attention to three important aspects: 1) The production of the $a_0(980)$ in the $π^0η$ mass distributions, with the typical narrow width observed in isospin violating processes; 2) The origin of two peaks in the $ϕπ^{0}$ mass distributions that were branded as ``non $ϕ$" contribution in the experimental analysis; 3) The existence of two triangle mechanisms developing a triangle sigularity at the same energy where the ``non $ϕ$" contribution peaks in the experiment. However, we also show that the strength of these peaks is very small relative to the observed ones, a feature which is tied to the experimental technique used to identify the $ϕ$ looking at $K^+K^-$ in a narrow window of invariant mass around the $ϕ$ mass. We suggest that these triangle singularities could be observed with other methods to identify the $ϕ$.

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arXiv2026

Superexotic $K^{+}D^{+}K^{*+}$ bound state

We study a system made from $K^{*+}D^{*+}K^{*+}$ with charge $3$, isospin $I=3/2$, spin $J=3$, and a quark content of $c\bar d \bar s u \bar s u$, which make it highly exotic relative to the standard $q\bar q$ structure of mesons. The interaction of the three body system is obtained starting from a cluster of $K^{*+}D^{*+}$ in $I=1$ and $J=2$, that in different works has been found bound, and adding to it an extra $K^{*+}$ with spin aligned with those of the vectors of the cluster. We find that the $K^* K^*$ interaction in $I=1$ and $J=2$ is repulsive, but its strength is small compared to that of $K^{*+}D^{*+}$ in $I=1$ and $J=2$, such that we find a three body state bound by about $100 \, \rm MeV$ with respect to the mass of a $K^{*+}$ and the $K^{*+} D^{*+}$ cluster. The width of the state, of about $10\, \rm MeV$, is much smaller than the binding, which facilitates its observation. We suggest to find that state by measuring the invariant mass of $K D K^*$, something feasible in present experimental facilities.

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arXiv2025

$J/ψΛ$ femtoscopy and the nature of $P_{ψs}^Λ(4338)$

Over the past two decades, numerous exotic hadron states have been discovered, yet their underlying nature remains unclear. It is widely acknowledged that understanding hadron-hadron interactions is essential to unraveling their properties. Hadron spectroscopy is a powerful tool for this endeavor, providing rich experimental data that can shed light on exotic systems. Recently, the LHCb experiment analyzed the process $B^{-} \rightarrow J/ψΛ\bar{p}$ and observed a narrow peak in the $J/ψΛ$ invariant mass spectrum, regarding it as a candidate for a pentaquark. In this work, we extract the coupled-channel $J / ψΛ-\bar{D} Ξ_c-\bar{D}_s Λ_c$ potential based on the $J/ψΛ$ invariant mass spectrum. Our results indicate the existence of a bound state below the $\bar{D} Ξ_c$ mass threshold, corresponding to the experimentally measured state $P_{cs}(4338)$. Furthermore, we predict the scattering lengths and momentum correlation functions for the $J/ψΛ$ and $\bar{D}Ξ_c$ channels, which serve as theoretical references for future femtoscopy experiments.

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arXiv2025

The role of the $f_0(1710)$ and $a_0(1710)$ resonances in the $D^0 \to ρ^0 ϕ$, $ωϕ$ decays

We study the $D^0 \to ρ^0 ϕ$, $ωϕ$ decays which proceed in a direct mode via internal emission with equal rates. Yet, the experimental branching ratio for the $ρ^0 ϕ$ mode is twice as big as that for the $ωϕ$ mode. We find a natural explanation based on the extra indirect mechanism where $K^{*+} K^{*-}$ is produced via external emission and that channel undergoes final state interaction with other vector--vector channels to lead to the $ρ^0 ϕ$, $ωϕ$ final states, with transition amplitudes dominated by the $a_0(1710)$ resonance, recently discovered, and $f_0(1710)$ respectively. The large coupling of the $a_0(1710)$ to the $ρ^0 ϕ$ channel is mostly responsible for this large ratio of the production rates.

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arXiv2025

Determination of the binding and $DK$ probability of the $D^{*}_{s0}(2317)$ from the $(\bar{D}\bar K)^-$ mass distributions in $Λ_{b}\to Λ_{c} (\bar{D}\bar K)^-$ decays

We study the $Λ_{b}\toΛ_{c}\bar{D}^{0}K^{-}$ and $Λ_{b}\to Λ_{c}D^{-}\bar{K}^{0}$ decays which proceed via a Cabibbo and $N_c$ favored process of external emission, and we determine the $\bar{D}^{0}K^{-}$ and $D^{-}\bar{K}^{0}$ mass distributions close to the $\bar{D} \bar{K}$ threshold. For this, we use the tree level contribution plus the rescattering of the meson-meson components, using the extension of the local hidden gauge approach to the charm sector that produces the $D^*_{s0}(2317)$ resonance. We observe a large enhancement of the mass distributions close to threshold due to the presence of this resonance below threshold. Next we undertake the inverse problem of extracting the maximum information on the interaction of the $\bar{D} \bar{K}$ channels from these distributions, and using the resampling method we find that from these data one can obtain precise values of the scattering lengths and effective ranges, the existence of an $I=0$ bound state with a precision of about $4 \;\rm MeV$ in the mass, plus the $\bar{D} \bar{K}$ molecular probability of this state with reasonable precision. Given the fact that the $Λ_{b}\toΛ_{c}\bar{D}^{0}K^{-}$ decay is already measured by the LHCb collaboration, it is expected that in the next runs with more statistics of the decay, these mass distributions can be measured with precision and the method proposed here can be used to determine the nature of the $D^*_{s0}(2317)$, which is still an issue of debate.

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arXiv2025

The $Λ_c^+\toΛπ^+π^+π^-$ reaction, and a triangle singularity producing the $Σ^*(1430)$ state

We study the decay $Λ_c^+ \to Λπ^+ π^+ π^-$, focusing on the production of the $Σ^*(1430)$ resonance observed by the Belle Collaboration. Interpreted as a dynamically generated state from meson-baryon interactions in the chiral unitary approach, the $Σ^*(1430)$ signal is shown to be enhanced by a triangle singularity involving intermediate $K^{*-}$, $p$, and $\bar K^0$ states. This mechanism leads to a sharp peak near 1434 MeV in the $π^+ Λ$ invariant mass distribution, in agreement with the experimental observations, and predicts a secondary peak around 1875 MeV in the $π^- Σ^*(1430)$ spectrum tied to the triangle singularity. We also estimate the branching ratio of $Λ_c^+ \to π^+ π^- Σ^*(1430)$ to be about $3.5 \times 10^{-4}$. The results for the branching ratio and the $π^- Σ^*(1430)$ mass distributions are predictions of the theoretical approach, which could be tested with reanalysis of existing data.

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arXiv2025

Determination of the $K^+\bar{K}^0$ scattering length and effective range from the $D^+\to\bar{K}^0π^+η$ reaction

We study the scattering parameters of the $K^+\bar{K}^0$ system through the analysis of the $D^+\to\bar{K}^0π^+η$ reaction, aiming at determining the scattering length $a$ and effective range $r_0$ of the $K^+\bar{K}^0$ interaction. These parameters are extracted by analyzing and fitting the mass distributions of the pairs in the final $\bar{K}^0π^+η$ state. To ensure the reliability of the results, we apply resampling techniques to evaluate statistical uncertainties and improve the precision of the scattering parameters. The obtained results are compared with previous theoretical predictions and experimental data, providing new insights into the $K^+\bar{K}^0$ interaction at low energies.

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arXiv2024

Testing the molecular nature of the $Ω(2012)$ with the $ψ(3770) \to \barΩ \bar{K} Ξ$ and $ψ(3770) \to \barΩ \bar{K} Ξ^*(1530) (\bar Ω\bar K πΞ)$ reactions

We report on the reactions $ψ(3770)\to \barΩ^+ \bar{K} Ξ$ and $ψ(3770)\to \barΩ^+ \bar{K}Ξ^*(1530)~(Ξ^*(1530)\to πΞ$), and calculate the mass distributions $\frac{{\rm d}Γ}{{\rm d}M_\text{inv}(\bar{K}Ξ)}$ and $\frac{{\rm d}Γ}{{\rm d}M_\text{inv}(\bar{K}Ξ^*)}$, respectively. We obtain clear peaks corresponding to the $Ω(2012)$. From the decay of $ψ(3770)\to \barΩ^+ \bar{K}Ξ^*$, we also get a second, broader, peak around $2035\,\rm MeV$, which comes from the $Ω(2012)$ decay to $\bar{K}Ξ^*$. This second peak is closely tied to the molecular picture of the $Ω(2012)$ with the $\bar{K}Ξ^*(1530)$ and $ηΩ$ components. Its observation would provide a boost to the molecular picture of the $Ω(2012)$.

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arXiv2024

$P_c(4440)$ and $P_c(4457)$ decay into $\bar{D}Σ_c$ and $\bar{D}Λ_c$ and the spin of the $P_c$ states

We address the issue of the width and spin assignment of the $P_c(4440)$ and $P_c(4457)$ pentaquark states. We calculate the partial decays widths of the particles into $J/ψN$, $\bar{D} Σ_c$ and $\bar{D} Λ_c$ with the first one obtained within a unitary approach with the coupled channels of $J/ψN$ and $\bar{D}^* Σ_c$ with the interaction driven by vector meson exchange, and the last two by means of triangle diagrams involving pion exchange which break the spin degeneracy of the vector meson exchange. The widths obtained depend much on the spin of the particles and we study the possible scenarios for spin assignment, favoring the $1/2^-$ , $3/2^-$ order. We predict values for decays in different channels and show that their determination would allow to decide unambiguously the spin of the states.

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arXiv2024

How to unravel the nature of the $Σ^*(1430) (1/2^-)$ state from correlation functions

We calculate the correlation functions for the $\bar K^0 p, π^+ Σ^0, π^0 Σ^+, π^+ Λ$, and $ηΣ^+$ states, which in the chiral unitary approach predict an excited $Σ^*(1/2^-)$ state at the $\bar K N$ threshold, recently observed by the Belle Collaboration. Once this is done, we tackle the inverse problem of seeing how much information one can obtain from these correlation functions. With the resampling method, one can determine the scattering parameters of all the channels with relative precision by means of the analysis in a general framework, and find a clear cusplike structure corresponding to the $Σ^*(1/2^-)$ in the different amplitudes at the $\bar{K}N$ threshold.

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arXiv2024

One or two poles for the $Ξ(1820)$?

In this talk, we present a new interpretation for the recently observed $Ξ(1820)$ resonance. We recall that the chiral unitary approach for the interaction of pseudoscalar mesons with the baryons of the decuplet predicts two states for the $Ξ(1820)$ resonance, one with a narrow width and the other one with a large width. We contrast this fact with the recent BESIII measurement of the $K^- Λ$ mass distribution in the $ψ(3686)$ decay to $K^- Λ\barΞ^+ $, which demands a width much larger than the average of the PDG, and show how the consideration of the two $Ξ(1820)$ states provides a natural explanation to this apparent contradiction.

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