arXiv subjects

Wen-Jia Wang

Publications and source records attributed to Wen-Jia Wang.

6 recordsLinked to original sources

arXiv2026

Deciphering the production mechanism of the LHCb $P_c$ states

The three narrow pentaquarks $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$ observed by LHCb are widely interpreted as hadronic molecules owing to their proximity to the $Σ_c\bar{D}^{(*)}$ thresholds. However, heavy-quark spin symmetry predicts additional partner states that have not been seen experimentally, making the production mechanism in $Λ_b^0$ decays particularly important in understanding their nature. We propose a novel production mechanism, which can naturally explain why only these three LHCb $P_c$ states have been clearly observed. The $P_c(4440)$ and $P_c(4457)$ are produced via the $D_{s1}^*(2860)Λ_c(2595)\bar{D}π$ box diagram leading to $K^-Σ_c\bar{D}^{*}$, followed by rescattering into $K^- J/ψp$. The box diagram develops a box singularity in the vicinity of the $P_c(4457)$, as all four states in the box can go on shell. The $P_c$ states themselves are dynamically generated through the rescattering of the $S$-wave $Σ_c\bar{D}^{(*)}$ to $J/ψp$. The $P_c(4312)$ proceeds analogously via the $D_{s0}(2590)Λ_c(2595)\bar{D}^*π$ box diagram but without a box singularity. The near-invisibility of the $Σ_c^*\bar{D}^{(*)}$ molecular states is attributed to the suppressed production of the $Λ_c(2625)$ in $Λ_b$ weak decays, as established by the lattice QCD calculations. This mechanism naturally reproduces the data with only two production parameters, whereas previous works required 7 parameters and a finely tuned background, and provides a natural explanation for why the $Σ_c^*\bar{D}^{(*)}$ states are barely visible. It yields unique, falsifiable predictions, $Γ(Λ_b^0\to P_c(4440/4457) K\to J/ψp K)/Γ(Λ_b^0\to\bar D_{s1}^*(2860)Λ_c(2595))\approx (0.2-0.4)\%$, $Γ(Λ_b^0\to P_c(4312) K\to J/ψp K)/Γ(Λ_b^0\to \bar D_{s0}(2590)Λ_c(2595))\approx (0.2-0.8)\%$.

hep-ph↗

arXiv2026

Effective Range Expansion with the Left-Hand Cut: Higher Order Improvements

A model-independent parameterization of the low-energy scattering amplitude that incorporates the left-hand cut from one-particle exchange, an extension of the conventional effective-range expansion (ERE), was recently proposed and successfully applied to the low-energy $DD^*$ system [Phys. Rev. Lett. 135, 011903 (2025)]. While the original formulation is based on a nonrelativistic approximation and is thus limited to a [1,1] approximant for self-consistency, we extend the framework by explicitly including the higher-order terms up to $\mathcal{O}(k^6)$. We systematically investigate the reliability and robustness of the generalized ERE by incorporating relativistic kinematic effects. In addition, we develop a relativistic version of the ERE that accounts for lhc contributions. These results affirm the generalized ERE as a robust and systematically improvable framework for near-threshold scattering processes, providing both analytical and numerical reliability for applications in two-body scattering problems with a particle exchange.

hep-ph↗

arXiv2023

Strong decays of low-lying $D$-wave $Ξ_b/Ξ_b'$ baryons with QPC model

For further decoding the inner structure of the two excited $Ξ_b$ states observed by LHCb, we perform a systematical study of the strong decays of the low-lying $1D$-wave $Ξ_b$ and $Ξ_b'$ excitations using the quark pair creation model within the $j-j$ coupling scheme. Combining with the measured masses and decay properties of $Ξ_{b}(6327)^{0}$ and $Ξ_{b}(6327)^{0}$, the two excited states can be explained as $1D$ $λ$-mode $Ξ_b$ states $Ξ_{b}|J^{P}=\frac{3}{2}^{+},2\rangle_{λλ}$ and $Ξ_{b}|J^{P}=\frac{5}{2}^{+},2\rangle_{λλ}$, respectively. If such a view were correct, $Ξ_b'π$ and $Ξ_b'^*π$ could be another interesting channels for experimental exploring of the $Ξ_{b}(6327)^{0}$ and $Ξ_{b}(6327)^{0}$, respectively. Those calculations are good consistent with the results within the chiral quark model. In addition, for the other missing $1D$-wave $Ξ_b$ and $Ξ_b'$ excitations, our predictions indicate that:(i) the two $ρ$-mode $1D$ $Ξ_b$ states are likely to be moderate states with a width of $Γ\sim50$ MeV. The $J^P=3/2^+$ state dominantly decays into $Σ_bK$ and $Ξ_b'π$, while the $J^P=5/2^+$ state decays primarily through $Σ_b^*K$ and $Ξ_b'^*π$. (ii) The $λ$-mode $1D$ $Ξ_b'$ states may be moderate states with a widths of about several to dozens of MeV. Most of the $λ$-mode $1D$ $Ξ_b'$ states mainly decay into the $1P$-wave bottomed baryon via the pionic decay processes. Meanwhile, several $λ$-mode $1D$ $Ξ_b'$ states have significant decay rates into $ΛB$. (iii) While, the $ρ$-mode $1D$ $Ξ_b'$ states are predicted to be very broad states with a width of about several hundreds MeV. It will be a great challenge to explore the $ρ$-mode $1D$ $Ξ_b'$ states in experiments for their broad widths.

hep-ph↗

arXiv2023

Strong decays of the low-lying $1P$- and $1D$-wave $Σ_c$ baryons

In this work, we systematically study the OZI-allowed two-body strong decay properties of $1P$- and $1D$-wave $Σ_c$ baryons within the $j $-$j$ coupling scheme in the framework of the quark pair creation model. For a comparison, we also give the predictions of the chiral quark model. Some model dependencies can be found in the predictions of two models. The calculations indicate that: (i) The $1P$-wave $λ$-mode $Σ_c$ states most likely to be relatively narrow states with a width of $Γ<80$ MeV. Their main decay channels are $Λ_cπ$, or $Σ_cπ$, or $Σ_c^*π$. The $1P$-wave $ρ$-mode states most might be broad states with a width of $Γ\sim 100-200$ MeV. They dominantly decay into $Σ_cπ$ and $Σ_c^*π$ channels. Some evidences of these $1P$-wave states are most likely to be observed in the $Λ_cπ$ and $Λ_cππ$ invariant mass spectra around the energy range of $2.75-2.95$ GeV. (ii) The $1D$-wave $λ$-mode $Σ_c$ excitations may be moderate states with a width of about dozens of MeV. The $1D$-wave $λ$-mode states mainly decay into the $1P$-wave charmed baryon via the pionic decay processes. Meanwhile, several $1D$-wave $λ$-mode states have significant decay rates into $DN$ or $D^*N$. Hence, the $DN$ and $D^*N$ are likely to be interesting channels for experimental exploration. (iii) Furthermore, the two $1D$-wave $ρ$-mode excitations $Σ_c|J^P=5/2^+,3\rangle_{ρρ}$ and $|J^P=7/2^+,3\rangle_{ρρ}$ are most likely to be fairly narrow state with a width of dozens of MeV, and they mainly decay into $Λ_cπ$. Some evidences of them might be observed in the $Λ_cπ$ invariant mass spectra around the energy range of $3.1-3.2$ GeV.

hep-ph↗

arXiv2022

The strong decays of the low-lying $ρ$-mode $1P$-wave singly heavy baryons

We have systematically calculated the strong decays of the low-lying $ρ$-mode $1P$-wave $Λ_{c(b)}$, $Σ_{c(b)}$, $Ξ_{c(b)}$, $Ξ^{'}_{c(b)}$, $Ω_{c(b)}$ baryons using the chiral quark model within the $j$-$j$ coupling scheme. For the controversial states, our results indicate: (i) For the singly charmed heavy baryons, the newly observed $Λ_{c}(2910)^+$ is a good candidate of the $J^P=5/2^-$ state $Λ_c|J^{P}=\frac{5}{2}^{-},2\rangle_ρ$. (ii) For the singly bottom heavy baryons, the $Ξ_{b}(6227)^-$ favors the $J^{P}=5/2^{-}$ state $Ξ_{b}|J^{P}=\frac{5}{2}^{-},2\rangle_ρ$. (iii) The other missing $ρ$-mode $1P$-wave excitations in $Λ_{b}$, $Σ_{c(b)}$ and $Ξ^{'}_{c(b)}$ families appear to be broad structures with $Γ$$\sim$(100-200) MeV, and their strong decay widths are sensitive to their masses. (iv) The $ρ$-mode $1P$-wave $Ξ_{c(b)}$ and $Ω_{c(b)}$ baryons have a relatively narrow decay width of a few MeV or a few tens of MeV, and have a good potential to be observed in forthcoming experiments.

hep-ph↗

arXiv2022

The $1D$-wave bottom-strange baryons and possible interpretation of $Ξ_{b}(6327)^{0}$ and $Ξ_{b}(6333)^{0}$

Inspired by the LHCb's newest observation of two new excited $Ξ_b^0$ states, we systematically study the strong decays of the low-lying $λ$- and $ρ$-modes $1D$-wave $Ξ_{b}$ and $Ξ^{'}_{b}$ baryons using the chiral quark model within the $j$-$j$ coupling scheme. Based on the measured masses and strong decay properties of $Ξ_{b}(6327)^{0}$ and $Ξ_{b}(6333)^{0}$, we explain the two states as the $λ$-mode $1D$ $Ξ_{b}$ states with $ J^{P}=3/2^{+} $ and $ J^{P}=5/2^{+} $, respectively. Moreover, under this assignment, another dominant decay channel of $Ξ_{b}(6327)^{0}$ is $Ξ'_bπ$ and that of $Ξ_{b}(6333)^{0}$ is $Ξ_b^*π$. Hence, the decay modes $Ξ'_bπ$ and $Ξ_b^*π$ may be another ideal channels as well to decode the inner structure of $Ξ_{b}(6327)^{0}$ and $Ξ_{b}(6333)^{0}$, respectively. For other unseen $1D$ $Ξ_b$ and $Ξ'_b$ states, our results indicate: (i) $Ξ_b|J^P=\frac{3}{2}^+,2\rangle_ρ$ and $Ξ_b|J^P=\frac{5}{2}^+,2\rangle_ρ$ are most likely to be narrow states with a width of $Γ\simeq(12-30)$ MeV, and dominantly decay into $Σ_bK$ and $Σ^*_bK$, respectively; (ii) The $1D$ $Ξ'_b$ baryons are not broad states, and the widths vary in the range of $Γ\simeq(14-46)$ MeV. These states have a good potential to be observed in their dominant decay processes.

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