arXiv subjects

Xian-Hui Zhong

Publications and source records attributed to Xian-Hui Zhong.

At least 37 records · Page 2Linked to original sources

arXiv2023

Charmonia in an unquenched quark model

In this work, we study the charmonium spectrum within an unquenched quark model including coupled-channel effects. In couple-channel calculations, we include all of the opened charmed meson channels with the once-subtracted method, meanwhile adopt a suppressed factor to soften the hard vertices given by the $^3P_0$ model in the high momentum region. We obtain a good description of both the masses and widths for the well-established states in the charmonium spectrum. Furthermore, we give predictions for the higher $S$-, $P$- and $D$-wave charmonium states up to mass region of $\sim 5.0$ GeV. The magnitude of mass shifts due to the coupled-channel effects is estimated to be about $10s$ MeV. Although many decay channels are opened for the higher charmonium states, they are relatively narrow states. Their widths scatter in the range of $\sim 10s-100$ MeV. Many charmonium-like states, such as $χ_{c1}(3872)$, $χ_{c1}(4274)$, $χ_{c0}(3915)$, $χ_{c0}(4500)$, $χ_{c0}(4700)$, $X(4160)$, $X(4350)$, $Y(4500)$, and $ψ(4660)$/$Y(4710)$, can be accommodated by the charmonium spectrum when the unquenched coupled-channel effects are carefully considered.

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arXiv2023

Unified unquenched quark model for heavy-light mesons with chiral dynamics

In this work, an unquenched quark model is proposed for describing the heavy-light mesons by taking into account the coupled-channel effects induced by chiral dynamics. After including a relativistic correction term for the strong transition amplitudes, both the mass spectra and decay widths of the observed heavy-light mesons can be successfully described simultaneously in a unified framework, several long-standing puzzles related to the small masses and broad widths are overcome naturally. We also provide valuable guidance in searching new heavy-light mesons by the detailed predictions of their masses, widths, and branching ratios. The success of the unquenched quark model presented in this work indicates it may be an important step for understanding the hadron spectrum.

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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.

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arXiv2023

Charmed-strange tetraquarks and their decays in a potential quark model

In the framework of a nonrelativistic potential quark model, we investigate the mass spectrum of the $1S$-wave charmed-strange tetraquark states of $cn\bar{s}\bar{n}$ and $cs\bar{n}\bar{n}$ ($n=u$ or $d$) systems. The tetraquark system is solved by a correlated Gaussian method. With the same parameters fixed by the meson spectra, we obtained the mass spectra for the $1S$-wave tetraquark states. Furthermore, based on the predicted tetraquark spectra we estimate their rearrangement decays in a quark-exchange model. We find that the rearrangement decays of the tetraquarks may be mainly driven by the spin-spin interactions. The resonances $X_0(2900)^0$ and $T^a_{c\bar{s}0}(2900)^{++/0}$ reported from LHCb may be assigned to be the lowest $1S$-wave tetraquark states $\bar{T}_{cs0}^f(2818)$ and $T^{a}_{c\bar{s}0}(2828)$ classified in the quark model, respectively. It also allows us to extract the couplings for the initial tetraquark states to their nearby $S$-wave interaction channels. We find that some of these couplings turn out to be sizeable. Following the picture of the wavefunction renormalization for the near-threshold strong $S$-wave interactions, the sizeable coupling strengths can be regarded as an indication of their dynamic origins as candidates for hadronic molecules. Furthermore, our predictions suggest that signals for the $1S$-wave charmed-strange tetraquark states can also be searched in the other channels, such as $D^0K^+$, $D^+K^+$, $D^{*+}K^-$, $D^{*+}K^+$, $D^{*0}K^+$, $D^0\bar{K}^{*0}$, $D_s^+ρ^0$, etc.

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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.

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arXiv2022

Further understanding the nature of $Ω(2012)$ within a chiral quark model

In our previous works, we have analyzed the two-body strong decays of the low-lying $Ω$ baryon states within a chiral quark model. The results show that the $Ω(2012)$ resonance favors the three-quark state with $J^P=3/2^-$ classified in the quark model. With this assignment, in the present work we further study the three-body strong decay $Ω(2012)\to Ξ^*(1530)\bar{K} \to Ξπ\bar{K}$ and coupled-channel effects on $Ω(2012)$ from nearby channels $Ξ\bar{K}$, $Ωη$ and $Ξ^*(1530)\bar{K}$ within the chiral quark model as well. It is found that the $Ω(2012)$ resonance has a sizeable decay rate into the three-body final state $Ξπ\bar{K}$. The predicted ratio $R_{Ξ\bar{K}}^{Ξπ\bar{K}}=\mathcal{B}[Ω(2012)\to Ξ^*(1530)\bar{K}\to Ξπ\bar{K}]/\mathcal{B}[Ω(2012)\to Ξ\bar{K}]\simeq 12\%$ is close to the up limit $11\%$ measured by the Belle Collaboration in 2019, however, our predicted ratio is too small to be comparable with the recent data $0.97\pm 0.31$. Furthermore, our results show that the coupled-channel effects on the $Ω(2012)$ is not large, its components should be dominated by the bare three-quark state, while the proportion of the molecular components is only $\sim 16\%$. To clarify the nature of $Ω(2012)$, the ratio $R_{Ξ\bar{K}}^{Ξπ\bar{K}}$ is expected to be tested by other experiments.

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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.

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arXiv2022

Toward establishing the low-lying $P$-wave excited $Σ_c$ baryon states

In this study, by combining the equal spacing rule with recent observations of $Ω_c(X)$ and $Ξ_c(X)$ baryons, we predict the spectrum of the low-lying $λ$-mode $1P$-wave excited $Σ_c$ states. Furthermore, their strong decay properties are predicted using the chiral quark model and the nature of $Σ_c(2800)$ is investigated by analyzing the $Λ_cπ$ invariant mass spectrum. The $Σ_c(2800)$ structure observed in the $Λ_c π$ mass spectrum was found to potentially arise from two overlapping $P$-wave $Σ_c$ resonances, $Σ_c(2813)3/2^-$ and $Σ_c(2840)5/2^-$. These resonances have similar decay widths of $Γ\sim 40$ MeV and predominantly decay into the $Λ_c π$ channel. The $Σ_c(2755)1/2^-$ state is likely to be a very narrow state with a width of $Γ\sim 15$ MeV, with its decays almost saturated by the $Λ_c π$ channel. Additionally, evidence of the $Σ_c(2755)\frac{1}{2}^-$ resonance as a very narrow peak may be seen in the $Λ_cπ$ invariant mass spectrum. The other two $P$-wave states, $Σ_c(2746)\frac{1}{2}^-$ and $Σ_c(2796)\frac{3}{2}^-$, are relatively narrow states with similar widths of $Γ\sim 30$ MeV and predominantly decay into $Σ_cπ$ and $Σ^{*}_cπ$, respectively. We hope our study can provide useful references for discovering these low-lying $P$-wave states in forthcoming experiments.

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arXiv2022

Mass spectra and strong decays of charmed and charmed-strange mesons

A semi-relativistic potential model is adopted to calculate the mass spectra of charmed and charmed-strange meson states up to the $2D$ excitations.The strong decay properties are further analyzed with a chiral quark model by using the numerical wave functions obtained from the potential model. By using the strong decay amplitudes extracted from the chiral quark model, we also systematically study the coupled-channel effects on the bare masses of the $1P$-wave states, since the masses of $D^*_{s0}(2317)$ and $D_{s1}(2460)$ cannot be explained with bare $1P$-wave states within the potential model. Based on our good descriptions of the mass and decay properties for the low-lying well-established states, we give a quark model classification for the high mass resonances observed in recent years. In the $D$-meson family, $D_0(2550)$ can be classified as the radially excited state $D(2^1S_0)$; $D_3^*(2750)$ and $D_2(2740)$ can be classified as the second orbital excitations $D(1^3D_3)$ and $D(1D'_2)$, respectively; $D_J^*(3000)$ may be a candidate of $D(1^3F_4)$ or $D(2^3P_2)$; while $D_J(3000)$ may favor the high mass mixed state $D(2P'_1)$; however, there still exist puzzles for understanding the natures of $D_1^*(2600)$ and $D_1^*(2760)$, whose decay properties cannot be well explained with either pure $D(2^3S_1)$ and $D(1^3D_1)$ states or their mixing. In the $D_s$-meson family, $D_{s3}^*(2860)$ favors the $D_s(1^3D_3)$ assignment; $D_{s1}^*(2700)$ and $D_{s1}^*(2860)$ may favor the mixed states $|(SD)_1\rangle_L$ and $|(SD)_1\rangle_H$ via the $2^3S_1$-$1^3D_1$ mixing, respectively; $D_{sJ}(3040)$ may favor $D_s(2P_1)$ or $D_s(2P_1')$, or corresponds to a structure contributed by both $D_s(2P_1)$ and $D_s(2P_1')$.

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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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arXiv2021

Higher mass spectra of the fully-charmed and fully-bottom tetraquarks

In this work, we calculate the higher mass spectra for the $2S$- and $1D$-wave fully-charmed and fully-bottom tetraquark states in a nonrelativistic potential quark model. The $2S$-wave fully-charmed/bottom tetraquark states lie in the mass range of $\sim (6.9,7.1)$/$(19.7,19.9)$ GeV, apart for the highest $0^{++}$ state $T_{(cc\bar{c}\bar{c})0^{++}}(7185)$/ $T_{(bb\bar{b}\bar{b})0^{++}}(19976)$. Most of the $2S$-wave states highly overlap with the high-lying $1P$-wave states. The masses for the $1D$-wave fully-charmed/bottom tetraquarks are predicted to be in the range of $\sim (6.7,7.2)/(19.5,20.0)$ GeV. The mass range for the $D$-wave tetraquark states cover most of the mass range of the $P$-wave states and the whole mass range of the $2S$-wave states. The narrow structure $X(6900)$ recently observed at LHCb in the di-$J/ψ$ invariant mass spectrum may be caused by the $1P$-, or $2S$-, or $1D$-wave $T_{cc\bar{c}\bar{c}}$ states. The vague structure $X(7200)$ may be caused by the highest $2S$-wave state $T_{(cc\bar{c}\bar{c})0^{++}}(7185)$, two low-lying $3S$-wave states $T_{(cc\bar{c}\bar{c})0^{++}}(7240)$ and $T_{(cc\bar{c}\bar{c})2^{++}}(7248)$, and/or the high-lying $1D$-wave states with masses around 7.2 GeV and $J^{PC}=0^{++},1^{++},2^{++},3^{++}$, or $4^{++}$. While it is apparent that the potential quark model calculations predict more states than the structures observed in the di-$J/ψ$ invariant mass spectrum, our calculations will help further understanding of the properties of these fully-heavy tetraquark states in their strong and magnetic interactions with open channels based on explicit quark model wave functions.

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arXiv2021

Nature of $X(6900)$ and its production mechanism at LHCb

We show that the Pomeron exchanges play a unique role in vector charmonium scatterings. Such a mechanism can provide a natural explanation for the nontrivial structures in the di-$J/ψ$ spectrum observed by the LHCb Collaboration. The narrow structure $X(6900)$, as a dynamically generated resonance pole, can arise from the Pomeron exchanges and coupled-channel effects between the $J/ψ$-$J/ψ$, $J/ψ$-$ψ(2S)$ scatterings. A pole structure near the di-$J/ψ$ threshold is also found. Meanwhile, we predict that $X(6900)$ can produce significant threshold enhancement in the $J/ψ$-$ψ(2S)$ energy spectrum which can be searched for at LHCb.

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arXiv2021

Fully-strange tetraquark $ss\bar{s}\bar{s}$ spectrum and possible experimental evidence

In this work we construct 36 tetraquark configurations for the $1S$-, $1P$-, and $2S$-wave states, and make a prediction of the mass spectrum for the tetraquark $ss\bar{s}\bar{s}$ system in the framework of a nonrelativistic potential quark model without the diquark-antidiquark approximation. The model parameters are well determined by our previous study of the strangeonium spectrum. We find that the resonances $f_0(2200)$ and $f_2(2340)$ may favor the assignments of ground states $T_{(ss\bar{s}\bar{s})0^{++}}(2218)$ and $T_{(ss\bar{s}\bar{s})2^{++}}(2378)$, respectively, and the newly observed $X(2500)$ at BESIII may be a candidate of the lowest mass $1P$-wave $0^{-+}$ state $T_{(ss\bar{s}\bar{s})0^{-+}}(2481)$. Signals for the other $0^{++}$ ground state $T_{(ss\bar{s}\bar{s})0^{++}}(2440)$ may also have been observed in the $ϕϕ$ invariant mass spectrum in $J/ψ\toγϕϕ$ at BESIII. The masses of the $J^{PC}=1^{--}$ $T_{ss\bar{s}\bar{s}}$ states are predicted to be in the range of $\sim 2.44-2.99$ GeV, which indicates that the $ϕ(2170)$ resonance may not be a good candidate of the $T_{ss\bar{s}\bar{s}}$ state. This study may provide a useful guidance for searching for the $T_{ss\bar{s}\bar{s}}$ states in experiments.

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arXiv2021

Mass spectrum and strong decays of strangeonium in a constituent quark model

In this work we calculate the mass spectrum of strangeonium up to the $3D$ multiplet within a nonrelativistic linear potential quark model. Furthermore, using the obtained wave functions, we also evaluate the strong decays of the strangeonium states with the $^3P_0$ model. Based on our successful explanations of the well established states $ϕ(1020)$, $ϕ(1680)$, $h_1(1415)$, $f'_2(1525)$, and $ϕ_3(1850)$, we further discuss the possible assignments of strangeonium-like states from experiments by combining our theoretical results with the observations. It is found that some resonances, such as $f_2(2010)$ and $f_2(2150)$ listed by the Particle Data Group, and $X(2062)$ and $X(2500)$ newly observed by BESIII, may be interpreted as the strangeonium states. The possibility of $ϕ(2170)$ as a candidate for $ϕ(3S)$ or $ϕ(2D)$ cannot be excluded. We expect our results to provide useful references for looking for the missing $s\bar{s}$ states in future experiments.

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arXiv2021

Towards establishing an abundant $B$ and $B_s$ spectrum up to the second orbital excitations

Stimulated by the exciting progress in experiments, we carry out a combined analysis of the masses, and strong and radiative decay properties of the $B$ and $B_s$-meson states up to the second orbital excitations. Based on our good descriptions of the mass and decay properties for the low-lying well-established states $B_1(5721)$, $B_2^*(5747)$, $B_{s1}(5830)$ and $B_{s2}^*(5840)$, we give a quark model classification for the high mass resonances observed in recent years. It is found that (i) the $B_{J}(5840)$ resonance may be explained as the low mass mixed state $B(|SD\rangle_L)$ via $2^3S_1$-$1^3D_1$ mixing, or the pure $B(2^3S_1)$ state, or $B(2^1S_0)$. (ii) The $B_J(5970)$ resonance may be assigned as the $1^3D_3$ state in the $B$ meson family, although it as a pure $2^3S_1$ state cannot be excluded. (iii) The narrow structure around 6064 MeV observed in the $B^+K^-$ mass spectrum at LHCb may be mainly caused by the $B_{sJ}(6109)$ resonance decaying into $B^{*+}K^-$, and favors the assignment of the high mass $1D$-wave mixed state $B_s(1D'_2)$ with $J^P=2^-$, although it as the $1^3D_3$ state cannot be excluded. (iv) The relatively broader $B_{sJ}(6114)$ structure observed at LHCb may be explained with the mixed state $B_s(|SD\rangle_H)$ via $2^3S_1$-$1^3D_1$ mixing, or a pure $1^3D_1$ state. Most of the missing $1P$-, $1D$-, and $2S$-wave $B$- and $B_s$-meson states have a relatively narrow width, they are most likely to be observed in their dominant decay channels with a larger data sample at LHCb.

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arXiv2020

Toward establishing the low-lying $P$-wave $Σ_b$ states

In the present work, we analyze the $P$-wave singly-heavy baryon spectrum belonging to $\mathbf{6}_F$ by combining the observations of the heavy baryon states, and restudy the strong decays of the $1P$ wave $Σ_b$ states within the $j$-$j$ coupling scheme using the chiral quark model. We obtain that: (i) the structure $Σ_b(6097)$ observed in the $Λ_bπ$ final state may arise from the overlapping of $Σ_b|J^P=\frac{3}{2}^-,2\rangle$ and $Σ_b|J^P=\frac{5}{2}^-,2\rangle$. (ii) The broad structure $Σ_b(6072)$ observed in the $Λ_bππ$ final state may arise from the overlapping of $Σ_b|J^P=\frac{1}{2}^-,1\rangle$ and $Σ_b|J^P=\frac{3}{2}^-,1\rangle$. (iii) The missing state $Σ_b|J^P=\frac{1}{2}^-,0\rangle$ is most likely to be a narrow state with a width of $Γ\sim10$ MeV, and mainly decays into $Λ_bπ$ channel.

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arXiv2020

Understanding the newly observed $Ξ_c^0$ states through their decays

Inspired by the newly observed $Ξ_c^0$ states by the LHCb Collaboration, we investigate the OZI-allowed two-body strong decays of the $λ$-mode $1P$ wave $Ξ'_c$ states within the chiral quark model. Our results indicate that: (i) the newly observed states $Ξ_c(2923)^0$ and $Ξ_c(2939)^0$ are good candidates of the $λ$-mode $1P$ wave $Ξ'_c$ states with the spin-parity $J^P=3/2^-$, namely $|^4P_λ3/2^-\rangle$ and $|^2P_λ3/2^-\rangle$, respectively. (ii) The another newly observed state $Ξ_c(2965)^0$ mostly corresponds to the $λ$-mode $1P$-wave $Ξ'_c$ state with the spin-parity $J^P=5/2^-$, namely $|^4P_λ5/2^-\rangle$. (iii) For the two $λ$-mode $J^P=1/2^-$ mixed states, the $|P_λ~1/2^-\rangle_1$ is a narrow state with a width of $Γ\sim15$ MeV and mainly decays into $Ξ'_cπ$; while the $|P_λ~1/2^-\rangle_2$ state has a width of $Γ\sim52$ MeV and dominantly decays into $Ξ_cπ$ and $Λ_cK$ channels. If the broad structure around $2880$ MeV observed at LHCb arises from the new $Ξ^0_c$ state, this state is very likely to be the $|P_λ~1/2^-\rangle_2$ state.

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arXiv2020

Possible interpretation of the newly observed $Ω_b$ states

Inspired by the newly observed $Ω_b$ states by the LHCb Collaboration, we investigate the two-body strong decays of the low-lying $λ$-mode $Ω_b$ baryons up to $N=2$ shell using the chiral quark model within the $j$-$j$ coupling scheme. Our results indicate that: (i) the newly observed states $Ω_b(6316)^-$ and $Ω_b(6330)^-$ are good candidates of the light spin $j=1$ states, while the spin-parity $J^P=1/2^-$ and $J^P=3/2^-$ cannot be distinguished. The other two states, $Ω_b(6340)$ and $Ω_b(6350)$ mostly correspond to the light spin $j=2$ states, while the spin-parity $J^P=3/2^-$ and $J^P=5/2^-$ cannot be distinguished as well.(ii) The $2S$ states with spin-parity $J^P=1/2^+$ and $J^P=3/2^+$, respectively, might be narrow states with a width of $Γ<2$ MeV. (iii) The $1D$ states are not broad and the total decay widths vary from several to dozens of MeV, which have a good potential to be observed in future experiments.

hep-ph↗