arXiv subjects

Xian-Hui Zhong

Publications and source records attributed to Xian-Hui Zhong.

At least 55 records · Page 3Linked to original sources

arXiv2020

All-heavy tetraquarks

In this work we study the mass spectra of the fully-heavy tetraquark systems, i.e. $cc\bar{c}\bar{c}$, $bb\bar{b}\bar{b}$, $bb\bar{c}\bar{c}/cc\bar{b}\bar{b}$, $bc\bar{c}\bar{c}/cc\bar{b}\bar{c}$, $bc\bar{b}\bar{b}/bb\bar{b}\bar{c}$, and $bc\bar{b}\bar{c}$, within a potential model by including the linear confining potential, Coulomb potential, and spin-spin interactions. It shows that the linear confining potential has important contributions to the masses and is crucial for our understanding of the mass spectra of the fully-heavy tetraquark systems. For the fully-heavy tetraquarks $Q_1Q_2\bar{Q}_3\bar{Q}_4$ our explicit calculations suggest that no bound states can be formed below the thresholds of any meson pairs $(Q_1\bar{Q}_3)$-$(Q_2\bar{Q}_4)$ or $(Q_1\bar{Q}_4)$-$(Q_2\bar{Q}_3)$. Thus, we do not expect narrow fully-heavy tetraquark states to be existing in experiments.

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arXiv2020

Strong decays of the higher excited $Λ_Q$ and $Σ_Q$ baryons

In this work, we preform a systematic study of the strong decays for the higher singly heavy baryon resonances $Λ_Q(3S)$, $Λ_Q(2P)$, $Λ_Q(2D)$, $Λ_Q(1F)$, $Σ_Q(3S)$, $Σ_Q(2P)$, $Σ_Q(2D)$, and $Σ_Q(1F)$ within the $^3P_0$ model. Our results show that most of the $λ-$mode higher excited $Λ_Q$ and $Σ_Q$ states have a relatively narrow width, and mainly decay into two-body final states with one heavy meson plus one light baryon. Our calculations provide abundant theoretical information and demonstrate the general feature for these higher states, which may be valuable for future experimental searches and establishing the singly heavy baryon spectrum.

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arXiv2019

Triply charmed and bottom baryons in a constituent quark model

In this work, we study the mass spectrum of the $Ω_{ccc}$ and $Ω_{bbb}$ baryons up to the $N=2$ shell within a nonrelativistic constituent quark model (NRCQM). The model parameters are adopted from the determinations by fitting the charmonium and bottomonium spectra in our previous works. The masses of the $Ω_{ccc}$ and $Ω_{bbb}$ baryon states predicted in present work reasonably agree with the results obtained with the Lattice QCD calculations. Furthermore, to provide more knowledge of the $Ω_{ccc}$ and $Ω_{bbb}$ states, we evaluate their radiative decays with the available masses and wave functions from the potential model.

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arXiv2019

$Ω$ baryon spectrum and their decays in a constituent quark model

Combining the recent developments of the observations of $Ω$ sates we calculate the $Ω$ spectrum up to the $N=2$ shell within a nonrelativistic constituent quark potential model. Furthermore, the strong and radiative decay properties for the $Ω$ resonances within the $N=2$ shell are evaluated by using the masses and wave functions obtained from the potential model. It is found that the newly observed $Ω(2012)$ resonance is most likely to be the spin-parity $J^P=3/2^-$ $1P$-wave state $Ω(1^{2}P_{3/2^{-}})$, it also has a large potential to be observed in the $Ω(1672)γ$ channel. Our calculation shows that the 1$P$-, 1$D$-, and 2$S$-wave $Ω$ baryons have a relatively narrow decay width of less than 50 MeV. Based on the obtained decay properties and mass spectrum, we further suggest optimum channels and mass regions to find the missing $Ω$ resonances via the strong and/or radiative decay processes.

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arXiv2019

A possible explanation of the threshold enhancement in the process $e^+e^-\rightarrow Λ\barΛ$

Inspired by the recent measurement of the process $e^+e^-\rightarrow Λ\barΛ$, we calculate the mass spectrum of the $ϕ$ meson with the GI model. For the excited vector strangeonium states $ϕ(3S,~4S,~5S,~6S)$ and $ϕ(2D,~3D,~4D,~5D)$, we further investigate the electronic decay width with the Van Royen-Weisskopf formula, and the partial widths of the $Λ\barΛ$, $Ξ^{-(*)}\barΞ^+$, and $Σ^{+(*)}\barΣ^{-(*)}$ decay modes with the extended quark pair creation model. We find that the electronic decay width of the $D$-wave vector strangeonium is about $3\sim8$ times larger than that of the $S$-wave vector strangeonium. Around 2232 MeV the partial decay width of the $Λ\barΛ$ mode can reach up to several MeV for $ϕ(3^3S_1)$, while the partial $Λ\barΛ$ decay width of $ϕ(2^3D_1)$ is $\mathcal{O}(10^{-3})$ keV. If the threshold enhancement reported by the BESIII Collaboration arises from the strangeonium meson, this state is very likely to be the $ϕ(3^3S_1)$ state. We also note that the $Λ\barΛ$ and $Σ^{+}\barΣ^{-}$ partial decay widths of the states $ϕ(3^3D_1)$ and $ϕ(4^3S_1)$ are about several MeV, respectively, which are enough to be observed in future experiments.

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arXiv2019

Interpretation of the newly observed $Λ_b(6146)^{0}$ and $Λ_b(6152)^0$ states in a chiral quark model

The strong decays of the low-lying $λ$-mode $Λ_b(1D,2S)$ and $Σ_b(2S)$ states are studied in a chiral quark model. We find that: (i) the newly observed $Λ_b(6146/6152)$ resonances in the $Λ_bπ^+π^-$ spectrum by the LHCb Collaboration might be explained with the $λ$-mode $Λ_b(1D)$ states in the quark model. It should be emphasized that whether the structure in the $Λ_bπ^+π^-$ spectrum correspond to two states or one state should be further clarified with more observations in future experiments. (ii) The $Λ_b(2S)$ $|J^P = \frac{1}{2}^+,0\rangle$ state mainly decays into $Σ_b^*π$ channel, which may be an ideal channel for searching for this $Λ_b(2S)$ state in future experiments. (iii) The $Σ_b(2S)$ $|J^P = \frac{1}{2}^+,1 \rangle$ and $|J^P = \frac{3}{2}^+,1 \rangle$ dominantly decay into $Λ_bπ$ with $Γ\simeq 3.82$ MeV and $Γ\simeq 4.72$ MeV, respectively.

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arXiv2019

Canonical interpretation of the newly observed $Λ_b(6146)^0$ and $Λ_b(6152)^0$ via strong decay behaviors

Stimulated by the newly observed $Λ_b(6146)^0$ and $Λ_b(6152)^0$ resonances, we investigate the strong decays of the low-lying singly bottom baryons within the quark pair creation model. Considering their masses and decay modes, we tentatively assign these states as the $λ-$ mode $Λ_b(2S)$, $Λ_b(1D)$, $Σ_b(2S)$, and $Σ_b(1P)$ states, and then estimate their strong decay widths. Compared with the experimental total widths and decay modes measured by the LHCb Collaboration, the $Λ_b(6146)^0$ and $Λ_b(6152)^0$ can be reasonably clarified into the $J^P=5/2^+$ and $J^P=3/2^+$ $Λ_b(1D)$ sates respectively, while other canonical assignments are disfavored. Other low-lying bottom states are also presented, where various narrow states may have good potential to be observed in future LHCb experiments.

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arXiv2019

Canonical interpretation of $Y(10750)$ and $Υ(10860)$ in the $Υ$ family

Inspired by the new resonance $Y(10750)$, we calculate the masses and two-body OZI-allowed strong decays of the higher vector bottomonium sates within both screened and linear potential models. We discuss the possibilities of $Υ(10860)$ and $Y(10750)$ as mixed states via the $S-D$ mixing. Our results suggest that $Y(10750)$ and $Υ(10860)$ might be explained as mixed states between $5S$- and $4D$-wave vector $b\bar{b}$ states. The $Y(10750)$ and $Υ(10860)$ resonances may correspond to the mixed states dominated by the $4D$- and $5S$-wave components, respectively. The mass and the strong decay behaviors of the $Υ(11020)$ resonance are consistent with the assignment of the $Υ(6S)$ state in the potential models.

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arXiv2019

The excited bottom-charmed mesons in a nonrelativistic quark model

Using the newly measured masses of $B_c(1S)$ and $B_c(2S)$ from the CMS Collaboration and the $1S$ hyperfine splitting determined from the lattice QCD as constrains, we calculate the $B_c$ mass spectrum up to the $6S$ multiplet with a nonrelativistic linear potential model. Furthermore, using the wave functions from this model we calculate the radiative transitions between the $B_c$ states within a constituent quark model. For the higher mass $B_c$ states lying above $DB$ threshold, we also evaluate the Okubo-Zweig-Iizuka (OZI) allowed two-body strong decays with the $^{3}P_{0}$ model. Our study indicates that besides there are large potentials for the observations of the low-lying $B_c$ states below the $DB$ threshold via their radiative transitions, some higher mass $B_c$ states, such as $B_c(2^3P_2)$, $B_c(2^3D_1)$, $B_c(3^3D_1)$, $B_c(4^3P_0)$, and the $1F$-wave $B_c$ states, might be first observed in their dominant strong decay channels $DB$, $DB^*$ or $D^*B$ at the LHC for their relatively narrow widths.

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arXiv2018

Interpretation of the newly observed $Σ_b(6097)^{\pm}$ and $Ξ_b(6227)^-$ states as the $P$-wave bottom baryons

The strong decays of the $P$-wave $Σ_b$, $Ξ_b'$ and $Ω_b$ baryons are investigated with a constituent quark model in the $j$-$j$ coupling scheme. The results show that the newly observed $Σ_b(6097)$ and $Ξ_b(6227)$ states by the LHCb collaboration can be assigned as the $λ$-mode $P$-wave singly bottom baryons. Given the heavy quark symmetry, both the $Σ_b(6097)$ and $Ξ_b(6227)$ states favor the light spin $j=2$ states with spin-parity numbers $J^P=3/2^-$ or $J^P=5/2^-$. More $P$-wave singly bottom baryons are most likely to be observed in future experiments for their relatively narrow width.

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arXiv2018

Strong and radiative decays of the low-lying $D$-wave singly heavy baryons

The strong and radiative decays of the low-lying $λ$-mode $D$-wave $Λ_{c(b)}$, $Σ_{c(b)}$, $Ξ_{c(b)}$, $Ξ_{c(b)}'$, and $Ω_{c(b)}$ baryons are studied in a constituent quark model. Our calculation shows the following: (i) The missing $λ$-mode $D$-wave $Ω_{c(b)}$, $Λ_{b}$, and $Ξ_{b}$ baryons have a relatively narrow decay width of a few MeV or a few tens of MeV and their dominant strong and radiative decay channels can be ideal for searching for their signals in future experiments. (ii) The $λ$-mode $1D$-wave excitations in the $Σ_{c(b)}$ and $Ξ_{c(b)}'$ families appear to have a relatively broad width of $\sim 50-200$ MeV.Most of the $1D$-wave states have large decay rates into the $1P$-wave heavy baryons via the pionic or kaonic strong decay processes, which should be taken seriously in future observations. (iii) Both $Λ_c(2860)$ and $Ξ_c(3050)$ seem to favor the $J^P=3/2^+$ excitation $|^2D_{λλ} \frac{3}{2}^+ \rangle$ of $\bar{\mathbf{3}}_F$, while both $Λ_c(2880)$ and $Ξ_c(3080)$ may be assigned as the $J^P=5/2^+$ excitation $|^2D_{λλ} \frac{5}{2}^+ \rangle$ of $\bar{\mathbf{3}}_F$. The nature of $Ξ_c(3050)$ and $Ξ_c(3080)$ could be tested by the radiative transitions $Ξ_c(3055)^0\to Ξ_c(2790)^0 γ$ and $Ξ_c(3080)^0 \to Ξ_c(2815)^0 γ$, respectively.

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arXiv2018

Newly observed $Ω(2012)$ state and strong decays of the low-lying $Ω$ excitations

Stimulated by the newly discovered $Ω(2012)$ resonance at Belle II, in this work we have studied the OZI allowed strong decays of the low-lying $1P$- and $1D$-wave $Ω$ baryons within the $^3P_0$ model. It is found that $Ω(2012)$ is most likely to be a $1P$-wave $Ω$ state with $J^P=3/2^-$. We also find that the $Ω(2250)$ state could be assigned as a $1D$-wave state with $J^P=5/2^+$. The other missing $1P$- and $1D$-wave $Ω$ baryons may have large potentials to be observed in their main decay channels.

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arXiv2018

Strong decays of higher charmonium states into open-charm meson pairs

The open-charm strong decays of higher charmonium states up to the mass of the $6P$ multiplet are systematically studied in the $^3P_0$ model. The wave functions of the initial charmonium states are calculated in the linear potential (LP) and screened potential (SP) quark model. The decay widths for most of the well-established charmonium states above the open-charm thresholds can be reasonably described. By comparing our quark model calculations with the experimental observations we also discuss the nature of some of the newly observed charmonium-like states. It is found that (i) the $ψ(4415)$ may favor the $ψ(4S)$ or $ψ_1(3D)$ assignment. There may exist two highly overlapping vector charmonium states around 4.4 GeV; (ii) In the LP model the $J^{PC}=1^{--}$ $Y(4660)$ resonance and the $J^{PC}=0^{++}$ $X(4500)$ resonance may be assigned as the $ψ(5S)$ and $χ_{c0}(4P)$, respectively; (iii) The newly observed state $X^*(3860)$ can be assigned as the $χ_{c0}(2P)$ state with a narrow width of about $30$ MeV; (iv) It seems to be difficult to accommodate the $X(4140)$ and $X(4274)$ states in the same potential model as excited $χ_{c1}$ states. (v) The $X(3940)$ resonance can be assigned as the $η_c(3S)$ state; (vi) The vector charmonium-like states $Y(4230/4260,4360)$ and scalar $X(4700)$ cannot be described by any conventional charmonium states self-consistently in our model.

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arXiv2018

Strong decay of $Λ_c(2940)$ as a $2P$ state in the $Λ_c$ family

Considering the mass, parity and $D^0 p$ decay mode, we tentatively assign the $Λ_c(2940)$ as the $P-$wave states with one radial excitation. Then, via studying the strong decay behavior of the $Λ_c(2940)$ within the $^3P_0$ model, we obtain that the total decay widths of the $Λ_{c1}(\frac{1}{2}^-,2P)$ and $Λ_{c1}(\frac{3}{2}^-,2P)$ states are 16.27 MeV and 25.39 MeV, respectively. Compared with the experimental total width $27.7^{+8.2}_{-6.0}\pm0.9^{+5.2}_{-10.4}~\rm{MeV}$ measured by LHCb Collaboration, both assignments are allowed, and the $J^P=\frac{3}{2}^-$ assignment is more favorable. Other $λ-$mode $Σ_c(2P)$ states are also investigated, which are most likely to be narrow states and have good potential to be observed in future experiments.

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arXiv2018

A possible interpretation of the newly observed $Ω(2012)$ state

Inspired by the newly observed $Ω(2012)$ state at Belle II, we investigate the two-body strong decays of $Ω$ baryons up to $N=2$ shell within the chiral quark model. Our results indicate that: (i) the newly observed $Ω(2012)$ state could be assigned to the spin-parity $J^P=3/2^-$ state $|70,^210,1,1,\frac{3}{2}^-\rangle$ and the experimental data can be reasonably described. However, the spin-parity $J^P=1/2^-$ state $|70,^210,1,1,\frac{1}{2}^-\rangle$ and spin-parity $J^P=3/2^+$ state $|56,^410,2,0,\frac{3}{2}^+\rangle$ can't be completely excluded. (ii) The $D$-wave states in the $N=2$ shell are most likely to be narrow states with a width of dozens of MeV and have a good potential to be observed in the $ΞK$ and/or $Ξ(1530)K$ channels in future experiments. The $Ω(2250)$ resonance listed in PDG may be a good candidate of the $J^P=5/2^+$ $1D$ wave state $|56,^410,2,2,5/2^+\rangle$.

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arXiv2018

A new decay mode of higher charmonium

We calculate the $Λ_c\barΛ_c$ partial decay width of the excited vector charmonium states around 4.6 GeV with the quark pair creation model. We find that the partial decay width of the $Λ_c\barΛ_c$ mode can reach up to several MeV for $ψ(4S,~5S,~6S)$. In contrast, the partial $Λ_c\barΛ_c$ decay width of the states $ψ(3D,~4D,~5D)$ is less than one MeV. If the enhancement $Y(4630)$ reported by the Belle Collaboration in $Λ_c\barΛ_c$ invariant-mass distribution is the same structure as $Y(4660)$, the $Y(4660)$ resonance is most likely to be a $S$-wave charmonium state.

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arXiv2018

Revisiting the pseudoscalar meson and glueball mixing and key issues in the search for pseudscalar glueball state

We revisit the mixing mechanism for pesudscalar mesons and glueball which is introduced by the axial vector anomaly. We demonstrate that the physical mass of the pseudoscalar glueball does not favor to be lower than 1.8 GeV if all the parameters are reasonably constrained. This conclusion, on the one hand, can accommodate the pseudoscalar glueball mass calculated by Lattice QCD, and on the other hand, is consistent with the high-statistics analyses at BESIII that all the available measurements do not support the presence of two closely overlapping pseudoscalar states in any exclusive channel. Such a result is in agreement with the recent claim that the slightly shifted peak positions for two possible states $η(1405)$ and $η(1475)$ observed in different channels are actually originated from one single state with the triangle singularity interferences. By resolving this long-standing paradox, one should pay more attention to higher mass region for the purpose of searching for the pseudoscalar glueball candidate.

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arXiv2018

Strong and radiative decays of the low-lying $S$- and $P$-wave singly heavy baryons

The strong and radiative decays of the low-lying $S$- and $P$-wave $Λ_{c(b)}$, $Σ_{c(b)}$, $Ξ_{c(b)}$, $Ξ_{c(b)}'$ and $Ω_{c(b)}$ baryons are systematically studied in a constituent quark model. We find that the radiative decay mode $Λ_b^0γ$ could be very useful for us to establish the missing neutral states $Σ_b^{0}$ and $Σ_b^{*0}$. Our calculation shows that most of those missing $λ$-mode $P$-wave singly heavy baryons have relatively narrow decay width of less than 30 MeV. Their dominant strong and radiative decay channels can be ideal for searching for their signals in future experiment. Configuration mixings between the $J^P=1/2^-$ states $|^2P_λ \frac{1}{2}^- \rangle$ and $|^4P_λ \frac{1}{2}^- \rangle$ of the $\mathbf{6}_F$ multiplet are discussed. The $Ξ_c(2930)^0$ state seems to favor the mixed state $|Ξ_c'~ P_λ\frac{1}{2}^-\rangle_2$ with $J^P=1/2^-$. The $Σ_c(2800)$ resonance may be assigned to $|Σ_c~ ^2P_λ \frac{3}{2}^- \rangle$ with $J^P=3/2^-$ or $|Σ_c~ ^4P_λ \frac{5}{2}^- \rangle$ with $J^P=5/2^-$. In general, the excitations of $|^2P_λ \frac{3}{2}^- \rangle$ and $|^4P_λ \frac{5}{2}^- \rangle$ of the $\mathbf{6}_F$ multiplet have similar strong decay properties. In order to to identify them, angular distributions of their decays in either strong decay modes or radiative transitions should be needed.

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