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.
In consistency with the b --> c type of (quasi) two body decays, recently observed two body decays of B mesons are studied in a hybrid perspective in which their amplitude is given by a sum of factorizable and non-factorizable ones, and a role of the latter in these decays are discussed.
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.
Very recently, a new $Ω^{*}$ state was reported by the Belle Collaboration, with its mass of $2012.4 \pm 0.7\ \text{(stat)}\pm 0.6\ \text{(syst)}\ \mathrm{MeV}$, which locates just below the $KΞ^*$ threshold and hence hints to be a possible $KΞ^*$ hadronic molecule. Using the effective Lagrangian approach as the same as our previous works for other possible hadronic molecular states, we investigate the decay behavior of this new $Ω^*$ state within the hadronic molecular picture. The results show that the measured decay width can be reproduced well and its dominant decay channel is predicted to…
Basing on the observation of a new $J^{PC}=0^{-+}$ state, $X(2500)$, in the partial wave analysis of the decay $J/ψ\rightarrowγX\rightarrow γϕϕ$ performed by the BESIII Collaboration, we have evaluated the strong decays of the $X(2500)$ as the $4^1S_0$ and $5^1S_0$ $s\bar{s}$ states in the $^3P_0$ meson decay model. The predicted total decay width for the $4^1S_0$ $s\bar{s}$ is about 894.5 MeV, and the one for the $5^1S_0$ $s\bar{s}$ is about 271.1 MeV, which is in agreement with the experimental data $Γ_{X(2500)}=230^{+64+56}_{-35-33}$ MeV. By considering the mass and the total strong decay w…
In our former work [arXiv:2011.07214], the $P_{cs}(4459)$ observed by the LHCb Collaboration can be explained as a coupled strange hidden-charm $Ξ_c\bar{D}^*/Ξ_c^*\bar{D}/Ξ_c'\bar{D}^*/Ξ_c^*\bar{D}^*$ molecule with $I(J^P)=0(3/2^-)$. Here, we further discuss the two-body strong decay behaviors of the $P_{cs}(4459)$ in the meson-baryon molecular scenario by input the former obtained bound solutions. Our results support the $P_{cs}(4459)$ as the strange hidden-charm $Ξ_c\bar{D}^*$ molecule with $I(J^P)=0(3/2^-)$. The relative decay ratio between $Λ_cD_s^*$ and $J/ψΛ$ is around 10, where the part…
The strong and radiative decay properties of the low-lying $Ω_c$ states are studied in a constituent quark model. We find that the newly observed $Ω_c$ states by the LHCb Collaboration can fit in well the decay patterns. Thus, their spin-parity can be possibly assigned as the following: (i) The $Ω_c(3000)$ has $J^P=1/2^-$ and corresponds to the narrow $1P$ mixed state $|1^2P_λ\frac{1}{2}^-\rangle_1$, its partner $|1^2P_λ\frac{1}{2}^-\rangle_2$ should be a broad state with a width of $\sim 100$ MeV. (ii) The $Ω_c(3050)$ and $Ω_c(3066)$ can be assigned to be two $J^P=3/2^-$ states, $|1^4P_λ\frac…
The strong decay properties of the newly observed states $D_{sJ}(3040)$, $D_{sJ}(2860)$ and $D_{sJ}(2710)$ are studied in a constituent quark model with quark-meson effective Lagrangians. We find that the $D_{sJ}(3040)$ could be identified as the low mass physical state $|2{P_1}>_L$ ($J^P=1^+$) from the $D_{s}(2^1P_1)$-$D_{s}(2^3P_1)$ mixing. The $D_{sJ}(2710)$ is likely to be the low-mass mixed state $|(SD)>_L$ via the $1^3D_1$-$2^3S_1$ mixing. In our model, the $D_{sJ}(2860)$ cannot be assigned to any single state with a narrow width and compatible partial widths to $DK$ and $D^*K$. Thus, we…
We interprete the new double charm baryon state found by the LHCb Collaboration in the invariant mass distribution of the set of final state particles $(Λ_c^+\,K^-\,π^+\,π^+)$ as being at the origin of the decay chain $Ξ_{cc}^{++} \to Σ_c^{++} (\to Λ_c^+ π^+) +\bar K^{*0} (\to K^- π^+)$. The nonleptonic decay $Ξ_{cc}^{++} \to Σ_c^{++} + \bar K^{*0}$ belongs to a class of decays where the quark flavor composition is such that the decay proceeds solely via the factorizing contribution precluding a contamination from internal $W$-exchange. We use the covariant confined quark model previously deve…
The mass and decay constant of the $X(5568)$ state newly observed by D0 Collaboration are computed within the two-point sum rule method using the diquark-antidiquark interpolating current. In calculations, the vacuum condensates up to eight dimensions are taken into account. The obtained result for the mass of the $X(5568)$ state is in a nice agreement with the experimental data.
In this work, we study strong and radiative decays of S-wave DΞmolecular state, which is related to the Ω^*_c states newly observed at LHCb. The coupling between the DΞmolecular state and its constituents D and Ξis calculated by using the compositeness condition. With the obtained coupling, the partial decay widths of the DΞmolecular state into the Ξ_c^{+}K^{-}, Ξ^{'+}_cK^{-} and Ω^{*}_c(2695)γfinal states through hadronic loop are calculated with the help of the effective Lagrangians. By comparison with the LHCb observation, the current results of total decay width support the Ω^{*}_c(3119) o…
Very recently, the LHCb Collaboration at the Large Hadron Collider at CERN observed new resonance $X(4630)$. The $X(4630)$ is decoded as a charmoniumlike molecule with hidden-strange quantum number well in the one boson exchange mechanism. Especially, the study of its hidden-charmed decays explicitly shows the dominant role of $J/ψϕ$ among all allowed hidden-charmed decays of $X(4630)$, which enforces the conclusion of $X(4630)$ as a charmoniumlike molecule. The discovery of the $X(4630)$ is a crucial step of constructing charmoniumlike molecule zoo.
The strong decay properties of the newly observed $D(2550)$, $D(2600)$, $D(2750)$ and $D(2760)$ are studied in a constituent quark model. It is predicted that the $D(2760)$ and $D(2750)$ seem to be two overlapping resonances. The $D(2760)$ could be identified as the $1^3D_3$ with $J^P=3^-$, while the $D(2750)$ is most likely to be the high-mass mixed state $|1{D_2}'>_H$ ($J^P=2^-$) via the $1^1D_2$-$1^3D_2$ mixing. The $D(2600)$ favors the low-mass mixed state $|(SD)_1>_L$ $(J^P=1^-)$ via the $1^3D_1$-$2^3S_1$ mixing. The $D(2550)$ as the $2^1S_0$ assignment bears controversies for its too bro…
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 m…
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 respec…
Lately, the LHCb Collaboration reported the discovery of two new states in the $B^+\rightarrow D^+D^- K^+$ decay, i.e., $X_0(2866)$ and $X_1(2904)$. In the present work, we study whether these states can be understood as $D^*\bar{K}^*$ molecules from the perspective of their two-body strong decays into $D^-K^+$ via triangle diagrams and three-body decays into $D^*\bar{K}π$. The coupling of the two states to $D^*\bar{K}^*$ are determined from the Weinberg compositeness condition, while the other relevant couplings are well known. The obtained strong decay width for the $X_0(2866)$, in marginal …
Hadronic decay widths of the newly observed charmed strange baryons, $Ω_c(3000)^0$, $Ω_c(3050)^0$, $Ω_c(3066)^0$, $Ω_c(3090)^0$ and $Ω_c(3119)^0$ have been calculated in a $^3P_0$ model. Our results indicate that $Ω_c(3066)^0$ and $Ω_c(3090)^0$ can be interpreted as the $1P-$wave $Ω_{c2}(\frac{3}{2}^-)$ or $Ω_{c2}(\frac{5}{2}^-)$. Though the measured masses of $Ω_c(3000)^0$, $Ω_c(3050)^0$ and $Ω_c(3119)^0$ are lower than existed theoretical predictions of $1D-$wave $Ω_c$, the hadronic decay features of these $Ω_c$ favor assignments of the $1D-$wave states. $Ω_c(3000)^0$ is possibly $Ω_{c1}(\fr…
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^-…
We study the excited states of $ω$ and $ω_3$ by comparison with the $ρ$ and $ρ_3$ families, and discuss the possibility of $X(2220)$ as $ω$ excitation by analyzing the mass spectra and strong decay behaviors. In addition, we predict the masses and widths of $ω(2D)$ and $ω_3$and $ρ_3(4D)$, $ρ_3(1G)$, $ω_3$ and $ρ_3(2G)$ and $ω_3(3G)$ and $ρ_3(3G)$. The abundant information of their two-body strong decays predicted in this work will be helpful to further study of these $ω$ and $ω_3$ and $ρ$ and $ρ_3$ states in experiment and theory.
Two bottom $Σ_b(6097)^\pm$ baryons were observed in the final states $Λ_b^0π^-$ and $Λ_b^0π^+$ in $pp$ collision by LHCb collaboration, whose masses and widths were measured. In a $^{3}P_{0}$ model, the strong decay widths of two ground $S$-wave and seven excited $P$-wave $Σ_b$ baryons have been systematically computed. Numerical results indicate that the newly observed $Σ_b(6097)^\pm$ are very possibly $Σ_{b2}^1({3\over 2}^-)$ with $J^P={3\over 2}^-$ or $Σ_{b2}^1({5\over 2}^-)$ with $J^P={5\over 2}^-$. The predicted decay widths of $Σ_b(6097)^\pm$ are consistent with experimental measurement …
Stimulated by the recent observation of the $D_2^\ast(3000)$, we study the decay behaviors of the $3P$ and $2F$ charmed mesons in the present work. By comparing the masses and decay properties of the $3^3P_2$ and $2^3F_2$ charmed mesons with the observation of the $D_2^\ast(3000)$, we conclude that the most possible assignment of the $D_2^\ast(3000)$ is the $3^3P_2$ charmed meson, while the assignment of the $2^3F_2$ charmed meson could not be fully exclude. The results of the unobserved $3P$ and $2F$ charmed mesons in this work could provide some fundamental information of searching for these…
Using the effective Lagrangian approach, we study the decay behavior of the newly observed $B(5970)$ meson, which is assigned as the $2^3S_1$ state in the $B$ meson family. What is more important is that we predict the information of the partial and total decay decay widths of $B(2^1S_0)$, $B_s(2^1S_0)$ and $B_s(2^3S_1)$ as the spin and strange partners of $B(5970)$, which is valuable to future experimental search for these missing states.
Inspired by the newly observed $Λ_b(6072)$ structure, we investigate its strong decay behaviors under various assignments within the $^3P_0$ model. Compared with the mass and total decay width, our results suggest that the $Λ_b(6072)$ can be regarded as the lowest $ρ-$mode excitation in $Λ_b$ family. Then, the strong decays of $ρ-$mode nonstrange partners for the $Λ_b(6072)$ are calculated. It is found that the $J^P=5/2^-$ $Λ_b$ and $Λ_c$ states are relatively narrow, and mainly decay into the $Σ_b^{(*)} π$ and $Σ_c^{(*)} π$ final states, respectively. These two states have good potentials to …
Motivated by the newly observed narrow structures $Ω_b(6316)^-$, $Ω_b(6330)^-$, $Ω_b(6340)^-$, and $Ω_b(6350)^-$ in the $Ξ_b^0 K^-$ mass spectrum, we investigate the strong decays of the low-lying $Ω_b$ states within the $^3P_0$ model systematically. According to their masses and decay widths, the observed $Ω_b(6316)^-$, $Ω_b(6330)^-$, $Ω_b(6340)^-$, and $Ω_b(6350)^-$ resonances can be reasonably assigned as the $λ-$mode $Ω_b(1P)$ states with $J^P=1/2^-, 3/2^-, 3/2^-$, and $5/2^-$. Meanwhile, the remaining $P-$wave state with $J^P=1/2^-$ should have a rather broad width, which can hardly be ob…
Very recently, three new structures $Ξ_c(2923)^0$, $Ξ(2938)^0$, and $Ξ(2964)^0$ at the invariant mass spectrum of $Λ_c^{+}K^{-}$ observed by the LHCb Collaboration triggers a hot discussion about their inner structure. In this work, we study the strong decay mode of the newly observed $Ξ_c$ assuming that the $Ξ_c$ is a $\bar{D}Λ-\bar{D}Σ$ molecular state. With the possible quantum numbers $J^p=1/2^{\pm}$ and $3/2^{\pm}$, the partial decay widths of the $\bar{D}Λ-\bar{D}Σ$ molecular state into the $Λ_c^{+}K^{-}$, $Σ_c^{+}K^{-}$,and $Ξ_c^{+}π^{-}$ final states through hadronic loop are calculate…
After the discovery of the new $Ω^{*}$ state, the ratio of the branching fractions of $Ω(2012)\to \bar{K}πΞ$ relative to $\bar{K}Ξ$ decay channel was investigated by the Belle Collaboration recently. The measured $11.9\%$ up limit on this ratio is in sharp tension with the $S$-wave $\bar{K}Ξ(1530)$ molecule interpretation for $Ω(2012)$ which indicates the dominant $\bar{K}πΞ$ three-body decay. In the present work, we try to explore the possibility of the $P$-wave molecule assignments for $Ω(2012)$ (where $Ω(2012)$ has positive parity). It is found that the latest experimental measurements are …
Comparing the measured properties of the newly observed open-charm states D(2550), D(2600), D(2750), D(2760), D_{s1}(2710), D_{sJ}(2860), and D_{sJ}(3040) with our predicted spectroscopy and strong decays in a constituent quark model, we find that: (1) the $D(2\,^1S_0)$ assignment to D(2550) remains open for its too broad width determined by experiment; (2) the D(2600) and $D_{s1}(2710)$ can be identified as the $2\,^3S_1$-$1\,^3D_1$ mixtures; (3) if the D(2760) and D(2750) are indeed the same resonance, they would be the $D(1\,^3D_3)$; otherwise, they could be assigned as the $D(1\,^3D_3)$ an…
We study three newly observed D(2550), D(2610), and D(2760) by the BaBar Collaboration utilizing the mass spectra and investigating the strong decays. Our calculation indicates that D(2610) is an admixture of $2^3S_1$ and $1^3D_1$ with $J^P=1^-$. $D(2760)$ can be explained as either the orthogonal partner of D(2610) or $1^3D_3$. Our estimate of the decay width for $D(2550)$, assuming it as $2^1S_0$, is far below the experimental value. the threshold effect because the strong decay of $D(2550)\to D_0^*π$ is forbidden.} The decay behavior of the remaining two 1D charmed mesons, i.e., $^3D_2$ and…
In this work, we study the newly observed $D_J(3000)$ and $D_J^*(3000)$ through the analysis of mass spectrum and calculation of the corresponding two-body strong decay behaviors. Our results show that $D_J(3000)$ and $D_J^*(3000)$ are explained as the $2P(1^+)$ and $2^3P_0$ states in the $D$ meson family, respectively, which is supported by the calculated masses of these two states and their decay behaviors. As a byproduct, the decay behaviors of $3^1S_0$, $3^3S_1$, $2D(2^-)$, $2^3D_1$, $2D^\prime(2^-)$, $2^3D_3$, $2P^\prime(1^+)$, $2^3P_2$, $1F(3^+)$, $1^3F_2$, $1F^\prime(3^+)$, and $1^3F_4$…
The newly observed hidden-charm meson Zc(3900) with quantum numbers J(P) = 1(+) is considered as a hadronic molecule composed of DD*. We give detailed predictions for the decay modes Zc(+) -> J/psi + pi(+) + gamma and Zc(+) -> J/psi + pi(+) + l(+) + l(-) (l = e, mu) in a phenomenological Lagrangian approach.
We find that several thresholds can contribute to the enhancements of the newly observed heavy pentaquark candidates $P_c^+(4380)$ and $P_c^+(4450)$ via the anomalous triangle singularity (ATS) transitions in the specific kinematics of $Λ_b\to J/ψK^- p$. Apart from the observed two peaks we find that another peaks around 4.5 GeV can also be produced by the ATS. We also show that the $Σ_c^{(*)}$ can be produced at leading order in $Λ_b$ decay. This process is different from the triangle diagram and its threshold enhancement only appears as CUSP effects if there is no pole structure or the ATS i…
The two newly observed hidden-bottom mesons Zb(10610) and Zb'(10650) with quantum numbers J(P) = 1(+) are considered as hadronic molecules composed of BB(*) and B(*)B(*), respectively. We give predictions for the widths of the strong two-body decays Zb(+) to Upsilon(nS) + pi(+) and Zb'(+) to Upsilon(nS) + pi(+) in a phenomenological Lagrangian approach.
The newly reported exotic signal $Z_c(4100)$ by the LHCb Collaboration in the invariant mass spectrum of $η_cπ^-$ in $B^0\to η_c K^+ π^-$ has been a new experimental evidence for an exotic meson containing four constituent quarks. Although the present experimental information is very limited, we show that its correlations with some existing exotic candidates can be recognized. This signal can be either caused by final state interaction effects or a $P$-wave resonance state arising from the $D^*\bar{D}^*$ interaction. For the latter option its neutral partner will have exotic quantum numbers of…
In this article, we study the two body strong decays with the emission of light pseudo-scalar mesons $(π, η, K)$ for higher excited bottom states with in the framework of HQET. Inspired from the recent observation of bottom meson $B_{J}(5840)$ by LHCb collaboration \cite{9}, we classify the six possible $J^{P}$'s for this state on the basis of the theoretically available masses. By analyzing the strong decay widths and the branching ratios for all these six cases of $B_{J}(5840)$, we justify one of them to be the most favorable assignment for it. We also examined the recently observed bottom s…
Motivated by the newly observed resonance $X(2600)$ by BESIII Collaboration, we examine the trigluon glueball interpretation for it in the framework of QCD sum rules. We evaluate the mass spectra of the trigluon glueballs with quantum numbers $0^{-+}$ and $2^{-+}$ up to dimension 8 condensate in the operator product expansion. Our numerical results indicate that the mass of the $2^{-+}$ trigluon glueball is about $2.66\pm 0.06$ GeV, which is consistent with the mass of the X(2600) within the uncertainties, while $0^{-+}$ has a mass of $2.01\pm0.14$ GeV. The possible decay channels of the $2^{-…
The phenomenology of a newly developed model of hybrid meson decay is developed. The decay mechanism is based on the heavy quark expansion of QCD and the strong coupling flux tube picture of nonperturbative glue. A comprehensive list of partial decay widths of a wide variety of light, $s\bar s$, $c\bar c$, and $b \bar b$ hybrid mesons is presented. Results which appear approximately universal are highlighted along with those which distinguish different hybrid decay models. Finally, we examine several interesting hybrid candidates in detail.
We consider the nonleptonic B decays $ B \to D^{(*)} D_s(2317)$ and $ B \to D^{(*)} D_s(2460)$, involving the newly discovered $D_s(2317)$ and the $D_s(2460)$ states. We find that experiments indicate disagreement with model calculations of their properties and/or breakdown of the factorization assumption for these decays . We point out that decays involving $B_s$ mesons where the $D_s$ resonances can be produced via the weak decay of the $b$ quark can provide further information about the nature of these newly discovered states. We also propose a model to calculate the two body nonleptonic de…
Very recently a new enhancement around 4.05 GeV was observed by Belle experiment. In this short note, we discuss some possible assignments for this enhancement, i.e. $ψ(3S)$ and $D^*\bar{D}^*$ molecular state. In these two assignments, Y(4008) can decay into $J/ψπ^0π^0$ with comparable branching ratio with that of $Y(4008)\to J/ψπ^+π^-$. Thus one suggests high energy experimentalists to look for Y(4008) in $J/ψπ^0π^0$ channel. Furthermore one proposes further experiments to search missing channel $D\bar{D}$, $D\bar{D}^*+h.c.$ and especially $χ_{cJ}π^+π^-π^0$ and $η_cπ^+π^-π^0$, which will be h…
The two newly observed hidden-charm mesons Zc(+)[3900] and a possible partner state Zc'(+)[3950] with quantum numbers J(P) = 1(+) are considered as hadronic molecules composed of bar(D)D* and bar(D)* D*, respectively. We give predictions for the decay widths of the strong two-body transitions Zc(+) -> H + pi(+) and Zc' -> H + pi(+) with H = Psi(nS), hc(mP) in a phenomenological Lagrangian approach.
In this article, we study the strong decays of the newly observed charmed mesons $D(2550)$, $D(2600)$, $D(2750)$ and $D(2760)$ with the heavy quark effective theory in the leading order approximation, and tentatively identify the $(D(2550),D(2600))$ as the $2S$ doublet $(0^-,1^-)$ and the $(D(2750),D(2760))$ as the $1D$ doublet $(2^-,3^-)$, respectively. The identification of the $D(2750)$ and $D(2760)$ as the same particle with $J^P=3^-$ is disfavored.
Selecting the newly observed $Ξ_b(6227)^-$ by LHCb as a study example, we decode its inner structure by giving the mass spectrum analysis and the investigation of its two-body strong decay behaviors. Our result indicates that the $Ξ_b(6227)^-$ is a good candidate of the $P$-wave $Ξ_b^{\prime}$ state with $J^P=3/2^-$ or $5/2^-$. In addition, we further provide the information of the properties of the partners of the $Ξ_b(6227)^-$. These predicted states include three $2S$ states and the remaining $1P$ states in the bottom-strange baryon family. The calculated sizable Okubo-Zweig-Iizuka$-$allowe…
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…
We calculate branching ratios for pure penguin decay modes, $B\to ϕK$ decays using perturbative QCD approach. Our results of branching ratios are consistent with the experimental data and larger than those obtained from the naive factorization assumption and the QCD-improved factorization approach. This is due to a dynamical penguin enhancement in perturbative QCD approach.
The newly observed $Σ_b(6097)$ provides us a good chance to further construct the high excited states of the bottom baryon family. In this work, we explain the $Σ_b(6097)$ to be a $1P$ state with $J^P=5/2^-$ or $3/2^-$ by giving the mass spectrum analysis and the strong decay calculation, and predict the existence of $1P$ and $2S$ partners of the $Σ_b(6097)$, where their masses and the corresponding decay behaviors are presented. Because of the success of describing the $Σ_b(6097)$ and the former observed $Ξ_b(6227)$ under the quasi-two-body treatment to the bottom baryons, we continue to pred…
We study the charmed and bottomed doubly strange baryons within the heavy-quark-light-diquark framework. The two strange quarks are assumed to lie in $S$ wave and thus their total spin is 1. We calculate the mass spectra of the $S$ and $P$ wave orbitally excited states and find the $Ω_c^0 (2695)$ and $Ω_c^0 (2770)$ fit well as the $S$ wave states of charmed doubly strange baryons. The five newly $Ω_c^0(X)$ resonances observed by the LHCb Collaboration, i.e. $Ω_c^0(3000)$, $Ω_c^0(3050)$, $Ω_c^0(3066)$, $Ω_c^0(3090)$, and $Ω_c^0(3119)$, can be interpreted as the $P$ wave orbitally excited states…
To identify the nature of the newly observed charged resonance Zc(4200), we study its hadronic decays Zc(4200) -> J/psi pi, Zc(4200) -> eta_c rho and Zc(4200) -> D bar D* as a charmonium-like tetraquark state. In the framework of the QCD sum rules, we calculate the three-point functions and extract the coupling constants and decay widths for these interaction vertices. Including all these channels, the full decay width of the Zc(4200) state is consistent with the experimental value reported by the Belle Collaboration, supporting the tetraquark interpretation of this state.
We study the $\bar{K} Ξ$ decay mode of the newly observed $Ω(2012)$ assuming that the $Ω(2012)$ is a dynamically generated state with spin-parity $J^P = 3/2^-$ from the coupled channel $S$-wave interactions of $\bar{K}Ξ(1530)$ and $ηΩ$. In addition we also calculate its $KπΞ$ three-body decay mode. It is shown that the so-obtained total decay width is in fair agreement with the experimental data. We compare our results with those of other recent studies and highlight differences among them.
The newly-discovered $Ξ_{cc}^{++}$ decays into the $ Λ_{c}^+ K^-π^+π^+$, but the experimental data has indicated that this decay is not saturated by any two-body intermediate state. In this work, we analyze the multi-body weak decays of doubly heavy baryons $Ξ_{cc}$, $Ω_{cc}$, $Ξ_{bc}$, $Ω_{bc}$, $Ξ_{bb}$ and $Ω_{bb}$, in particular the three-body nonleptonic decays and four-body semileptonic decays. We classify various decay modes according to the quark-level transitions and present an estimate of the typical branching fractions for a few golden decay channels. Decay amplitudes are then param…
Recently the BES collaboration has announced observation of a resonant state in the $π^+π^- η'$ spectrum in $J/ψ\to γπ^+π^-η'$ decay. Fitting the data with a $0^{-+}$ state, the mass is determined to be 1833.7 MeV with $7.7σ$ statistic significance. This state is consistent with the one extracted from previously reported $p \bar p$ threshold enhancement data in $J/ψ\to γp \bar p$. We study the properties of this state using QCD anomaly and QCD sum rules assuming X(1835) to be a pseudoscalar and show that it is consistent with data. We find that this state has a sizeable matrix element $<0|G\ti…
The newly confirmed pentaquark state $P_c(4312)$ has been treated as a weakly bound $(Σ_c\bar{D})$ state by a well-established chiral constituent quark model and by a dynamical calculation on quark degrees of freedom where the quark exchange effect is accounted for. The obtained mass $4308$ MeV agrees with data. In this work, the selected strong decays of the $P_c(4312)$ state are studied with the obtained wave function. It is shown that the width of the $Λ_c\bar{D}^*$ decay is overwhelmed and the branching ratios of the $p\,η_c$ and $p\,J/ψ$ decays are both less than 1 percentage.
I discuss a QCD sum rule determination of the four-quark operator matrix elements contributing to the $Λ_b$ inclusive decay rates at the order $m_b^{-3}$. The results suggest that $1/m_b^3$ corrections are not responsible of the observed difference between the lifetimes of $Λ_b$ and $B_d$.
The conventional color-singlet model was challenged by the recent data on quarkonium production. Discrepancies in production rates were observed at the Tevatron, at LEP, and in fixed-target experiments. The newly advocated color-octet mechanism provides a plausible solution to the anomalous quarkonium production observed at the Tevatron. The color-octet mechanism should also affect other quarkonium production channels. In this paper we will summarize the studies of quarkonium production in $Z^0$ and $Υ$ decays.
We discuss possible options for interpreting the newly observed state Y(4140) by the CDF collaboration in $B^+\to J/ψϕK^+$ decay above the $J/ψϕ$ threshold, and argue that it is more likely to be a $D_s^*$-$D_s^*$ molecular state or an exotic ($J^{PC}=1^{-+}$) hybrid charmonium. We have discussed decay modes which would allow unambiguous identification of the hybrid charmonium option.
We review some results obtained by us and others concerning the structure of higher order perturbation series in perturbative QCD and their resummation using the renormalization group equation. We illustrate our results by a number of examples involving hadronic τdecays and e^+ e^- annihilation.
Recently, the BESIII Collaboration reported a new measurement of the $η_c ρ$ decay mode of $Z_c^{(\prime)}$, which motivated us to study the inner structure of $Z_c^{(\prime)}$ via investigating the hidden charm decays of these two $Z_c$ states. We consider the {triangle loop mechanism} contribution in the hidden charm decays of $Z_c^{(\prime)}$. Our estimations indicate that the triangle loop mechanism plays an important role in the decays of the $Z_c^{(\prime)}$, where our results are in agreement with the experimental observations in a reasonable parameter range. Furthermore, we point out t…
We choose the Reduction Formula, PCAC and Low Energy Theory to reduce the $S$ matrix of a OZI allowed two-body strong decay involving a light pseudoscalar, the covariant transition amplitude formula with relativistic wave functions as input is derived. After confirm this method by the decay $D^*(2010)\to Dπ$, we study the newly observed $D_{s0}(2590)^{+}$ with supposing it to be the state $D_s(2^1S_0)^+$, we find its decay width $Γ$ is highly sensitive to the $D_{s0}(2590)^{+}$ mass, which result in the meaningless comparison of widths by different models with various input masses. Instead of …
We study the newly reported hidden-charm pentaquark candidates $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ from the LHCb Collaboration, in the framework of the effective-range expansion and resonance compositeness relations. The scattering lengths and effective ranges from the $S$-wave $Σ_c\bar{D}$ and $Σ_c\bar{D}^*$ scattering are calculated by using the experimental results of the masses and widths of the $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$. Then we calculate the couplings between the $J/ψp,\,Σ_c\bar{D}$ channels and the pentaquark candidate $P_c(4312)$, with which we further estimate the …
