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.
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.
Three neutral resonances $Ξ_c(2923)^0$, $Ξ_c(2939)^0$ and $Ξ_c(2965)^0$ have been observed in the $Λ_c^+ K^-$ mass spectrum by the LHCb Collaboration. Given the $Ξ_c$ and $Ξ_c^\prime$ mass spectra predicted by the constituent quark models, these three resonances are tentatively treated as the $λ-$mode $Ξ_c(2S)$, $Ξ_c^\prime(2S)$, $Ξ_c^{\prime *}(2S)$, and $Ξ_c^\prime(1P)$ states, and their strong decay behaviors are calculated within the $^3P_0$ model. Our results indicate that the $Ξ_c(2923)^0$ and $Ξ_c(2939)^0$ can be clarified into the $J^P=3/2^-$ and $5/2^-$ $Ξ_c^\prime(1P)$ states respect…
Very recently Belle Collaboration reported observation of a narrow state called $Ω(2012)$ with mass $2012.4 \pm 0.7$~(stat)~$\pm 0.6$(syst)~MeV and width $6.4^{+2.5}_{-2.0}$~(stat)~$\pm 1.6$~(syst)~MeV. We calculate the mass and residue of $Ω(2012)$ state by employing the QCD sum rule method. Comparison of the obtained results with the experimental data allows us to interpret this state as $1P$ orbital excitation of the ground state $Ω$ baryon, i.e. with quantum numbers $J^P=\frac{3}{2}^-$.
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…
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 b…
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…
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^-…
In this work, we consider the canonical charmonium assignments for Y(4360) and Y(4660). Y(4660) is good candidate of $\rm 5 ^3S_1$ $c\bar{c}$ state, the possibility of Y(4360) as a $\rm 3 ^3D_1$ $c\bar{c}$ state is studied, and the charmonium hybrid interpretation of Y(4360) can not be excluded completely. We evaluate the $e^{+}e^{-}$ leptonic widths, E1 transitions, M1 transitions and the open flavor strong decays of Y(4360) and Y(4660). Experimental tests for the charmonium assignments are suggested.
The $D_{s0}(2590)^{+}$ resonance observed by LHCb Collaboration is a strong candidate of the $D_{s}(2^1S_0)$ state according to its spin parity and strong decay mode. However, the measured mass seems relatively lower than the previous theoretical predictions, which interests the coupled channel interpretations in the literature. In this work, we adopt an alternate approach, taking into account the screening effects in the potential model, to describe the $D_{s0}(2590)^{+}$ resonance. The mass spectrum and strong decays of the excited charmed-strange mesons are investigated within the modified …
We argue that the mass, production, total decay width, and decay pattern of the $η_2(1870)$ do not appear to contradict with the picture of it being the conventional $2 ^1D_2$ $q\bar{q}$ state. The possibility of the $η_2(1870)$ being a mixture of the conventional $q\bar{q}$ and the hybrid is also discussed.
Recently, LHCb collaboration has confirmed the state $X(4140)$, with a much larger width $Γ= 83\pm 21^{+21}_{-14}$ MeV than the previous experimental measurements, which has confused the understanding of its nature. We have investigated the possibility of the $χ_{c1}(3P)$ interpretation for the $X(4140)$, considering the mass and the strong decay properties.
Recently, the BES collaboration observed a broad resonant structure X(1576) with a large width being around 800 MeV and assigned its $J^{PC}$ number to $1^{--}$. We show that the isospin of this resonant structure should be assigned to 1. This state might be a molecule state or a tetraquark state. We study the consequences of a possible $K^*(892)$-${\bar κ}$ molecular interpretation. In this scenario, the broad width can easily be understood. By using the data of $B(J/ψ\to Xπ^0)\cdot B(X\to K^+K^-)$, the branching ratios $B(J/ψ\to Xπ^0)\cdot B(X\to π^+π^-)$ and $B(J/ψ\to Xπ^0)\cdot B(X\to K^+K…
The developments in the experimental facilities and analyses techniques have recently lead to the observation of many hadronic states ranging from excitations of conventional hadrons to various exotic states. The baryons with single heavy quark are among these states providing an attractive field of research to get a better understanding of the nonperturbative nature of the strong interaction. Recently, the Belle Collaboration announced observation of the state $Λ_c(2910)^+$ with a mass $2913.8\pm5.6\pm3.8~\mathrm{MeV}/c^2$ and width $51.8\pm20.0\pm18.8~\mathrm{MeV}$. In the present study, by …
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…
Recently, the LHCb Collaboration has confirmed the state $X(4140)$, with a mass $M=4146.5\pm 4.5^{+4.6}_{-2.8}$~MeV, and a much larger width $Γ=83\pm21^{+21}_{-14}$~MeV than the previous experimental measurements, which has confused the understanding of its nature. We will investigate the possibility of the $χ_{c1}(3P)$ interpretation for the $X(4140)$, considering the mass spectra predicted in the quark model, and the strong decay properties within the $^3P_0$ model. We also predict the strong decay properties of the charmonium states $χ_{c0}(3P)$ and $χ_{c2}(3P)$. Our results show that the $…
The spectrum and decay properties of radially excited $D_s$ states are examined in a new model. Good agreement is obtained with the properties of two recently announced $D_s$ mesons identified as $D_{s0}(2860) = c\bar{s}(2P)$ and $D^*_{s}(2690) = c\bar{s}$ as a possible mixture of $(2S;{}^3S_1)$ and $(1D;{}^3D_1)$. Searching for these mesons in B decays is advocated due to large predicted branching ratios.
In relation to the newly observed bottom-strange X^{+,-}(5568) mesons, we revisit our tetra-quark interpretation of X(3872) and Z_c(3900). It is discussed that our assignment of X^{+,-}(5568) to charged components of iso-triplet bottom partners of D_{s0}^+(2317) is compatible with the revised version of our tetra-quark interpretation of X(3872) and Z_c(3900).
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 …
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^{-…
We have used QCD sum rules to study the newly observed charged state $Z_c(4025)$ as a hidden-charm $D^*\bar D^*$ molecular state with the quantum numbers $I^G(J^{P})=1^+(1^{+})$. Using a $D^*\bar D^*$ molecular interpolating current, we have calculated the two-point correlation function and the spectral density up to dimension eight at leading order in $α_s$. The extracted mass is $m_X=(4.04\pm0.24)$ GeV. This result is compatible with the observed mass of $Z_c(4025)$ within the errors, which implies a possible molecule interpretation of this new resonance. We also predict the mass of the corr…
Precise measurements of $b\to cτ\barν$ decays require large resource-intensive Monte Carlo (MC) samples, which incorporate detailed simulations of detector responses and physics backgrounds. Extracted parameters may be highly sensitive to the underlying theoretical models used in the MC generation. Because new physics (NP) can alter decay distributions and acceptances, the standard practice of fitting NP Wilson coefficients to SM-based measurements of the $R(D^{(*)})$ ratios can be biased. The newly developed HAMMER software tool enables efficient reweighting of MC samples to arbitrary NP scen…
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…
Motivated by the very recent discovery of the strange hidden-charm exotic state $Z_{cs}(3985)$ by the BESIII Collaboration, we study possible interpretation of this exotic state both at $ T= 0 $ and $ T\neq 0 $. We analytically compute the mass and meson-current coupling constant of this resonance with spin-parity $ J^{PC} = 1^{+-}$ at finite temperature approximation up to sixth order of the thermal operator dimension including non-perturbative contributions. Extracting thermal mass and meson-current coupling constant sum rules, the modifications on properties of $Z_{cs}(3985)$ state in hot m…
Recently, a hadronic state named $η_1(1855)$, about 1.86 GeV, was observed in the BESIII experiment. This finding has a peculiar interest due to its exotic quantum number $J^{PC}=1^{-+}$. In this paper, we examine the tetraquark interpretation for the structure of $η_1(1855)$ in the configurations of $[1_c]_{\bar{s}s}\otimes[1_c]_{\bar{q}q}$ and $[1_c]_{\bar{s}q}\otimes[1_c]_{\bar{s}q}$, and perform a mass spectrum calculation in the framework of QCD sum rules. The results show that the observed $η_1(1855)$ could be embedded into the $[1_c]_{\bar{s}s}\otimes[1_c]_{\bar{q}q}$ configuration. The…
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…
