[en] The strong decays of P"+_c(4380)→J/ψp and P"+_c(4450)→J/ψp are studied based on a Σ_cD¯"∗ molecule scenario. Different assignments for the spin-parity of the two P_c states are considered. Our results exclude all the P- wave Σ_cD¯"∗ assignments, while the estimated widths of the S wave are both allowed by the present experimental data of the two P_c states. Moreover, we discuss the other two scenarios of Σ"∗_cD¯ and Σ"∗_cD¯"∗ in heavy quark limit with J"P =3/2"−, and find the Σ"∗_cD ¯ system for P_c(4380) might be possible. (author)

[en] 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${}_c^{\mathrm{\prime <!--\; ???\; -->}}$ mass spectra predicted by the constituent quark models, these three resonances are tentatively treated as the λ-mode Ξ${}_c$(2S), Ξ${}_c^{\mathrm{\prime <!--\; ???\; -->}}$(2S), Ξ${}_c^{\mathrm{\prime <!--\; ???\; -->}\text{â<!-- ?? -->}\text{ˆ<!-- ?? -->}\text{—<!-- ??? -->}}$(2S), and Ξ${}_c^{\mathrm{\prime <!--\; ???\; -->}}$(1P) states, and their strong decay behaviors are calculated within the ${}^3$P${}_0$ 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${}_c^{\mathrm{\prime <!--\; ???\; -->}}$(1P) states respectively, and the Ξ${}_c$(2965)${}^0$ can be regarded as the JP=1/2${}^{+}$ Ξ${}_c^{\mathrm{\prime <!--\; ???\; -->}}$(2S) state. Also, we suggest that the previous observed Ξ${}_c$(2930) may be the overlap of two structures Ξ${}_c$(2923) and Ξ${}_c$(2939), and the Ξ${}_c$(2970) should be the same state as Ξ${}_c$(2965). Other theoretical information on the missing Ξ${}_c$(2S), Ξ${}_c^{\mathrm{\prime <!--\; ???\; -->}\text{â<!-- ?? -->}\text{ˆ<!-- ?? -->}\text{—<!-- ??? -->}}$(2S), and Ξ${}_c^{\mathrm{\prime <!--\; ???\; -->}}$(1P) states may be helpful for future experimental searches.

[en] Inspired by the newly observed Λ${}_b$(6072) structure, we investigate its strong decay behaviors under various assignments within the ${}^3$P${}_0$ 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${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$ Λ${}_b$ and Λ${}_c$ states are relatively narrow, and mainly decay into the Σ${}_b^{(\text{â<!-- ?? -->}\text{ˆ<!-- ?? -->}\text{—<!-- ??? -->})}$π and Σ${}_c^{(\text{â<!-- ?? -->}\text{ˆ<!-- ?? -->}\text{—<!-- ??? -->})}$π final states, respectively. These two states have good potentials to be observed in future experiments, which may help us to distinguish the three-quark model and diquark model.

[en] Motivated by the newly observed narrow structures Ω${}_b$(6316)${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$, Ω${}_b$(6330)${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$, Ω${}_b$(6340)${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$, and Ω${}_b$(6350)${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$ in the Ξ${}_b^0$K${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$ mass spectrum, we investigate the strong decays of the low-lying Ω${}_b$ states within the ${}^3$P${}_0$ model systematically. According to their masses and decay widths, the observed Ω${}_b$(6316)${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$, Ω${}_b$(6330)${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$, Ω${}_b$(6340)${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$, and Ω${}_b$(6350)${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$ resonances can be reasonably assigned as the λ−mode Ω${}_b$(1P) states with J${}^P$=1/2${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$,3/2${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$,3/2${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$, and 5/2${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$. Meanwhile, the remaining P−wave state with J${}^P$=1/2${}^{\text{â<!-- ?? -->}}\text{ˆ<!-- ?? -->}\text{’<!-- ??? -->}$ should have a rather broad width, which can hardly be observed by experiments. For the Ω${}_b$(2S) and Ω${}_b$(1D) states, our predictions show that these states have relatively narrow total widths and mainly decay into the Ξ${}_b\stackrel{¯<!--\; ??\; -->}{K}$, Ξ${}_b^{\mathrm{\prime <!--\; ???\; -->}}$$\stackrel{¯<!--\; ??\; -->}{K}$ and Ξ${}_b^{\mathrm{\prime <!--\; ???\; -->}\text{â<!-- ?? -->}\text{ˆ<!-- ?? -->}\text{—<!-- ??? -->}}$$\stackrel{¯<!--\; ??\; -->}{K}$ final states. These abundant theoretical predictions may be valuable for searching more excited Ω${}_b$ states in future experiments.

[en] The exotic states X${}_{0,1}$(2900) with the quark flavor of $cs\stackrel{¯<!--\; ??\; -->}{u}\stackrel{¯<!--\; ??\; -->}{d}$ are recently observed in the mass spectrum of D${}^{+}$K${}^{-<!--\; ???\; -->}$ in B${}^{-<!--\; ???\; -->}$ → D${}^{-<!--\; ???\; -->}$D${}^{+}$K${}^{-<!--\; ???\; -->}$ by the LHCb collaboration. To explore the nature of X${}_{0,1}$(2900), except for analyzing their masses and decay widths as usually did in literatures, the study of their production mechanism in B-meson weak decays would provide another important information. The amplitude of B${}^{-<!--\; ???\; -->}$ → D${}^{-<!--\; ???\; -->}$X${}_{0,1}$ is non-factorizable. We consider the final-state-interaction effects and calculate them via the rescattering mechanism. The measured branching fractions of B${}^{-<!--\; ???\; -->}$ → D${}^{-<!--\; ???\; -->}$X${}_{0,1}$ are revealed. It is manifested by B${}^{-<!--\; ???\; -->}$ → Λ${}_c^{-<!--\; ???\; -->}$Ξ${}_c^{(\mathrm{\prime <!--\; ???\; -->})0}$ and Λ${}_b^0$ → P${}_c^{+}$K${}^{-<!--\; ???\; -->}$ that the rescattering mechanism can result in the relatively large branching fractions. The similar processes of B${}^{-<!--\; ???\; -->}$ → π${}^{-<!--\; ???\; -->}$X${}_{0,1}$ are also analyzed. The isospins of X${}_{0,1}$ can be investigated by B → DX${}_{0,1}^{\pm <!--\; ??\; -->,0}$ decays.

[en] 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$\stackrel{¯<!--\; ??\; -->}{b}$ 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.

[en] The role of the Λ(1670) resonance in the γp → K"+ ηΛ reaction near threshold is studied within an effective Lagrangian approach. We perform a calculation for the total and differential cross section of the γp → K"+ ηΛ reaction by including the contributions from the Λ(1670) intermediate state decaying into ηΛ dominated by K"- and K"*"- mesons exchanges, the nucleon pole and N*(1535) resonance decaying into K"+ Λ dominated by exchanges of ω and K"- mesons. Besides, the non-resonance process and contact terms to keep the total scattering amplitude gauge invariant are also considered. With our model parameters, the total cross section of this reaction is of the order of 1 nanobarn at photon beam energy E_γ ∝ 2.5 GeV. It is expected that our model predictions could be tested by future experiments. (orig.)

[en] Considering the mass, parity and D⁰p 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 ³P₀ model, we obtain that the total decay widths of the Λ_c1((1)/(2)^-, 2P) and Λ_c1((3)/(2)^-, 2P) states are 16.27 and 25.39 MeV, respectively. Compared with the experimental total width 27.7^+8.2_-6.0 ± 0.9^+5.2_-10.4 MeV measured by LHCb Collaboration, both assignments are allowed, and the J^P = (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. (orig.)

[en] Inspired by recent measurement of possible fully charmed tetraquarks in LHCb Collaboration, we investigate the mass spectra of fully heavy tetraquarks $QQ\stackrel{¯<!--\; ??\; -->}{Q}\stackrel{¯<!--\; ??\; -->}{Q}$ in an extended relativized quark model. Our estimations indicate that the broad structure around 6.4 GeV should contain one or more ground states for $cc\stackrel{¯<!--\; ??\; -->}{c}\stackrel{¯<!--\; ??\; -->}{c}$ tetraquarks, while the narrow structure near 6.9 GeV can be categorized as the first radial excitation of c$cc\stackrel{¯<!--\; ??\; -->}{c}\stackrel{¯<!--\; ??\; -->}{c}$ system. Moreover, with the wave functions of the tetraquarks and mesons, the strong decays of tetraquarks into heavy quarkonium pair are qualitatively discussed, which can be further checked by the LHCb and CMS Collaborations.

[en] Using the Regge-like formula (M - m_Q)² = πσL between hadron mass M and angular momentum L with a heavy quark mass m_Q and a string tension σ, we analyze all the heavy-light systems, i.e., D/D_s/B/B_s mesons and charmed and bottom baryons. Numerical plots are obtained for all the heavy-light mesons of experimental data whose slope becomes nearly equal to 1/2 of that for light hadrons. Assuming that charmed and bottom baryons consist of one heavy quark and one light cluster of two light quarks (diquark), we apply the formula to all the heavy-light baryons including the recently discovered Ω_c and find that these baryons experimentally measured satisfy the above formula. We predict the average mass values of B, B_s, Λ_b, Σ_c, Ξ_c, and Ω_c with L = 2 to be 6.01, 6.13, 6.15, 3.05, 3.07, and 3.34 GeV, respectively. Our results on baryons suggest that these baryons can be safely regarded as heavy quark-light cluster configuration. We also find a universal description for all the heavy-light mesons as well as baryons, i.e., one unique line is enough to describe both of charmed and bottom heavy-light systems. Our results suggest that instead of mass itself, gluon flux energy is essential to obtain a linear trajectory. Our method gives a straight line for B_c although the curved parent Regge trajectory was suggested before. (orig.)