Search

The nonleptonic weak decay processes Ωc→Ωπ+/Ω(1P)π+/Ω(1D)π+/Ω(2S)π+ are studied using the constituent quark model. The branching fraction of Ωc→Ωπ+ is predicted to be 1.05%. Considering the newly observed Ω(2012) resonance as a conventional 1P-wave Ω excited state with spin parity JP=3/2−, the newly measured ratio B[Ωc→Ω(2012)π+→(ΞK¯)−π+]/B[Ωc→Ωπ+] at Belle can be well understood. Besides, the production rates for the missing 1P-wave state Ω(12P1/2−), two spin quartet 1D-wave states Ω(14D1/2+) and Ω(14D3/2+), and two 2S-wave states Ω(22S1/2+) and Ω(24S3/2+) are also investigated. It is expected that these missing excited Ω baryons should have large potentials to be discovered through the nonleptonic weak decays of Ωc in forthcoming experiments by Belle II and/or LHCb.

We perform a systematic analysis of the mass and strong decays of the Ω(2012) resonance in a coupled-channel approach of a bare three-quark state and a composite meson-baryon state. Besides the coupling of the bare state and Ξ*K¯ channel, the effective meson-baryon interactions are also included. We find a pole with a mass of 2008 MeV by solving the Bethe-Salpeter equation. The calculated decay widths and its ratios of branching fractions RΞK¯ΞπK¯ agree well with the new experimental measurement by the Belle Collaboration. Our results suggest that both three-quark core and Ξ*K¯ channel are essential for the description of the Ω(2012) resonance. We expect that present calculations can help us to better understand the nature of Ω(2012) resonance.

The Ds0(2590)+ resonance observed by LHCb Collaboration is a strong candidate of the Ds(21S0) 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 Ds0(2590)+ resonance. The mass spectrum and strong decays of the excited charmed-strange mesons are investigated within the modified relativized quark model and P03 model. The calculated mass and width of the Ds0(2590)+ are consistent with the experimental observations, which indicate that it can be reasonably interpreted as the Ds(21S0) state.

We reanalyze the problems in the assignment of 3S13 and 4S13 light mesons, which have not yet been well established with the qq¯ quark model. Regge trajectories and the P03 decay model are used, respectively, to study the mass and width of the observed states and predict the missing ones. By comparing our calculations with the latest experiments, we suggest that the inconsistent data of ρ(2150) may include two similar structures, ρ(4S31) and ω(4S31). In addition, the problem of the K*(2S31) assignment, with two observed states K*(1410) and K*(1680), is investigated, with several possible explanations.

In the present work, the mass spectra of doubly heavy tetraquarks TQQ′ are systematically investigated in a relativized quark model. The four-body systems including the Coulomb potential, confining potential, spin-spin interactions, and relativistic corrections are solved within the variational method. Our results suggest that the IJP=01+ bbu¯d¯ state is 54 MeV below the relevant B¯B¯* thresholds, which indicates that both strong and electromagnetic decays are forbidden, and thus this state can be a stable one. Its large hidden color component and small root mean square radius demonstrate that it is a compact tetraquark rather than a loosely bound molecule or pointlike diquark-antidiquark structure. Our predictions of the doubly heavy tetraquarks may provide valuable information for future experimental searches.

In this work, we perform a systematic study of the strong decays for the higher singly heavy baryon resonances ΛQ(3S), ΛQ(2P), ΛQ(2D), ΛQ(1F), ΣQ(3S), ΣQ(2P), ΣQ(2D), and ΣQ(1F) within the P03 model. Our results show that most of the λ-mode higher excited ΛQ and ΣQ 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.

The strong decays of the low-lying λ-mode Λb(1D,2S) and Σb(2S) states are studied in a chiral quark model. We find that (i) the newly observed Λb(6146/6152) resonances in the Λbπ+π− spectrum by the LHCb Collaboration might be explained with the λ-mode Λb(1D) states in the quark model. It should be emphasized that whether the structure in the Λbπ+π− spectrum corresponds to two states or one state should be further clarified with more observations in future experiments. (ii) The Λb(2S) |JP=12+,0⟩ state mainly decays into Σb*π channel, which may be an ideal channel for searching for this Λb(2S) state in future experiments. (iii) The Σb(2S) |JP=12+,1⟩ and |JP=32+,1⟩ dominantly decay into Λbπ with Γ≃3.82 MeV and Γ≃4.72 MeV, respectively.

Stimulated by the newly observed Λb(6146)0 and Λb(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 Λb(2S), Λb(1D), Σb(2S), and Σb(1P) states and then estimate their strong decay widths. Compared with the experimental total widths and decay modes measured by the LHCb Collaboration, the Λb(6146)0 and Λb(6152)0 can be reasonably clarified into the JP=5/2+ and JP=3/2+ Λb(1D) states, 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.

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 P03 model. It is found that Ω(2012) is most likely to be a 1P-wave Ω state with JP=3/2−. We also find that the Ω(2250) state could be assigned as a 1D-wave state with JP=5/2+. The other missing 1P- and 1D-wave Ω baryons may have large potentials to be observed in their main decay channels.

In this work, we study strong and radiative decays of S-wave DΞ molecular state, which is related to the Ωc* states newly observed at LHCb. The coupling between the DΞ molecular state and its constituents D and Ξ is calculated by using the compositeness condition. With the obtained coupling, the partial decay widths of the DΞ molecular state into the Ξc+K−, Ξc′+K−, and Ωc*(2695)γ final 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 Ωc*(3119) or Ωc*(3050) as DΞ molecule while the decay width of the Ωc*(3000), Ωc*(3066), and Ωc*(3090) can not be well reproduced in the molecular state picture. The partial decay widths are also presented and helpful to further understand the internal structures of Ωc*(3119) and Ωc*(3050).