arXiv subjects

Qi-Xin Yu

Publications and source records attributed to Qi-Xin Yu.

5 recordsLinked to original sources

arXiv2020

$Ξ_{bb}$ and $Ω_{bbb}$ molecular states

Using the vector-exchange interaction in the local hidden gauge approach, which in the light quark sector generates the chiral Lagrangian, and has produced realistic results for $Ω_c, Ξ_c, Ξ_b$ and the hidden charm pentaquark states, we study the meson-baryon interactions in the coupled channels that lead to the $Ξ_{bb}$ and $Ω_{bbb}$ excited states of the molecular type. We obtain seven states of the $Ξ_{bb}$ type with energies between $10408$ and $10869$ MeV and one $Ω_{bbb}$ state at $15212$ MeV.

hep-ph↗

arXiv2019

Molecular $Ξ_{bc}$ states from meson-baryon interaction

We have studied the meson-baryon interaction in coupled channels with the same quantum numbers of $Ξ_{bc}$. The interaction is attractive in some channels and of sufficient intensity to lead to bound states or resonances. We use a model describing the meson-baryon interaction based on an extrapolation of the local hidden gauge approach to the heavy sector, which has been successfully used in predicting $Ω_c$ and hidden charm states. We obtain many states, some of them narrow or with zero width, as a consequence of the interaction, which qualify as molecular states in those channels. The success in related sectors of the picture used should encourage the experimental search for such states.

hep-ph↗

arXiv2019

$B_{s1}(5778)$ as a $B^*\bar{K}$ molecule in the Bethe-Salpeter equation approach

We interpret the $B_{s1}(5778)$ as an $S$-wave $B^\ast\bar{K}$ molecular state in the Bethe-Salpeter equation approach. In the ladder and instantaneous approximations, and with the kernel containing one-particle-exchange diagrams and introducing three different form factors (monopole, dipole, and exponential form factors) in the vertex, we find the bound state exists. We also study the decay widths of the decay $B_{s1}(5778)\rightarrow B_s^\astπ$ and the radiative decays $B_{s1}(5778)\rightarrow B_sγ$ and $B_{s1}(5778)\rightarrow B_s^{\ast}γ$, which will be instructive for the forthcoming experiments.

hep-ph↗

arXiv2018

Masses of doubly heavy baryons in the Bethe-Salpeter equation approach

A doubly heavy baryon can be regarded as composed of a heavy diquark and a light quark. In this picture, we study the masses of the doubly heavy diquarkes in the Bethe-Salpeter (BS) formalism first, which are then used as one of the inputs in studying the masses of the doubly heavy baryons in the quark-diquark model. We establish the BS equations for both the heavy diquarks and the heavy baryons with and without taking the heavy quark limit, respectively. These equations are solved numerically with the kernel containing the scalar confinement and one-gluon-exchange terms. The mass of the doubly charmed baryon $Ξ_{cc}^{(\ast)}$ is obtained in both approaches, $3.60\sim3.65\,\rm GeV$ ($Ξ_{cc}^{(\ast)}$) under the heavy quark limit, $3.53\sim3.56\,\rm GeV$ for $Ξ_{cc}$ and $3.61\sim3.63\,\rm GeV$ for $Ξ_{cc}^\ast$ without taking the heavy quark limit. The masses of $Ξ_{bc}^\prime$, $Ξ_{bc}^{(\ast)}$, $Ξ_{bb}^{(\ast)}$, $Ω_{cc}^{(\ast)}$, $Ω_{bc}^\prime$, $Ω_{bc}^{(\ast)}$ and $Ω_{bb}^{(\ast)}$ are also predicted in the same way. We find that the corrections to the results in the heavy quark limit are about $-0.02\,\rm GeV\sim-0.11\,\rm GeV$ for the masses of the doubly heavy baryons.

hep-ph↗

arXiv2018

Residues of $Λ_Q$-type and $Σ_Q$-type Baryons in the Bethe-Salpeter Equation Approach

We study the residues of $Λ_Q$-type baryons ($Λ_Q$ and $Ξ_Q^A$) $(Q=b,c)$ and $Σ_Q$-type baryons ($Σ_Q^{(\ast)}$, $Ξ_Q^{S(\ast)}$ and $Ω_Q^{(\ast)}$) in the quark-diquark model within the Bethe-Salpeter (BS) formalism. These residues can be used, for example, in the calculations of the amplitudes in the scattering processes. After constructing the baryonic currents in the BS formalism, we derive the relations between the BS wave functions and the residues for these baryons. The BS equations are solved numerically with the kernel including the scalar confinement and the one gluon exchange terms and with the covariant instantaneous approximation being employed in the calculations. Finally, we obtain the numerical values of the residues $0.103\,\rm GeV\sim0.224\,\rm GeV$ for $Λ_Q$, $0.143\,\rm GeV\sim0.215\,\rm GeV$ for $Ξ_Q^A$, $0.262\,\rm GeV\sim0.361\,\rm GeV$ for $Σ_Q^{(\ast)}$, $0.313\,\rm GeV\sim0.460\,\rm GeV$ for $Ξ_Q^{S(\ast)}$ and $0.473\,\rm GeV\sim0.571\,\rm GeV$ for $Ω_Q^{(\ast)}$ in the ranges of the parameters in our model.

hep-ph↗