Single Heavy Baryons Research Articles

Strong decay properties of single heavy baryons ΛQ, ΣQ and ΩQ

Motivated by recent progresses in experiments in searching for the [Formula: see text] baryons, we systematically analyze the strong decay behaviors of single heavy baryons [Formula: see text], [Formula: see text] and [Formula: see text]. The two-body strong decay properties of [Formula: see text]-wave, [Formula: see text]-wave and some [Formula: see text]-wave states are studied with the [Formula: see text] model. The results support assigning the recently observed [Formula: see text] and [Formula: see text] as the 2S([Formula: see text]) and 1D([Formula: see text]) states, respectively. In addition, the quantum numbers of many other experimentally observed baryons are also suggested according to their strong decays. Finally, some baryons which have good potentials to be observed in experiments are predicted and the possible decay channels for searching for these predicted states are also suggested.

Systematic analysis of strange single heavy baryons and * *Supported by the National Natural Science Foundation of China (11675265, 12175068), the Continuous Basic Scientific Research Project (WDJC-2019-13), the Leading Innovation Project (LC 192209000701) and the Central Government Guidance Funds for Local Scientific and Technological Development of China (Guike ZY22096024)

Motivated by the experimental progress in the study of heavy baryons, we investigate the mass spectra of strange single heavy baryons in the λ-mode, using the relativistic quark model and the infinitesimally shifted Gaussian basis function method. We show that experimental results are well captured using the predicted masses. The root mean square radii and radial probability density distributions of the wave functions are analyzed in detail. Meanwhile, the mass spectra allow us to successfully construct the Regge trajectories in the plane. We also preliminarily assign quantum numbers to the recently observed baryons, including , , , , , , , , , , , and . Finally, the spectral structure of strange single heavy baryons is discussed. Accordingly, we predict several new baryons that may be observed in forthcoming experiments.

Systematic analysis of single heavy baryons ΛQ, ΣQ and ΩQ

Motivated by great progresses in experiments in searching for the heavy baryons, we systematically analyze the mass spectra and root mean square radius of single heavy baryons ΛQ, ΣQ and ΩQ. The calculations of the mass spectra are carried out in the frame work of relativized quark model, where the baryon is regarded as a three-body system of quarks. Our results show that the mass of single heavy baryon with λ-mode is lower than those of the ρ-mode and λ-ρ mixing mode, which indicates that the lowest state is dominated by the λ-mode. Basing on this research, we systematically calculate the mass spectra and the root mean square radius of the baryons with λ excited mode. With these predicated mass spectra, the Regge trajectories in the (J, M2) plane are constructed, and the slopes, intercepts of the Regge trajectories are obtained by linear fitting. It is found that all available experimental data are well reproduced by model predictions and fit nicely to the constructed Regge trajectories.

Excitation spectra of heavy baryons in diquark models

Abstract The excitation energy spectra of heavy baryons consisting of a heavy quark and two light quarks are investigated using diquark models in order to examine the nature of the diquark as a constituent of single heavy baryons. We consider two diquark models; in Model A the diquark is treated as a point-like particle, while it has a spatial size in Model B. We determine the masses of scalar and axial vector diquarks by the mass difference of the ground-state charmed baryons and the Λc baryon, while the mass of the ud scalar diquark in the Λc baryon is assumed to be 500 MeV as a reference. The parameters of these models are fixed by the 1p excitation energy of Λc. We find that Model A reproduces well the excitation energy spectra of the charmed and bottomed baryons, although the string tension of the confinement potential in Model A should be half of that of the charmonium, while Model B suggests degeneracy of the 2s and 1d states, which is not seen in the Λc spectrum.

Universal behavior of mass gaps existing in the single heavy baryon family

The mass gaps existing in the discovered single heavy flavor baryons are analyzed, which show some universal behaviors. Under the framework of a constituent quark model, we quantitatively explain why such interesting phenomenon happens, when these established excited heavy baryons are regarded as the lambda -mode excitations. Based on the universal behaviors of the discussed mass gaps, we may have three implications including the prediction of the masses of excited Xi _b^0 baryons which are still missing in the experiment. For completeness, we also discuss the mass gaps of these rho -mode excited single heavy flavor baryons.

Study of bottom and charmed baryons in quark-diquark model

In this work, we study the properties of charm- and bottom-flavored baryons in the approximative quark-diquark modelin which the structure of baryons is considered as the bound states of quark-diquark pairs instead of the usual three equivalent quarks. To this aim, we use the Bethe-Salpeter equation including the Yukawa potential between the constituent quarks of baryons. Performing a fit procedure on the baryon masses in their ground state, we first determine the free parameters in the Yukawa potential and then compute the heavy baryons masses and energies in their excited states. We will also compute the magnetic moments of single heavy baryons as well as their semileptonic decay widths by evaluating the Isgur-Wise functions (IWF) for heavy baryons. Our results will be compared with available experimental data and other models so that the consistencies between them ensure the validity of IWF parameters extracted for the transitions of bottom baryons into charmed ones. Relying on the diquark model, we shall also predict the properties of some levels which have not yet observed.

S-wave single heavy baryons with spin-3/2 at finite temperature

The thermal behavior of the spectroscopic parameters of the S-wave single heavy baryons Sigma _{Q}^{*}, Xi _{Q}^{*} and Omega _{Q}^{*} with spin-3/2 are investigated in QCD at finite temperature. We analyze the variations of the mass and residue of these baryons taking into consideration the contributions of QCD thermal condensates up to dimension eight in Wilson expansion. At finite temperature, due to the breakdown of the Lorentz invariance by the choice of reference frame and presence of an extra O(3) symmetry, some new four-dimensional operators come out in the form of the fermionic and gluonic parts of the energy momentum tensor that are taken into account in the calculations. Our analyses show that at lower temperatures, the parameters of baryons under consideration are not affected by the medium. These parameters, however, show rapid variations with respect to temperature at higher temperatures near to a pseudo-critical temperature, after which the baryons are melted. The results of the masses and residues at Trightarrow 0 limit are compatible with the available experimental data and predictions of other theoretical studies.

Novel Ideas in Nonleptonic Decays of Double Heavy Baryons

The recent discovery of double charm baryon states by the LHCb Collaborarion and their high precision mass determination calls for a comprehensive analysis of the nonleptonic decays of double and single heavy baryons. Nonleptonic baryon decays play an important role in particle phenomenology since they allow for studying the interplay of long and short distance dynamics of the Standard Model (SM). Furthermore, they allow one to search for New Physics effects beyond the SM. We review recent progress in experimental and theoretical studies of the nonleptonic decays of heavy baryons with a focus on double charm baryon states and their decays. In particular, we discuss new ideas proposed by the present authors to calculate the W-exchange matrix elements of the nonleptonic decays of double heavy baryons. An important ingredient in our approach is the compositeness condition of Salam and Weinberg, and an effective implementation of infrared confinement both of which allow one to describe the nonperturbative structure of baryons composed of light and heavy quarks. Furthermore, we discuss an ab initio calculational method for the treatment of the so-called W-exchange diagrams generated by W ± boson exchange between quarks. We found that the W ± -exchange contributions are not suppressed in comparison with the tree-level (factorizing) diagrams and must be taken into account in the evaluation of matrix elements. Moreover, there are decay processes such as the doubly Cabibbo-suppressed decay Ξ c + → p ϕ recently observed by the LHCb Collaboration, which is contributed to only by one single W-exchange diagram.

Singly heavy baryons with chiral partner structure in a three-flavor chiral model

We construct an effective hadronic model including single heavy baryons (SHBs) belonging to the $(\mathbf{3},\mathbf{3})$ representation under $\mbox{SU}(3)_L \times \mbox{SU}(3)_R$ symmetry, respecting the chiral symmetry and heavy-qaurk spin-flavor symmetry. When the chiral symmetry is spontaneously broken, the SHBs are divided into the baryons with negative parity of $\bar{\mathbf 3}$ representation under $\mbox{SU}(3)$ flavor symmetry which is the chiral partners to the ones with positive parity of ${\mathbf 6}$ representation. We determine the model parameters from the available experimental data for the masses and strong decay widths of $\Sigma_c^{(\ast)}$, $\Lambda_c (2595)$, $\Xi_c (2790)$, and $\Xi_c (2815)$. Then, we predict the masses and strong decay widths of other baryons including $\Xi_b$ with negative parity. We also study radiative decays of SHBs including $\Omega_c^\ast$ and $\Omega_b^\ast$ with positive parity.

Study of Charmed and Bottom Baryons in a Variational Approach and Chiral Interactions

Models have been widely used to study charmed and bottom baryons. In this work using the confining, one gluon exchange and Goldstone boson exchange terms as inter-quark interactions, we study the heavy flavour baryon spectrum in the framework of the constituent quark model. We use a variational method to solve the non-relativistic three-body problem for baryons in the hypercentral approach. The masses of heavy baryons containing one, two, and three heavy flavour quarks are found to be in accordance with the existing experimental values or with other theoretical predictions. The magnetic moments of single heavy baryons with J^p=3/2^+ are also obtained.

Single heavy flavour baryons using Coulomb plus a power law interquark potential

Properties of single heavy flavor baryons in a non-relativistic potential model with colour Coulomb plus a power law confinement potential have been studied using a simple variational method. The ground-state masses of single heavy baryons and the mass difference between the J P = $ {\frac{{3}}{{2}}}$ + and J P = $ {\frac{{1}}{{2}}}$ + states are computed using a spin-dependent two-body potential. Using the spin-flavour structure of the constituting quarks and by defining an effective confined mass of the constituent quarks within the baryons, the magnetic moments are computed. The masses and magnetic moments of the single heavy baryons are found to be in accordance with the existing experimental values and with other theoretical predictions. It is found that an additional attractive interaction of the order of -200 MeV is required for the antisymmetric states of $ \Lambda_{{Q}}^{}$ (Q $ \in$ c, b) . It is also found that the spin-hyperfine interaction parameters play a decisive role in hadron spectroscopy.

Diquark representations for single heavy baryons with light staggered quarks

In the staggered fermion formulation of lattice QCD, we construct and classify the diquark operators to be embedded in the singly heavy baryons, $qqQ$. Along the same manner as in the staggered meson classifications given in [M. F. L. Golterman, Nucl. Phys. B273, 663 (1986).], we establish the group theoretical connections between continuum and lattice staggered diquark representations.