Baryon States Research Articles

Predicting a new resonance as charmed-strange baryonic analog of Ds0*(2317)

By an unquenched quark model, we predict a charmed-strange baryon state, namely, the $\Omega_{c0}^d(1P,1/2^-)$. Its mass is predicted to be 2945 MeV, which is below the $\Xi_c\bar{K}$ threshold due to the nontrivial coupled-channel effect. So the $\Omega_{c0}^d(1P,1/2^-)$ state could be regraded as the analog of the charmed-strange meson $D_{s0}^*(2317)$. It is a good opportunity for the running Belle II experiment to search for this state in the $\Omega_c^{(*)}\gamma$ mass spectrum experiment in the future.

Hadronic coupling constants of the lowest hidden-charm pentaquark state, using QCD sum rules with rigorous quark-hadron duality * *Supported by National Natural Science Foundation of China (11775079)

In this article, we illustrate how to calculate the hadronic coupling constants of the pentaquark states with QCD sum rules based on rigorous quark-hadron quality. We then study the hadronic coupling constants of the lowest diquark-diquark-antiquark type hidden-charm pentaquark state with spin-parity in detail, and calculate the partial decay widths. The total width is compatible with the experimental value from the LHCb collaboration, and favors assigning the to be the pentaquark state with . The hadronic coupling constants have the relation , and favor the hadronic dressing mechanism. The may have a diquark-diquark-antiquark type pentaquark core with the typical size of the -type baryon states. The strong couplings to the meson-baryon pairs lead to some pentaquark molecule components, and the may spend a rather large time as the molecular state.

Masses of positive- and negative-parity hadron ground-states, including those with heavy quarks

A symmetry-preserving treatment of a vector times vector contact interaction is used to compute spectra of ground-state J^P = 0^pm , 1^pm (f{bar{g}}) mesons, their partner diquark correlations, and J^P=1/2^pm , 3/2^pm (fgh) baryons, where f,g,h in {u,d,s,c,b}. Results for the leptonic decay constants of all mesons are also obtained, including scalar and pseudovector states involving heavy quarks. The spectrum of baryons produced by this chiefly algebraic approach reproduces the 64 masses known empirically or computed using lattice-regularised quantum chromodynamics with an accuracy of 1.4(1.2)%. It also has the richness of states typical of constituent-quark models and predicts many baryon states that have not yet been observed. The study indicates that dynamical, nonpointlike diquark correlations play an important role in all baryons; and, typically, the lightest allowed diquark is the most important component of a baryon’s Faddeev amplitude.

Spin- 32 doubly charmed baryon contribution to the magnetic moments of the spin- 12 doubly charmed baryons

We have systematically investigated the magnetic moments of spin-$\frac{1}{2}$ doubly charmed baryons in the framework of the heavy baryon chiral perturbation theory. In this paper, one loop corrections with intermediate spin-$\frac{1}{2}$ and spin-$\frac{3}{2}$ doubly charmed baryon states are considered. The numerical results are calculated to next-to-leading order: $\mu_{\Xi^{++}_{cc}}=0.35\mu_{N}$, $\mu_{\Xi^{+}_{cc}}=0.62\mu_{N}$, $\mu_{\Omega^{+}_{cc}}=0.41\mu_{N}$. Our results may be useful for future experiment and chiral extrapolation of the lattice QCD.

Relativistic Borromean states * *Supported by the National Natural Science Foundation of China (11875002, 11804376), Postdoctoral Innovative Talent Support Program of China (BX20190180). Also supported by the Zhuobai Program of Beihang University

In this work, the existence of Borromean states is discussed for bosonic and fermionic cases in both the relativistic and non-relativistic limits from the 3-momentum shell renormalization. With the linear bosonic model, we check the existence of Efimov-like states in the bosonic system. In both limits a geometric series of singularities is found in the 3-boson interaction vertex, while the energy ratio is reduced by around 70% in the relativistic limit because of the anti-particle contribution. Motivated by the quark-diquark model in heavy baryon studies, we have carefully examined the p-wave quark-diquark interaction and found an isolated Borromean pole at finite energy scale. This may indicate a special baryonic state of light quarks in high energy quark matter. In other cases, trivial results are obtained as expected. In the relativistic limit, for both bosonic and fermionic cases, potential Borromean states are independent of the mass, which means the results would also be valid even in the zero-mass limit.

Studies of excited states of beauty hadrons at CMS

Studies of excited states of beauty mesons and baryons, performed at the CMS Experiment, are presented. The first observation of and states in the invariant mass spectrum is reported as well as the study of excited Λb(5912)0, Λb(5920)0, Λb(6146)0 and Λb(6152)0 baryons decaying to . The analyses use Run-2 data, collected in pp collisions at .

Light-Cone Distribution Amplitudes of Doubly-Heavy Baryons

Doubly-heavy baryons, whose dynamics is determined by a light quark situated in a color field of a static pair of heavy quarks, are investigated. Non-local interpolation currents are introduced and corresponding matrix elements between the baryon and vacuum state are expressed in terms of light-cone distribution amplitudes. Model functions for baryon distribution amplitudes are suggested and their scale dependence is studied in the perturbative QCD framework. The similarity between the heavy meson and doubly-heavy baryon distribution amplitudes is discussed.

Spin-parity assignments of excited -baryons in the Quark-Diquark Model

Recently the LHCb Collaboration have found four baryonic states called Ω b (6316), Ω b (6330), Ω b (6340), and Ω b (6350) in the invariant mass spectrum. Possible spin-parity assignments of these resonances in the Quark-Diquark Model as P-wave baryons are discussed. Parameters of the effective Hamiltonian are determined from the observed spectrum of -baryons and compared with the ones extracted from the mass spectrum of -baryons. Alternative interpretation, in which the three lowest-mass states have the spin-parities JP = 3/2−, 3/2−, 5/2−, predicts an -baryon with the mass M ≃ 6304 MeV which is not yet seen experimentally.

Extended-soft-core baryon-baryon model ESC16. III. S=−2 hyperon-hyperon/nucleon interactions

Background: This is the third of a series of papers on baryon-baryon (BB) interactions, where the baryons are the lowest lying baryon states with spin and parity ${J}^{P}={(1/2)}^{+}$. The paper presents the extended-soft-core (ESC) model ESC16 for BB channels with strangeness $S=\ensuremath{-}2$.Purpose: The aim is to describe the ingredients of the $S=\ensuremath{-}2$ ESC16 potentials, to apply these two-body interactions to BB scattering and via $G$-matrix calculations to hypernuclear systems, and to compare with the presently available experimental information.Methods:The potentials for $S=\ensuremath{-}2$ are based on the SU(3) extension of the ESC potentials for the strangeness $S=0$ and $S=\ensuremath{-}1$ sectors, which are fitted to experimental nucleon-nucleon ($NN$), hyperon-nucleon ($YN$), and hyperon-hyperon ($YY$) data. Flavor SU(3) symmetry is broken only `kinematically' by the masses of the baryons and the mesons. For the $S=\ensuremath{-}2$ channels almost no experimental scattering data exist, and the information from hypernuclei is also rather limited. Nevertheless, in the fit to the $S=0$ and $S=\ensuremath{-}1$ sectors information from the Nagara event and the scarce experimental results on the $\mathrm{\ensuremath{\Xi}}N$ cross sections have been used as (mild) constraints to determine the free parameters in the simultaneous fit of the deuteron and the $NN\ensuremath{\bigoplus}YN$ scattering data. Therefore, the potentials for the $S=\ensuremath{-}2$ sectors are almost completely determined by the fits to the $NN, YN$ data, and SU(3) symmetry.Results: Various properties of the $S=\ensuremath{-}2$ potentials are illustrated by giving results for scattering lengths, bound states, phase parameters, and total cross sections. The well-depth ${U}_{\mathrm{\ensuremath{\Xi}}}$ is calculated and $\mathrm{\ensuremath{\Xi}}N G$-matrix interactions are derived and applied to ${\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}$-capture reactions. Here, a phenomenological $\mathrm{\ensuremath{\Xi}}N$ interaction is added to describe the experiments. Furthermore, the ESC16 model supplemented with phenomenological SU(3) symmetric gaussian interactions is analyzed, and attractive $\mathrm{\ensuremath{\Xi}}N$ interactions are obtained. Combined with three-body forces derived from the ESC meson-pair vertices and the Fujita-Miyazawa interaction, yields good baryon well depths.Conclusions: The ESC16 $S=\ensuremath{-}2$ potentials, with kinematically broken SU(3) symmetry, provide a basis for realistic calculations in nuclear and hypernuclear physics. For a successful description of the well depth's ${U}_{N},{U}_{\mathrm{\ensuremath{\Lambda}}},{U}_{\mathrm{\ensuremath{\Sigma}}}$, and ${U}_{\mathrm{\ensuremath{\Xi}}}$ and hypernuclear $S=\ensuremath{-}2$ reactions phenomenological additions are needed.

Baryonic sources of thermal photons

Thermal radiation of photons and dileptons from hadronic matter plays an essential role in understanding electromagnetic emission spectra in high-energy heavy-ion collisions. In particular, baryons and anti-baryons have been found to be strong catalysts for electromagnetic radiation, even at collider energies where the baryon chemical potential is small. Here, we conduct a systematic analysis of $\pi$- and $\omega$-meson-induced reactions off a large set of baryon states. The interactions are based on effective hadronic Lagrangians where the parameters are quantitatively constrained by empirical information from vacuum decay branchings and scattering data, and gauge invariance is maintained by suitable regularization procedures. The thermal emission rates are computed using kinetic theory but can be directly compared to previous calculations using hadronic many-body theory. The comparison to existing calculations in the literature reveals our newly identified contributions to be rather significant.

Analysis of the 1S and 2S states of Λ Q and Ξ Q with QCD sum rules * *Supported by National Natural Science Foundation (11775079)

In this article, we study the ground states and the first radial excited states of the flavor antitriplet heavy baryon states and with the spin-parity by carrying out operator product expansion up to vacuum condensates of dimension in a consistent way. We observe for the first time that the higher dimensional vacuum condensates play an important role, and obtain very stable QCD sum rules with variations of the Borel parameters for the heavy baryon states. The predicted masses , , and for the first radial excited states , , and , respectively, are in excellent agreement with the experimental data and support assigning , , and to be the first radial excited states of , , and , respectively. The predicted mass for can be confirmed using experimental data in the future.

Hyperons Dalitz decays @ HADES

The electromagnetic transition form factors are an ideal tool to discriminate between various models of hadron structure. However, measuring them is a great experimental challenge, especially in time-like region, that is inaccessible by annihilation experiments. The HADES detector is, thanks to ability to identify di-leptons, an ideal tool to perform measurement in the low q 2 time-like region. This gives access to transitions form factors of excited baryon (N*) states, via Dalitz decays . In this paper I will present a simulation study of a planned experiment, dedicated to measurements of Dalitz decays, produced with a proton beam of kinetic energy Ek = 4.5 GeV. In addition, the current status of the analysis of data collected at Ek = 3.5 GeV will be reported.

New Λb(6072)0 state as a 2S bottom baryon

As a result of continuous developments, the recent experimental searches lead to the observations of new particles at different hadronic channels. Among these hadrons are the excited states of the heavy baryons containing single bottom or charmed quark in their valance quark content. The recently observed $\Lambda_b(6072)^0$ state is one of these baryons and possibly $2S$ radial excitation of the $\Lambda_b$ state. Considering this information from the experiment, we conduct a QCD sum rule analysis on this state and calculate its mass and current coupling constant considering it as a $2S$ radially excited $\Lambda_b$ resonance. For completeness, in the analyses, we also compute the mass and current coupling constant for the ground state $\Lambda_b^0$ and its first orbital excitation. We also consider the $\Lambda_c^+$ counterpart of each state and attain their mass, as well. The obtained results are consistent with the experimental data as well as existing theoretical predictions.

Toward establishing the low-lying P -wave Σb states

In the present work, we analyze the $P$-wave singly-heavy baryon spectrum belonging to $\mathbf{6}_F$ by combining the observations of the heavy baryon states, and restudy the strong decays of the $1P$ wave $\Sigma_b$ states within the $j$-$j$ coupling scheme using the chiral quark model. We obtain that: (i) the structure $\Sigma_b(6097)$ observed in the $\Lambda_b\pi$ final state may arise from the overlapping of $\Sigma_b|J^P=\frac{3}{2}^-,2\rangle$ and $\Sigma_b|J^P=\frac{5}{2}^-,2\rangle$. (ii) The broad structure $\Sigma_b(6072)$ observed in the $\Lambda_b\pi\pi$ final state may arise from the overlapping of $\Sigma_b|J^P=\frac{1}{2}^-,1\rangle$ and $\Sigma_b|J^P=\frac{3}{2}^-,1\rangle$. (iii) The missing state $\Sigma_b|J^P=\frac{1}{2}^-,0\rangle$ is most likely to be a narrow state with a width of $\Gamma\sim10$ MeV, and mainly decays into $\Lambda_b\pi$ channel.

Heavy Baryon Spectroscopy

A review of theoretical predictions for the mass spectra of heavy baryons, obtained within the relativistic quark model and the quark–diquark picture, is given. A detailed comparison is made with experimental data, including recent measurements of the LHCb Collaboration. Good agreement between the theoretical results and the experiment was found. Possible quantum numbers of excited states of heavy baryons are discussed.

Observation of a new baryon state in the {Lambda}_{mathrm{b}}^0{pi}^{+}{pi}^{-} mass spectrum

A new baryon state is observed in the {Lambda}_{mathrm{b}}^0{pi}^{+}{pi}^{-} mass spectrum with high significance using a data sample of pp collisions, collected with the LHCb detector at centre-of-mass energies sqrt{s} = 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The mass and natural width of the new state are measured to bem=6072.3±2.9±0.6±0.2MeV,Γ=72±11±2MeV,\\documentclass[12pt]{minimal}\t\t\t\t\\usepackage{amsmath}\t\t\t\t\\usepackage{wasysym}\t\t\t\t\\usepackage{amsfonts}\t\t\t\t\\usepackage{amssymb}\t\t\t\t\\usepackage{amsbsy}\t\t\t\t\\usepackage{mathrsfs}\t\t\t\t\\usepackage{upgreek}\t\t\t\t\\setlength{\\oddsidemargin}{-69pt}\t\t\t\t\\begin{document}$$ {\\displaystyle \\begin{array}{l}m=6072.3\\pm 2.9\\pm 0.6\\pm 0.2\\ \\mathrm{MeV},\\\\ {}\\Gamma =72\\pm 11\\pm 2\\ \\mathrm{MeV},\\end{array}} $$\\end{document}where the first uncertainty is statistical and the second systematic. The third uncertainty for the mass is due to imprecise knowledge of the {Lambda}_{mathrm{b}}^0 baryon mass. The new state is consistent with the first radial excitation of the {Lambda}_{mathrm{b}}^0 baryon, the Λb(2S)0 resonance. Updated measurements of the masses and the upper limits on the natural widths of the previously observed Λb(5912)0 and Λb(5920)0 states are also reported.

Quark-diquark string tension, excited baryonic resonances and thermal fluctuations

We study the baryonic fluctuations from second to eighth order involving electric charge, baryon number and strangeness below the quark-gluon plasma crossover and numerically known from lattice QCD calculations. By considering a particular realization of the Hadron Resonance Gas model, we provide evidence on the dominant role of quark-diquark degrees of freedom to describe excited baryonic resonances. After proving by means of suitable Polyakov loop correlators that the quark-diquark and the quark-antiquark forces coincide, , we find that the corresponding susceptibilities can be saturated with excited baryonic states in a quark-diquark model picture.

Heavy baryon production with an instanton interaction

Abstract We propose a new reaction mechanism for the study of strange and charmed baryon production. In this mechanism we consider the correlation of two quarks in baryons, so it can be called the two-quark process. As in the previously studied one-quark process, we find large production rates for charmed baryons in comparison with strange baryons. Moreover, the new mechanism causes the excitation of both the $\rho$ mode and the $\lambda$ mode. Using the wave functions for baryons from a quark model, we compute the production rates of various baryon states. We find that the production rates reflect the structure of the wave functions that imply the usefulness of the reactions for the study of baryon structures.

Stringy excited baryons in holographic quantum chromodynamics

Abstract We analyze excited baryon states using a holographic dual of quantum chromodynamics that is defined on the basis of an intersecting D4/D8-brane system. Studies of baryons in this model have been made by regarding them as a topological soliton of a gauge theory on a five-dimensional curved spacetime. However, this allows one to obtain only a certain class of baryons. We attempt to present a framework such that a whole set of excited baryons can be treated in a systematic way. This is achieved by employing the original idea of Witten, which states that a baryon is described by a system composed of $N_c$ open strings emanating from a baryon vertex. We argue that this system can be formulated by an Atiyah–Drinfeld–Hitchin–Manin-type matrix model of Hashimoto–Iizuka–Yi together with an infinite tower of the open string massive modes. Using this setup, we work out the spectra of excited baryons and compare them with the experimental data. In particular, we derive a formula for the nucleon Regge trajectory assuming that the excited nucleons lying on the trajectory are characterized by the excitation of a single open string attached on the baryon vertex.

Nucleons and higher spin baryon resonances: An AdS/QCD configurational entropic incursion

Families of $J^P=1/2+$ nucleons (N(939), N(1440), N(1710), N(1880), N(2100), N(2300)) and $J^P=3/2-$ nucleons (N(1520), N(1700), N(1875) and N(2120)) are scrutinized from the point of view of the configurational entropy (CE). The mass spectra of higher $J^P$ resonances in each one of these families are then obtained when configurational-entropic Regge trajectories, that relate the CE of nucleon families to both their $J^P$ spin and also to their experimental mass spectra, are interpolated. The mass spectra of the next generation of nucleon resonances are then compared to already established baryonic states in PDG. Besides the zero temperature case, the finite temperature analysis is also implemented.