We consider evolution equations describing the scale dependence of the wave function of a baryon containing an infinitely heavy quark and a pair of light quarks at small transverse separations, which is the QCD analogue of the helium atom.The evolution equations depend on the relative helicity of the light quarks. For the aligned helicities, we find that the equation is completely integrable, that is it has a nontrivial integral of motion, and obtain exact analytic expressions for the eigenfunctions and the anomalous dimensions. The evolution equation for anti-aligned helicities contains an extra term that breaks integrability and creates a "bound state" with the anomalous dimension separated from the rest of the spectrum by a finite gap. The corresponding eigenfunction is found using numerical methods. It describes the momentum fraction distribution of the light quarks in, e.g., $Λ_b$-baryon at large scales.
Due to integrability, baryon-baryon scattering in the massless Gross-Neveu model at large N features only forward elastic scattering. A bare mass term breaks integrability and is therefore expected to induce backward elastic scattering as well as inelastic reactions. We confirm these expectations by a study of baryon-baryon scattering in the massive Gross-Neveu model near the non-relativistic limit. This restriction enables us to solve the time-dependent Hartree-Fock equations with controlled approximations, using a combination of analytical methods from an effective field theory and the numer…
It was found that renormalization group equations in the heavy-quark effective theory (HQET) for the operators involving one effective heavy quark and light degrees of freedom are completely integrable in some cases and are related to spin chain models with the Hamiltonian commuting with the nondiagonal entry $C(u)$ of the monodromy matrix. In this work we provide a more complete mathematical treatment of such spin chains in the QISM framework. We also discuss the relation of integrable models that appear in the HQET context with the large-spin limit of integrable models in QCD with light quar…
To see whether heavy baryon and anti-baryon can form a bound state, the heavy baryonium, we study the interaction potential between them in terms of heavy baryon perturbation theory. The obtained potential is applied to calculate the heavy baryonium masses by solving Schrödinger equation. We find it is true that the heavy baryonium may exist in a reasonable choice of input parameters. The uncertainties remaining in the potential and their influences on the heavy baryonium mass spectrum are discussed.
Using the calculated values of the strong coupling constants of the heavy sextet spin-3/2 baryons to sextet and antitriplet heavy spin-1/2 baryons with light mesons within the light cone QCD sum rules method, and vector meson dominance assumption, the radiative decay widths are calculated. These widths are compared with the "direct" radiative decay widths predicted in the framework of the light cone QCD sum rules.
In this talk, we give a short review of our recent works on studying the singly heavy baryon, doubly heavy baryon, and triply heavy baryon spectra from QCD sum rules.
This paper studies the leading chiral corrections to heavy quark-diquark symmetry predictions for doubly heavy baryon semileptonic decay form factors. We derive the coupling between heavy diquarks and weak current in the limit of heavy quark-diquark symmetry, and construct the chiral Lagrangian for doubly heavy baryons coupled to weak current. We evaluate chiral corrections to doubly heavy baryon zero-recoil semileptonic decay for both unquenched and partially quenched QCD. This theory is used to derive chiral extrapolation expressions for measurements of form factors of doubly heavy baryon ze…
The heavy spin--3/2 baryon--heavy spin--1/2 baryon vertices with light vector mesons are studied within the light cone QCD sum rules method. These vertices are parametrized in terms of three coupling constants. These couplings are calculated for all possible transitions. It is shown that correlation functions for these transitions are described by only one invariant function for every Lorenz structure. The obtained relations between the correlation functions of the different transitions are structure independent while explicit expressions of invariant functions depend on the Lorenz structure.
This paper explores properties of baryons and finite density baryonic matter in an artificial world in which Nc, the number of colors, is large and the quarks of all species are degenerate and much larger than Λ_QCD. It has long been known that in large Nc QCD, baryons composed entirely of heavy quarks are accurately described in the mean-field approximation. However, the detailed properties of baryons in the combined large Nc and heavy quark limits have not been fully explored. Here some basic properties of baryons are computed using a variational approach. At leading order in both the large …
The theoretical analysis of production, lifetime, and decays of doubly heavy baryons is presented. The lifetime of $Ξ_{cc}^{++}$ baryon recently measured by the LHCb Collaboration is used to estimate the lifetimes of other doubly heavy baryons. The production and the possibility of observation of $Ξ_{bc}$ baryon at LHC are discussed.
In this article, we study the ${3\over 2}^+$ heavy and doubly heavy baryon states $Ξ^*_{cc}$, $Ω^*_{cc}$, $Ξ^*_{bb}$, $Ω^*_{bb}$, $Σ_c^*$, $Ξ_c^*$, $Ω_c^*$, $Σ_b^*$, $Ξ_b^*$ and $Ω_b^*$ by subtracting the contributions from the corresponding ${3\over 2}^-$ heavy and doubly heavy baryon states with the QCD sum rules, and make reasonable predictions for their masses.
The relativistic six-quark equations are found in the framework of the dispersion relation technique. The charmed baryonia $B\bar B$ are constructed without the mixing of the quarks and antiquarks. The relativistic six-quark amplitudes of the heavy baryonia are calculated. The poles of these amplitudes determine the masses of baryonia. 8 masses of charmed baryonia are predicted.
In this article, we study the ${1\over 2}^+$ doubly heavy baryon states $Ω_{QQ}$ and $Ξ_{QQ}$ by subtracting the contributions from the corresponding ${1\over 2}^-$ doubly heavy baryon states with the QCD sum rules, and make reasonable predictions for their masses. Those doubly heavy baryon states maybe observed at the Tevatron, the LHCb and the PANDA.
Masses of heavy baryons are calculated in the relativistic quark-diquark picture. Obtained results are in good agreement with available experimental data including recent measurements by the LHCb Collaboration. Possible quantum numbers of excited heavy baryon states are discussed.
We study the semileptonic decays of double heavy baryons using a manifestly Lorentz covariant constituent three-quark model. We present complete results on transition form factors between double-heavy baryons for finite values of the heavy quark/baryon masses and in the heavy quark symmetry limit which is valid at and close to zero recoil. Decay rates are calculated and compared to each other in the full theory, keeping masses finite, and also in the heavy quark limit.
The triply heavy flavour baryons are studied using the Quark-diquark description of the three-body system. The confinement potential for present study of triply heavy flavour baryons is assumed as coulomb plus power potential with power index $ν$. We have solved Schrodinger equation numerically to calculate the masses of triply heavy flavour baryons. The masses and magnetic moments of triply heavy flavour baryons are computed for different power indices, $ν$, starting from 0.4 to 1.0. The predicted masses and magnetic moments are in good agreement with other theoretical predictions.
In the framework of diquark model for production we discuss the yields and observation prospects for excited states of doubly heavy baryons at LHC kinematic conditions.
Transition decay widths by one-pion emissions for excited heavy-baryons with a single heavy (charm and bottom) quark are investigated by following the heavy-quark symmetry and its breaking effects at ${\cal O}(1/M)$ for a heavy-baryon mass $M$. Based on the heavy-baryon effective theory, interaction Lagrangian for the heavy baryons with axial-vector current induced by a pion is constructed. It is presented that the transition decay widths up to ${\cal O}(1/M)$ in several channels are constrained. The results will be useful in experimental study of excited heavy-baryons.
Baryons with three heavy quarks are the last missing pieces of the lowest-lying baryon multiplets in the quark model after the discovery of doubly heavy baryons. In this work, we study nonleptonic weak decays of triply heavy baryons $Ω_{ccc}^{++}$, $Ω_{bbb}^{-}$, $Ω_{ccb}^{+}$, and $Ω_{cbb}^{0}$. Decay amplitudes for various processes have been parametrized in terms of the SU(3) irreducible nonperturbative amplitudes. A number of relations for the partial decay widths can be deduced from these results that can be examined in future. Some decay channels and cascade decay modes which likely to b…
The magnetic moments of the negative parity, spin-1/2 baryons containing single heavy quark are calculated. The pollution that occur from the transitions between positive and negative parity baryons are removed by constructing the sum rules from different Lorentz structures.
The magnetic moments of heavy sextet $J^P = {1\over 2}^+$ baryons are calculated in framework of the light cone QCD sum rules method. Linearly independent relations among the magnetic moments of these baryons are obtained. The results for the magnetic moments of heavy baryons obtained in this work are compared with the predictions of the other approaches.
We calculate the coupling constants between the light vector mesons and heavy baryons within the framework of the light-cone QCD sum rule in the leading order of heavy quark effective theory. Most resulting sum rules are stable with the variations of the Borel parameter and the continuum threshold. The extracted couplings will be useful in the study of the possible heavy baryon molecular states.
