Related papers: Baryon resonances in large $N_c$ QCD
The 1/N expansion of QCD can be used to calculate properties of nucleons and Delta baryons, such as masses, magnetic moments, and pion couplings. The predictions of the 1/N expansion are in excellent agreement with the experimental data.…
We study the properties and couplings of hybrid baryons in the large-$N_c$ expansion. These are color-neutral baryon states which contain in addition to $N_c$ quarks also one constituent gluon. Hybrid baryons with both symmetric and mixed…
Using recently-developed diagrammatic techniques, I derive some general results concerning baryons in the $1/N$ expansion, where $N$ is the number of QCD colors. I show that the spin-flavor relations which hold for baryons in the large-$N$…
Recent work shows not only the necessity of a 1/N_c expansion to explain the observed mass spectrum of the lightest baryons, but also that at least two distinct large N_c expansions, in which quarks transform under either the color…
The generalization of QCD to many colors is not unique; each distinct choice corresponds to a distinct 1/N_c expansion. The familiar 't Hooft N_c -> \infty limit places quarks in the fundamental representation of SU(N_c), while an…
I discuss recent developments in the large N_c treatment of unstable baryon resonances and the scattering amplitudes in which they appear. These include pion photoproduction, extension to three-flavor processes, decoupling of large N_c…
In these lectures, we present the behavior of conventional $\bar{q}q$ mesons, glueballs, and hybrids in the large-$N_{c}$ limit of QCD. To this end, we use an approach based on rather simple NJL-like bound-state equations. The obtained…
We present a diagrammatic analysis of baryons in the $1/N$ expansion, where $N$ is the number of QCD colors. We use this method to show that there are an infinite number of degenerate baryon states in the large-$N$ limit. We also show that…
The spectrum of excited baryons in the $N$ = 2 band is reanalys9 pagesed in the $1/N_c$ expansion method, with emphasis on hyperons. Predictions are made for the classification of these excited baryons into SU(3) singlets, octets and…
We study nonleptonic decays of the orbitally excited, \su6 \rep{70}-plet baryons in order to test the hypothesis that the successes of the nonrelativistic quark model have a natural explanation in the large-$N_c$ limit of QCD. By working in…
We study the mass spectra of excited baryons with the use of the lattice QCD simulations. We focus our attention on the problem of the level ordering between the positive-parity excited state N'(1440) (the Roper resonance) and the…
We review recent progress in our understanding of the nucleon excitation spectrum. Thanks to dedicated efforts at facilities such as ELSA, MAMI and Jefferson Lab, several new nucleon resonances have been discovered, and evidence for…
The original results for the baryon-pion couplings in the large $N_c$ QCD can be understood in a simpler way in the Hartree-Fock picture. The large $N_c$ relation and its $1/N_c$ correction between the heavy baryon-meson coupling and the…
At large number of colors, N_c quarks in baryons are in a mean field of definite space and flavor symmetry. We write down the general Lorentz and flavor structure of the mean field, and derive the Dirac equation for quarks in that field.…
The calculation of the spectrum of QCD is key to an understanding of the strong interactions, and vital if we are to capitalize on the experimental study of the spectrum. In this paper, we describe progress towards understanding the…
Progress in extracting excited-state baryon masses in lattice QCD using large sets of spatially-extended operators is presented. The use of stochastic estimates of all-to-all quark propagators with variance reduction techniques is…
Our progress in computing the spectrum of excited baryons and mesons in lattice QCD is described. Sets of spatially-extended hadron operators with a variety of different momenta are used. A new method of stochastically estimating the…
A simple procedure within the $1/N_c$ expansion method where all the $N_c$ quarks are treated on the same footing has been found successful in describing mixed symmetric negative parity baryon states belonging to the $[{\bf 70},\ell^-]$…
We present a phenomenological analysis of the strong couplings of the negative-parity L=1 baryons from the perspective of the large-$N_c$ expansion. In the large-$N_c$ limit the mass spectrum and mixing pattern of these states are…
We show that excited baryons in large N_c QCD form multiplets, within which masses are first split at O(1/N_c). The dominant couplings of resonances to various mesons are highly constrained: The N(1535) decays at leading 1/N_c order…