Related papers: Large N_c
The chiral and $1/N_c$ expansions are combined in the description of low energy baryons. The combination furnishes a better behaved expansion, consequence of exactly eliminating large terms that violate the $1/N_c$ expansion and which are…
We review results for the mass spectrum of orbitally excited baryons obtained in the $1/N_c$ expansion. We show the dependence of various contributions to the mass operator as a function of the excitation energy.
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 $[{\bf 70},\ell^-]$…
Tree amplitudes for baryon-pion scattering are studied in the 1/N_c expansion. Generalized large-N_c consistency conditions are obtained to all orders in baryon mass splittings. For baryons with spin J ~ O(1), the leading order in N_c tree…
We take into account the $1/m_Q$ corrections upto $1/N_c$ order in the heavy-meson-soliton bound state approach for heavy baryons. With these corrections, the mass spectra of baryons with $c$-quark as well as of those with $b$-quark are…
We present a lattice simulation study of large $N_c$ regularities of meson and baryon spectroscopy in $SU(N_c)$ gauge theory with two flavors of dynamical fundamental representation fermions. Systems investigated include $N_c=2$, 3, 4, and…
The mass splittings of the baryons belonging to the $[{\bf 70},1^-]$-plet are derived by using a simple group theoretical approach to the matrix elements of the mass formula. The basic conclusion is that the first order correction to the…
We use the $1/N_c$ expansion of QCD to analyse the spectrum of positive parity resonances with strangeness $S = 0, -1, -2$ and -3 in the 2--3 GeV mass region, supposed to belong to the $[\textbf{56},4^+]$ multiplet. The mass operator is…
We study the structure of QCD at very large baryon density for an arbitrary number of flavors $N_f$. We provide evidence that for any number of flavors larger than $N_f=2$ chiral symmetry remains broken at asymptotically large chemical…
The mass spectrum of charmed and bottom baryons has been computed on anisotropic lattices using quenched lattice nonrelativistic QCD. Masses are extracted by using mass splittings which are more accurate than masses obtained directly by…
We generate a complete basis of magnetic moment operators for the N_c = 3 ground-state baryons in the 1/N_c expansion, and compute and tabulate all associated matrix elements. We then compare to previous results derived in the literature…
Using the $1/N_c$ expansion of QCD we analyze the spectrum of positive parity resonances with strangeness $S = 0, -1, -2$ and -3 in the 2-3 GeV mass region, supposed to belong to the $[\textbf{56},4^+]$ multiplet. The mass operator is…
The structure of the 1/Nc expansion for the baryon distribution amplitude in QCD is tested using quark models. Earlier conjectures about this structure based on the evolution equation and on the soft-pion theorem are confirmed by the model…
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…
We study the chiral expansion of the baryon octet and decuplet masses in the isospin limit. It is illustrated that a chiral expansion of the one-loop contributions is rapidly converging up to quark masses that generously encompasses the…
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…
We match the non-relativistic quark model, with both flavor dependent and flavor independent effective quark-quark interactions, to the spin-flavor operator basis of the 1/Nc expansion for the L=1 non-strange baryons. We obtain analytic…
We investigate the mass differences of charm and bottom heavy baryons, using MILC lattice gauge configurations with 2+1 dynamical sea quark flavors. We extend our previous work to three lattice spacings: fine (a~0.09), coarse (a~0.12), and…
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 status of exotic baryons is analyzed in the limit of a large number of colors Nc. Several toy models reproducing the main features of the large-Nc QCD are studied in order to clarify the recent controversy concerning the consistency of…