相关论文: Baryon Mass Splittings in the 1/N_c Expansion
The masses of baryons and heavy quark baryons are studied analytically in an expansion in 1/N, SU(3) flavor symmetry breaking and heavy-quark symmetry breaking. The measured baryon masses are in striking agreement with the 1/N hierarchy.
The masses of baryons containing a single heavy quark are studied in a combined expansion in $1/m_Q$, $1/N_c$ and $SU(3)$ flavor symmetry breaking. Heavy quark baryon mass splittings are related to mass splittings of the octet and decuplet…
The mass spectrum of the positive parity [56,2^+] baryons is studied in the 1/Nc expansion up to and including O(1/Nc) effects with SU(3) symmetry breaking implemented to first order. A total of eighteen mass relations result, several of…
The masses of heavy quark baryons are studied in an expansion in 1/N_c, SU(3) flavor symmetry breaking, and heavy-quark symmetry breaking. Very accurate model-independent mass relations are obtained for charm and bottom baryons.
The 1/N_c expansion provides a theoretical method for analyzing the spin-flavor symmetry properties of baryons in QCD that is quantitative, systematic and predictive. An exact spin-flavor symmetry exists for large-N_c baryons, whereas for…
The baryon mass operator is studied within a combined expansion in $1/N_c$ and perturbative $SU(3)$ flavor symmetry breaking, where $N_c$ denotes the number of quark charges. Flavor projection operators are used to classify the baryon…
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-$N$…
The 1/N_c expansion of QCD with N_c=3 has been successful in explaining a wide variety of QCD phenomenology. Here I focus on the contracted spin-flavor symmetry of baryons in the large-N_c limit and deviations from spin-flavor symmetry due…
1/N_c baryon mass relations are compared with lattice simulations of baryon masses using different values of the light-quark masses, and hence different values of SU(3) flavor-symmetry breaking. The lattice data clearly display both the…
The masses of positive $[{\bf 70},0^+]$ and $[{\bf 70},2^+]$ nonstrange and strange baryons are calculated in the $1/N_c$ expansion. The approach is based on the separation of a system of $N_c$ quarks into an excited core and an excited…
The effective theory for baryons with combined 1/Nc and chiral expansions is analyzed for non-strange baryons. Results for baryon masses and axial couplings are obtained in the small scale expansion, to be coined as the \xi-expansion, in…
The masses of excited states of mixed orbital symmetry of nonstrange and strange baryons belonging to the lowest $[{\bf 70},1^-]$ multiplet are calculated in the $1/N_c$ expansion to order $1/N_c$ with a new method which allows to…
The magnetic moments and transition magnetic moments of the ground state baryons are analyzed in an expansion in 1/N_c, SU(3) flavor symmetry breaking and isospin symmetry breaking. There is clear evidence in the experimental data for the…
The properties of baryons can be computed in a systematic expansion in $1/N_c$, where $N_c$ is the number of colors. Recent results on the axial couplings and masses of baryons (for the case of three flavors) are presented. The results give…
We consider flavor breaking in the the octet and decuplet baryon masses at second order in large-$N$ chiral perturbation theory, where $N$ is the number of QCD colors. We assume that $1/N \sim 1/N_F \sim m_s / \Lambda \gg m_{u,d}/\Lambda,…
A systematic expansion in 1/N is constructed for baryons in QCD. Predictions of the 1/N expansion at leading and subleading order for baryon axial current coupling constant ratios such as F/D, baryon masses and magnetic moments are derived.…
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…
Baryon Chiral Perturbation Theory combined with the $1/N_c$ expansion is implemented for three flavors. Baryon masses, vector charges and axial vector couplings are studied to one-loop and organized according to the $\xi$-expansion, in…
The excited baryon masses are analyzed in the framework of the $1/N_c$ expansion using the available physical masses and also the masses obtained in lattice QCD for different quark masses. The baryon states are organized into irreducible…
Recent discoveries of the Xi_b, Sigma_b and Sigma_b^* baryons at the Tevatron are in good agreement with model-independent mass predictions made a decade ago based on a combined expansion in 1/N_c, 1/m_Q and SU(3) flavor symmetry breaking.…