Related papers: N* Properties from the 1/N_c Expansion
A recently proposed modified perturbation expansion for QCD is employed to evaluate the quark self-energies. Results of the order of 1/3 of the nucleon mass are obtained for the effective masses of the up and down quarks in a first…
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…
We investigate properties of the color space of $SU(N_c)$ gauge theories in the limit of small number of colors $(N_c \to 0)$ and large number of flavors. More generally, we introduce a rescaling of $\alpha_s$ and $n_f$ which assigns a…
We summarize some recent results on the structure of QCD at very high baryon density.
The chiral Lagrangian for baryons is formulated in an expansion in 1/N_c. The chiral Lagrangian implements the contracted spin-flavor symmetry of large-N_c baryons as well as nonet symmetry of the leading planar diagrams. Large-N_c…
We use one-flavour QCD ($N_c=3$) as a proxy to understand $\mathcal{N}=1$ SYM. For our simulations, we use tree-level improved Wilson fermions and Symanzik improved gauge action. The hadron spectrum is obtained by using LapH smearing for…
We use the $1/N_c$ expansion of QCD to 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. We find that the…
Recent results of meson photo-production at the existing electron machines with polarized real photon beams and the measurement of polarization observables of the final state baryons have provided high precision data that led to the…
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…
I comment on progress of lattice QCD techniques and calculations. Recent results on pentaquark masses as well as of the spectrum of excited baryons are summarizned and interpreted. The present state of calculations of quantities related to…
We briefly discuss the large Nc picture for excited baryons, present a new method for the calculation of matrix elements and illustrate it by computing the strong decays of heavy exotic states.
The production of $(b\bar{c})$-quarkonium ($\bar{B}_c$ meson and its excited states) or $(c\bar{b})$-quarkonium ($B_c$ meson and its excited states) via top quark $t$ or top anti-quark $\bar{t}$ decays, $t\to (b\bar{c})+c+W^+$ or…
This paper studies baryons and baryonic matter in the combined large N_c and heavy quark mass limits of QCD in 1+1 dimension. In this non-relativistic limit, baryons are composed of N_c quarks that interact, at leading order in N_c, through…
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…
Recent interest in novel phases in high density QCD motivates the study of high density supersymmetric QCD (SQCD), where powerful exact results for supersymmetric gauge theories can be brought to bear in the strongly coupled regime. We…
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 consider in detail the mass operator analysis for the nonstrange L=1 excited baryons in large N_c QCD. We present a straightforward procedure for constructing the large N_c baryon wavefunctions, and provide complete analytic expressions…
The composite nature of baryons manifests itself in the existence of a rich spectrum of excited states, in particular in the important mass region 1-2 GeV for the light-flavoured baryons. The properties of these resonances can be identified…
We present preliminary results about topology and several other quantities at non-zero baryon density and finite temperature in full QCD with N_c=2.
Exotic mesons with quantum numbers of a hybrid ($\bar{q} q g$) such as $J^{PC} = 1^{-+}$are shown to exist as narrow resonant states in the large $N_c$ limit of QCD. The width of these states is proportional to $1/N_c$. Possible…