Related papers: Hypercentral Constituent Quark Model with a Meson …
We study the electromagnetic structure of the nucleon within a hybrid constituent-quark model that comprises, in addition to the $3q$ valence component, also a $3q$+$\pi$ non-valence component. To this aim we employ a Poincar\'e-invariant…
We present estimates from the covariant spectator quark model for the electromagnetic transition form factors for the resonances $N(1440)\frac{1}{2}^+$, $N(1535)\frac{1}{2}^-$, $N(1520)\frac{3}{2}^-$ and $\Delta(1232)\frac{3}{2}^+$, at…
The transition form factors describing the semileptonic decays of heavy pseudoscalar mesons are investigated within a relativistic constituent quark model formulated on the light-front. For the first time, the form factors are calculated in…
The constituent quark model based on a hypercentral approach takes into account three-body force effects and standard two-body potential contributions. The quark potential contains a hypercentral interaction, to which a hyperfine term is…
A formalism for the relativistic description of hadron decays within the constituent quark model is presented. First, hadron amplitudes of the light--cone constituent quark model, in particular the weak transition form factors at spacelike…
This talk presents issues pertaining to the quark structure of the pion within QCD, both from the theoretical and from the experimental point of view. We review and discuss the pion-photon transition form factor and the pion's…
We describe the effective heavy meson lagrangian for S- and P-wave heavy-light mesons in terms of a model based on meson-quark interactions, where mesonic transition amplitudes are represented by diagrams with heavy mesons attached to loops…
We examine the electromagnetic properties of the Delta(1232) resonance within the self-consistent chiral quark-soliton model. In particular we present the Delta form factors of the vector-current GE0, GE2 and GM1 for a momentum-transfer…
We report new p$(\vec{e},e^\prime p)\pi^\circ$ measurements in the $\Delta^{+}(1232)$ resonance at the low momentum transfer region utilizing the magnetic spectrometers of the A1 Collaboration at MAMI. The mesonic cloud dynamics are…
We review some results obtained by the Coimbra-Ljubljana collaboration that reveal the important role of the pion cloud in the low- and intermediate-energy nucleon and delta resonances.
We discuss the dressing of constituent quarks with a pseudoscalar meson cloud within the effective chiral quark model. SU(3) flavor symmetry breaking effects are included explicitly. Our results are compared with those of the traditional…
A parameter-free evaluation of the $N - P_{11}(1440)$ electromagnetic transition form factors is performed within a light-front constituent quark model, using for the first time the eigenfunctions of a mass operator which generates a large…
We show that constraints from perturbative QCD calculations play a role in the nucleon to Delta(1232) electromagnetic transition even at moderate momentum transfer scales. The pQCD constraints, tied to real photoproduction data and…
The nucleon polarizabilities alpha(E) and beta(M) are studied in the context of the perturbative chiral quark model. We demonstrate that meson cloud effects are sufficient to explain the electric polarizability of nucleon. Contributions of…
In this work we explore the effect of pion cloud contributions to the mass of the nucleon and the delta baryon. To this end we solve a coupled system of Dyson-Schwinger equations for the quark propagator, a Bethe-Salpeter equation for the…
We calculate the strong couplings of pions to the Delta(1232) resonance using a QCD parameterization method that includes in addition to the usual one-quark also two-quark and previously uncalculated three-quark operators. We find that…
Predictions obtained with a confining, symmetry-preserving treatment of a vector-vector contact interaction at leading-order in a widely used truncation of QCD's Dyson-Schwinger equations are presented for \Delta and \Omega baryon elastic…
Soft Two-body potentials between the constituent quarks of the nucleon are derived using harmonic oscillator, i.e. gaussian, quark wave-functions. The gaussian wave-functions are very suited for applications with the ESC soft-core…
The recent investigation on various form factors of the nucleon is reviewed in the framework of the SU(3) chiral quark-soliton model. The results for the electromagnetic and scalar form factors are in remarkable agreement with experimental…
We study the octet to decuplet baryon electromagnetic transitions using the covariant spectator quark model, and predict the transition magnetic dipole form factors for those involving the strange baryons. Utilizing SU(3) symmetry, the…