相关论文: Electromagnetic processes and the diquark model
Nucleon elastic and transition form factors are analyzed in the framework of a collective model of baryons. Effects of meson cloud couplings and relativistic corrections are considered.
A perspective on the contemporary use of Dyson-Schwinger equations, focusing on some recent phenomenological applications: a description and unification of light-meson observables using a one-parameter model of the effective quark-quark…
In this contribution, an approach for a unified description of the pion electromagnetic form factor, in the space- and time-like regions, within a constituent quark model on the light front, will be reviewed. Our approach is based on i) the…
We discuss various topics in the theory of heavy baryon decays. Among these are recent applications of the Relativistic Three Quark Model to semileptonic, nonleptonic, one-pion and one-photon transitions among heavy baryons, new higher…
We investigate the electroweak form factors and semileptonic decay rates of mesons using the constituent quark model based on the light-front degrees of freedom. Our results demonstrate the broader applicability of light-front approach…
The elastic and transition electromagnetic form factors of mesons are investigated within a light-front constituent quark model. The general formulae for the space-like matrix elements of the one-body component of the electromagnetic…
In this thesis a general relativistic framework for the calculation of the electroweak structure of mesons of arbitrary constituent-quark masses is presented. The physical processes in which the structure is measured, i.e. electron-meson…
Nonperturbative effects in exclusive reactions $B\to K^{(*)}ll$ are discussed. Form factors which describe the main long-distance contribution to the meson transition amplitude are calculated within the dispersion formulation of the quark…
The proton and neutron electromagnetic form factors and the nucleon axial form factor have been calculated in the Goldstone-boson exchange constituent-quark model within the point-form approach to relativistic quantum mechanics. The…
An important goal of ongoing and future experiments is to explore spectra and transition form factors of baryons with non-zero strangeness. Of particular interest is the transition form factor$\gamma^{(*)} \Sigma^0 \rightarrow \Lambda$ in…
We derive covariant wave functions for hadrons composed of two constituents for arbitrary Lorentz boosts. Focussing explicitly on baryons as quark-diquark systems, we reduce their manifestly covariant Bethe-Salpeter equation to covariant…
The relativistic interacting quark-diquark model of baryons, recently developed, is here extended to introduce a spin-isospin transition interaction into the mass operator. The refined version of the model is used to calculate the non…
We discuss the recent experimental results on the ratio bertween the electric and magnetic proton form factors and how they can be described by the hypercentral Constituent Quark Model.
There has been considerable progress in the study of the electromagnetic form factors of baryons in the timelike region, through electron-positron scattering reactions ($e^+ e^- \to B \bar B$), in the last two decades. Timelike experiments…
A phenomenological Lagrangian approach is employed to study the electromagnetic properties of the deuteron. The deuteron is regarded as a weakly bound state of the proton and neutron. We construct a general form for the electromagnetic one-…
The proton form factor, two-photon annihilations into $p\bar{p}$ as well as exclusive charmonium decays are critically examined. It will be argued that the standard perturbative QCD analysis of these reactions fails, i.e. the need for…
The magnetic moments and radiative decay widths of heavy baryons belong to a class of interesting experimental observables which provide direct information about the dynamics of strong interactions as well as the properties and the…
Photons and dileptons are being used to probe the properties of nuclear and quark-gluon matter at high energy densities. This is an area where theory and experiment are driving each other to obtain solid results. However, it is important to…
After a brief introduction into the basic ingredients of electroweak theory as a spontaneously broken local, non-Abelian gauge symmetry, the general properties of the electromagnetic current and two-photon operators are discussed. The…
A simple quark-diquark model for the baryons is constructed as a partial solution to the well known missing resonances problem. A complete classification of the baryonic states in the quark-diquark framework is given and the spectrum is…