Related papers: Infrared regularization with vector mesons and bar…
In the present paper we extend the Schwinger model of the nucleon to the inclusion of loop corrections. Starting from a chiral model of nucleon and delta for the mesons $\pi,\rho$ and $A_1$ we extend our nonperturbative sefconsistent…
We study the imaginary parts of the isoscalar electromagnetic and isovector axial form factors of the nucleon close to the $3\pi$-threshold in covariant baryon chiral perturbation theory. At the two-loop level, the contributions arising…
We study the spectra of mesons and baryons, composed of light quarks, in the framework of a semirelativistic potential model including instanton induced forces. We show how a simple modification of the instanton interaction in the baryon…
Integral equations for meson-baryon scattering amplitudes are obtained by utilizing time-ordered perturbation theory for a manifestly Lorentz-invariant formulation of baryon chiral perturbation theory. Effective potentials are defined as…
Meson loop corrections to baryon axial currents are computed in the 1/N expansion. It is already known that the one-loop corrections are suppressed by a factor 1/N; here it is shown that the two-loop corrections are suppressed by (1/N)^2.…
Using baryon chiral perturbation theory including vector mesons, we analyse various continuum contributions to the isoscalar electromagnetic spectral functions of the nucleon induced by the leading order couplings.
We calculate the electromagnetic and the axial form factors of the nucleon within the framework of light cone sum rules (LCSR) to leading order in QCD and including higher twist corrections. In particular we motivate a certain choice for…
A general and systematic regularization is developed for the exact solitonic form factors of exponential operators in the (1+1)-dimensional sine-Gordon model by analytical continuation of their integral representations. The procedure is…
This lecture comprises some recent developments concerning the description of baryons as topological solitons in effective chiral meson theories. In the first part one-loop corrections to the classical tree approximation are discussed. This…
Employing the Bethe-Salpeter formalism, we present a computation of the space-like baryonic form factor for the pion and kaon. In the exact isospin-symmetric limit this observable is forbidden by $G$-parity, so that any nonzero signal…
We propose a novel matrix regularization for tensor fields. In this regularization, tensor fields are described as rectangular matrices and both area-preserving diffeomorphisms and local rotations of the orthonormal frame are realized as…
We present the application of the method of light-cone sum rules to the determination of baryonic form factors at intermediate momentum transfer. After reviewing the current status of this field we give some outlook on possible future…
We continue our investigation of the Z_N-Baxter-Bazhanov-Stroganov model using the method of separation of variables [nlin/0603028]. In this paper we calculate the norms and matrix elements of a local Z_N-spin operator between eigenvectors…
We address the issue of a consistent power counting scheme in manifestly Lorentz-invariant baryon chiral perturbation theory. We discuss the inclusion of vector mesons in the calculation of the nucleon electromagnetic form factors. We…
The nucleon axial vector form factor is investigated in a light-cone quark spectator diquark model, in which Melosh rotations are applied to both the quark and vector diquark. It is found that this model gives a very good description of…
We analyze the axial-vector form factors of the nucleon hyperon system in a model with mass dependent quark spin polarizations. This mass dependence is deduced from an earlier analysis\cite{jlhs,jlhs2} of magnetic moment data, and implies…
We investigate the relation between the topology of a nucleon and its spin composition. We approach this question in (1+1) dimensional single-flavor QCD with a large number of color. In this limit the theory can be shown to be dual to the…
The baryon axial currents are calculated at one-loop order in heavy baryon chiral perturbation theory by employing both a cutoff and dimensional regularization. Data from the semileptonic baryon decays is used to perform a least-squares fit…
Differential regularization is used to investigate the one-loop quantum corrections to Chern-Simons-Maxwell spinor and scalar electrodynamics. We illustrate the techniques to write the loop amplitudes in coordinate space. The short-distance…
We developed a method to analyze the polarization correlations of two baryons $B_{1}\bar{B}_{2}$ with various spin combinations in the annihilation process. We established spin density matrices for arbitrary spins in standard and Cartesian…