相关论文: Delta electroproduction in a chiral bag model appr…
Helicity amplitudes for the $\gamma^* N \to \Delta$ transition are calculated using the cloudy bag model. A correction for center-of-mass motion is carried out using a modified Peierls-Thouless projection method. This reduces the magnitude…
We review some basic properties of the N-Delta transition axial amplitudes and relate them to the strong pi-N-Delta form-factor. In models with the pion cloud we derive a set of constraints on the pion wave function which guaranty the…
The multipole amplitudes for the N - Delta electromagnetic transition are computed in the framework of the linear sigma model and the chiral chromodielectric model for small and moderate photon virtualities. The models include quark and…
We discuss electro-magnetic and weak axial N-Delta transition amplitudes in the linear sigma-model and the Cloudy-Bag Model as typical representatives of chiral quark models. We show that good qualitative understanding of the transition can…
We present a method to calculate directly the K-matrices for the pion electro-production processes in the framework of chiral quark models which allows for a clean separation of the resonant amplitudes from the background. The method is…
By applying a unitary transformation method, we have derived the leading-order corrections on the effective Hamiltonian of a dynamical model developed in Phys. Rev. C54, 2660 (1996) for electromagnetic pion production reactions. The…
We study the axial amplitudes for the N-Delta transition in models with quarks and chiral mesons. A set of constraints on the pion field is imposed which enforces PCAC and the off-diagonal Goldberger-Treiman relation. The quark contribution…
We investigate the neutral pion photoproduction on the proton near threshold in covariant chiral perturbation theory with the explicit inclusion of Delta degrees of freedom. This channel is specially sensitive to chiral dynamics and the…
Kaon production cross sections in nucleon-nucleon, nucleon-delta and delta-delta interactions are studied in a boson exchange model. For the latter two interactions, the exchanged pion can be on-mass shell, only contributions due to a…
Heavy baryon chiral perturbation theory ($\chi$PT), where the $\Delta$ resonance is included, is used in order to examine the axial charged-current component of the weak interaction process at low neutrino energies. At leading chiral order…
A covariant spectator constituent quark model is applied to study the gamma N -> Delta(1600) transition. Two processes are important in the transition: a photon couples to the individual quarks of the Delta(1600) core (quark core), and a…
We calculate chiral corrections to the octet axial currents through ${\cal O}(p^3)$ using baryon chiral perturbation theory (BCPT). The relativistic BCPT framework allows one to sum an infinite series of recoil corrections at a given order…
The impact of the short-range $N\Delta$ interaction on the pion photoproduction processes off the deuteron in the $\Delta$-resonance region is studied in the framework of recently proposed dressed-bag model. A common dressing procedure for…
We study the N-Delta-gamma transition in the Dyson-Schwinger approach. The nucleon and Delta baryons are treated as quark-diquark bound states, where the ingredients of the electromagnetic transition current are computed self-consistently…
We apply a coupled-channel formalism incorporating quasi-bound quark-model states to calculate pion scattering into eta N, K Lambda and K Sigma channels, as well eta p, eta n, K+Lambda, and K0Sigma+ photo-production processes. The…
We calculate magnetic moments of light baryons and N -> Delta gamma transition characteristics using a manifestly Lorentz covariant chiral quark approach for the study of baryons as bound states of constituent quarks dressed by a cloud of…
The dynamical model of pion electroproduction has been extended to investigate the weak pion production reactions. The predicted cross sections of neutrino-induced pion production reactions are in good agreement with the existing data. We…
Using a chiral unitary approach for meson-baryon scattering in the strangeness zero sector, where the $N^*(1535)$ resonance is dynamically generated, we study the reactions $\gamma p \to \pi^0 \eta p$ and $\gamma p \to \pi^0 K^0 \Sigma^+$…
We apply the perturbative chiral quark model to the gamma N -> Delta transition. The four momentum dependence of the respective transverse helicity amplitudes A(1/2) and A(3/2) is determined at one loop in the pseudoscalar Goldstone boson…
The process of pion axioproduction, $aN\to\pi N$, with an intermediate $\Delta$ resonance is analyzed using baryon chiral parturbation theory. The $\Delta$ resonance is included in two ways: First, deriving the $a\Delta N$-vertices, the…