Related papers: Electromagnetic nucleon-delta transition in the pe…
Within the one-loop approximation of baryon chiral perturbation theory we calculate all one-pion and two-pion exchange contributions to the nucleon-nucleon interaction. In fact we construct the elastic NN-scattering amplitude up to and…
We present predictions for the $\gamma^\ast N \to N^\ast$ helicity amplitudes, where $N^\ast$ is a member of the $[70,1^-]$ supermultiplet. We combine the results from the single quark transition model for the helicity amplitudes with the…
We develop a generalized version of heavy-baryon chiral perturbation theory to describe pion-nucleon scattering in a kinematic domain that extends continuously from threshold to the delta-isobar peak. The $P$-wave phase shifts are used to…
We investigate the critical scaling of the quark propagator of N_f=2 QCD close to the chiral phase transition at finite temperature. We argue that it is mandatory to take into account the back-reaction effects of pions and the sigma onto…
The electromagnetic nucleon to Delta transition form factors are evaluated using two degenerate flavors of dynamical Wilson fermions and using dynamical sea staggered fermions with domain wall valence quarks. The two subdominant quadrupole…
Chiral quark models with non-local covariant separable interactions at finite temperature and chemical potential are investigated. We develop a formalism in which the different quark properties are evaluated taking into account the analytic…
A new model for the exchange of two gluons between the virtual photon and the proton, in non-diffractive deeply inelastic electron-proton scattering, is developed and studied. This model relies on a perturbative calculation, previously…
The inclusion of two-body exchange currents in the constituent quark model leads to several new relations between the electromagnetic form factors of the nucleon and Delta(1232). These are:(i) the neutron charge form factor can be expressed…
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…
Using non-local chiral quark model with simple pole ansatz for mass dependence on momentum and non-local currents satisfying Ward-Takahashi identities, we calculate pion to photon transition distribution amplitudes and relevant form…
We study the short-range nucleon-nucleon interaction in a nonrelativistic chiral constituent quark model by diagonalizing a Hamiltonian containing a linear confinement and a Goldstone boson exchange interaction between quarks. A finite…
The isospin I=0 and I=1 kaon-nucleon $S$, $P$, $D$, $F$ wave phase shifts are studied in the chiral SU(3) quark model by solving the resonating group method (RGM) equation. The calculated phase shifts for different partial waves are in…
We investigate the nucleon to Delta(1232) vector and axial vector amplitudes in the non-relativistic quark model of the Isgur-Karl variety. A particular interest is to investigate the SU(6) symmetry breaking, due to color hyperfine…
Calculations of the magnetic dipole, electric quadrupole and Coulomb quadrupole amplitudes for the transition $\gamma N\to \Delta$ are presented both in quenched QCD and with two flavours of degenerate dynamical quarks.
We review recent progress in the investigation of the electroexcitation of nucleon resonances, both in experiment and in theory. The most accurate results have been obtained for the electroexcitation amplitudes of the four lowest excited…
Within the chiral constituent quark model of Glozman and Riska, we discuss the stability of heavy pentaquarks, i.e. hadrons containing four light quarks and a heavy antiquark. The spin-dependent part of the Hamiltonian is dominated by the…
The electromagnetic transition form factors for the transition between the ground and excited states of nucleons are studied in the framework of the hard-wall model of AdS/QCD. The profile functions of the spinor and vector fields in the…
Quenched lattice QCD simulations and quenched chiral perturbation theory are used together for this study of strangeness in the nucleon. Dependences of the matrix elements on strange quark mass, valence quark mass and momentum transfer are…
We study the short-range nucleon-nucleon interaction in a nonrelativistic chiral constituent quark model by diagonalizing a Hamiltonian containing a linear confinement and a Goldstone boson exchange interaction between quarks. A finite…
A relativistic constituent quark model is applied to the gamma N -> N(1535) transition. The N(1535) wave function is determined by extending the covariant spectator quark model, previously developed for the nucleon, to the S11 resonance.…