This is a short presentation of the results for the pion-nucleon distribution amplitudes which are expressed in terms of the nucleon distribution amplitudes with the help of current algebra. Everything is considered to be at threshold.
We consider the two-flavor version of the extended linear sigma model (eLSM), which contains (pseudo)scalar and (axial-)vector quark-antiquark mesons, a scalar glueball (predominantly corresponding to $f_{0}(1710)$), as well as the nucleon and its chiral partner. We extend this model by the additional light scalar meson $f_{0}(500)$, predominantly a putative four-quark state. We investigate various interaction terms of the four-quark and glueball states with the other particles, some of which preserve and some of which explicitly break the $U(1)_{\textrm{A}}$ symmetry. We test our model by per…
This work represents an extension of the single pion production model proposed by D. Rein. The model consists of resonant pion production and nonresonant background contributions coming from three Born diagrams in the helicity basis. The new work includes lepton mass effects, and nonresonant interaction is described by five diagrams based on a nonlinear σ model. This work provides a full kinematic description of single pion production in the neutrino-nucleon interactions, including resonant and nonresonant interactions in the helicity basis, in order to study the interference effect.
The simple model describing charge independence and charge symmetry breaking of the pion-nucleon coupling constant is proposed. The model, which has simple physical meaning and foundation, suggests directly proportional dependence of the pion-nucleon coupling constants on the masses of interacting nucleons and pions. Charge dependence of the pion-nucleon coupling constant and the $^{1}S_{0}$-state low-energy nucleon-nucleon ($NN$) scattering parameters are studied on the basis of the Yukawa meson theory. The values of the $np$ and $nn$ interaction characteristics calculated by the proposed mod…
We study relationship between the physical quantities that characterize pion-nucleon and nucleon-nucleon interaction on the basis of the fact that nuclear forces in the nucleon-nucleon system at low energies are mainly determined by the one-pion exchange mechanism. By making use of the recommended proton-proton low-energy scattering parameters, we obtain the following value for the charged pion-nucleon coupling constant g$_{π^{\pm }}^{2}/4π=14.55(13)$. Calculated value of this quantity is in excellent agreement with the experimental result g$_{π^{\pm }}^{2}/4π=14.52(26)$ of the Uppsala Neutron…
Taking into account PDFs obtained by various Collaborations, the momentum transfer dependence of GPDs of the pion are obtained. The calculated electromagnetic and gravitomagnetic form factors of the pions and nucleons are used for the description of the pion-nucleon elastic scattering in a wide energy and momentum transfer region with minimum fitting parameters.
The Nucleon-Nucleon interaction in the singlet ($^1 S_0$) and triplet ($^3 S_1$) channels have been studied in the framework of Relativistic Harmonic Model using the Resonating Group Method in Born-Oppenheimer approximation. The full Hamiltonian consists of the kinetic energy, two body confinement potential, confined one gluon exchange potential and one pion exchange potential. Contribution of Confined One Gluon Exchange Potential and One Pion Exchange Potential to the adiabatic nucleon-nucleon interaction potential is discussed.
Owing to the Kubo relation, the shear viscosities of pionic and nucleonic components have been evaluated from their corresponding retarded correlators of viscous stress tensor in the static limit, which become non-divergent only for the non-zero thermal widths of the constituent particles. In the real-time thermal field theory, the pion and nucleon thermal widths have respectively been obtained from the pion self-energy for different meson, baryon loops and the nucleon self-energy for different pion-baryon loops. We have found a non-monotonic momentum distributions of pion and nucleon thermal …
The effect of the non-perturbative term is investigated for the pion-nucleon scattering. Including the self-energy of nucleon the cross section of the elastic scattering results in a constant value at the laboratory momentum $p_L \to \infty$. The amplitude of the forward direction is applied to the dispersion relation.