Relativistic symmetries in the Hulthn scalar-vector-tensor interactions

In the presence of spin and pseudospin （p-spin） symmetries, the approximate analytical bound states of the Dirac equation for scalar-vector-tensor Hulth6n potentials are obtained with any arbitrary spin-orbit coupling number using the Pekeris approximation. The Hulth6n tensor interaction is studied instead of the commonly used Coulomb or linear terms. The generalized parametric Nikiforov-Uvarov （NU） method is used to obtain energy eigenvalues and corresponding wave functions in their closed forms. It is shown that tensor interaction removes degeneracy between spin and p-spin doublets. Some numerical results are also given.

Energy Levels of Spin-1/2 Particles with Yukawa Interaction

In this article, Yukawa interaction is used to study the relativistic spin-1/2 particles and obtain their energy levels. The role of Yukawa potential on the spin and pseudospin symmetry solution is investigated systematically by solving the Dirac equation with attractive scalar S(r) and repulsive vector V(r) potentials. Bound state spectrum and wave functions of Yukawa potential are obtained. It is found that the energy eigenvalues strongly depend on the potential parameters.

Electromagnetic Coupling of Negative Parity Nucleon Resonances N(1535) Based on Nonrelativistic Constituent Quark Model

The electromagnetic transition between the nucleon and excited baryons has long been recognized as an important source of information for understanding strong interactions in the domain of quark confinement. We study the electromagnetic properties of the excitation of the negative parity the N~*(1535) resonances in the nonrelativistic constituent quark model at large momentum transfers and have performed a calculation the longitudinal and transverse helicity amplitudes. Since the helicity amplitudes depend strongly on the quark wave function in this paper, we consider the baryon as a simple, non-relativistically three-body quark model and also consider a hypercentral potential scheme for the internal baryon structure, which makes three-body forces among three quarks. Since the hyper central potential depends only on the hyper radius, therefore, the Cornell potential which is a combination of the Coulombic-like term plus a linear confining term is considered as the potential for interaction between quarks. In our work, in solving the Schrodinger equation with the Cornell potential, the Nikiforov–Uvarov method employed, and the analytic eigen-energies and eigen-functions obtained. By using the obtained eigen-functions, the transition amplitudes calculated. We show that our results in the range Q^2> 2GeV^2 lead to an overall better agreement with the experimental data in comparison with the other three non-relativistic quark models.

A new non-microscopic study of cluster structures in light alpha-conjugate nuclei

In this paper, the alpha-cluster state in light alpha-conjugate nuclei is studied and a new suitable local potential model for the α-cluster phase of these nuclei is suggested. Using the generalized Nikiforov-Uvarov（NU）method, the clusterization energy for ^8Be,^12C,^16O and ^20Ne nuclei is calculated. Based on the obtained results, the clustering phenomenon is more probable at energies among excited levels and it happens neither at ground state nor at excited states of light alpha-conjugate nuclei. It is found that the presented formulation for clustering phenomenon reproduces the results of previous experimental and theoretical attempts for the mentioned nuclei. The consistency of the obtained results with the previous experimental and theoretical predictions indicates the reliability of this formulation for various types of alpha-conjugate nuclei.