e^± Ar scattering in the energy range 1 eV ≤ E_i ≤ 0.5 GeV

A theoretical investigation on differential, integral, momentum transfer, viscosity cross sections and spin polarization for elastically scattered electrons and positrons from Ar atoms in the energy range 1 eV ≤ E _i ≤ 0.5 GeV is presented. In addition, we have studied the critical minima in the elastic differential cross sections, and the absorption, total and ionization cross sections. Two different theoretical approaches, depending upon the incident energy, are employed for solving the relativistic Dirac equation with the partial-wave decomposition. The solution of the relativistic equation involves the use of either complex optical-model potentials or only nuclear potentials at higher energies. A comparison of the present results with the available experimental data and other theoretical findings produces a reasonable agreement throughout the investigated energy range. (paper)