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We present a parametrization and two fits to proton nucleus scattering data from 20 to 1040 MeV and mass ranges from $^{4}\mathrm{He}$ to $^{208}\mathrm{Pb}$. We show that $^{4}\mathrm{He}$ can be included with the other nuclei instead of having to be treated separately as previously [B. C. Clark, E. D. Cooper, and S. Hama, Phys. Rev. C 73, 024608 (2006)]. An interesting change of sign in the imaginary potentials at low energies and high densities is noted. This may be an indicator of density dependence in the relativistic $g$ matrix.

Comparisons are made between results of calculations for intermediate energy nucleon-nucleus scattering for 12C, 16O, 40Ca, 90Zr, and 208Pb, using optical potentials obtained from global Dirac phenomenology and from a microscopic Schr\"odinger model. Differential cross sections and spin observables for scattering from the set of five nuclei at 65 MeV and 200 MeV have been studied to assess the relative merits of each approach. Total reaction cross sections from proton-nucleus and total cross sections from neutron-nucleus scattering have been evaluated and compared with data for those five targets in the energy range 20 MeV to 800 MeV. The methods of analyses give results that compare well with experimental data in those energy regimes for which the procedures are suited., Comment: 22 pages, 12 figures

A new way of dealing with the unwanted high momentum components in low energy pion-nucleus optical potentials is presented. The method is developed strictly in accordance with a principle of “smoothness” which has been found very helpful in other contexts of nuclear physics. The effect of taking a standard optical potential and “smoothing” it is small for the pion elastic scattering cross section but large for the pion wavefunction in the nuclear interior. This has the dramatic and much needed effect of lowering the (p,π) differential cross section by an order of magnitude because this reaction is sensitive to the high momentum components of the wavefunction.

The amplitude for the ( p,..pi../sup +/) reaction is calculated in a relativistic one-nucleon model with use of a distorted-wave Born-approximation approach. The nucleon continuum and bound-state wave functions are solutions of Dirac equations with appropriate vector and scalar nuclear potentials. Calculations with the pseudovector ..pi..NN coupling, which satisfies the constraints of partial conservation of the axial-vector current, are in much better agreement with the data than calculations with the simple pseudoscalar coupling.

We present a global relativistic optical model for p+40Ca consisting of Lorentz scalar and vector potentials parametrized as a function of energy. The shapes chosen are Woods-Saxons for the real potentials, and a linear combination of Woods-Saxons and derivative Woods-Saxons for the imaginary potentials.

The diffusivity of the nuclear surface plays an important role in peripherial collisions between two heavy ions. We show that a finite range force produces a diffuse surface for static nuclei in the Vlasov prescription. The surface is calculated self-consistently. This will allow us to perform more realistic calculations for peripheral reactions in the Boltzmann-Uehling-Uhlenbeck model.

The sensitivities to input parameters of the (p,${\ensuremath{\pi}}^{+}$) observables calculated using a relativistic one-nucleon distorted-wave Born approximation model are discussed. We investigate the effects of variations in bound state geometry and of ambiguities in the pion optical potential, as well as finite range effects in the production vertex.

We present the first global relativistic optical-model treatment of proton-nucleus elastic scattering. Energy-dependent optical potential parameters for the Lorentz vector and scalar potentials of Dirac phenomenology are given. Several different assumptions regarding the optical-model energy dependence are considered. Constraints from relativistic mean-field theory are presented.

There is increasing evidence that relativistic effects play an important role in the description of nuclear structure and reactions. The development of a relativistic impulse approximation (RIA) and its success at intermediate energies is a case in point. Although the RIA cannot be used to describe proton scattering at low energies it successfully describes recent p–12C data at 46.8 MeV. We discuss a phenomenological nuclear optical model approach based on the Dirac equation containing large cancelling Lorentz scalar and Lorentz vector potentials. The model is used to describe proton and neutron scattering at low energy (T