LOZANO LEYVA , Manuel Luis

Entre las dificultades que presenta el análisis de la reacción núcleo - núcleo, dentro de la aproximación anterior, posiblemente la mayor sea el tipo de potencial que entra en juego. Una de las mejores vías para conocer dicho potencial es el estudio de la dispersión elástica. Las características generales de la dispersión elástica de núcleos...

With a simple parametrization of the empirical imaginary potential depths, the real potential induced by a dispersion relation is calculated analytically for the elastic scattering of O16 by several target nuclei. Between 25e50 % of the real potential empirical depths can be attributed to this dispersive contribution when the energy approaches...

We study the effect of the elastic transfer process on sub-barrier fusion reactions between similar nuclei. The coupling to the elastic transfer channel is described in terms of a parity dependent potential, directly obtained from the transfer form factor. Within the simple barrier penetration model, we find that this effect can account for a...

The energy dependence of the fusion cross section and its maximum value are well predicted, for a wide range of nuclei and energies, by introducing information on the nuclear matter density distribution into a simple formula

The neutron capture cross section of 204Pb has been measured at the CERN n TOF installation with high resolution in the energy range from 1 eV to 440 keV. An R-matrix analysis of the resolved resonance region, between 1 eV and 100 keV, was carried out using the SAMMY code. In the interval between 100 keV and 440 keV we report...

The depth of the imaginary part of the optical potential is derived from the assumption that, at a given energy and for each partial wave L, it is proportional to the compound nucleus density level up to a given excitation energy above the yrast level corresponding to the angular momentum L, and remains a constant for smaller values of L. The...

The direct transfer of four nucleons in reactions with superfluid systems is compared with the feeding of the same final channel by a successive transfer of correlated nucleon pairs. A quantitative analysis is carried out for the reaction 120Sn+112Sn which shows the overwhelming dominance of the direct multiparticle transfer at bombarding...

Qualitative arguments are used to estiamte the ratio of excitation energies between heavy and light fragments for asymmetric heavy-ion collisions. The value of this quantity is linked to the relative role played by inelastic and transfer degrees of freedom and thereby to an approximate function of the total kinetic energy loss. A numerical...

We study the high energy behaviour of fermions hitting a general wall caused by a first-order phase transition. The wall profile is introduced through a general analytic function. The reflection coefficient is computed in the high energy limit and expressed in terms of the poles of the wall profile function. It is shown that the leading...

Analytical solutions of dispersion relations in the nucleon-nucleus optical model have been found for both volume and surface potentials. For the energy dependence a standard Brown-Rho function has been assumed for both the volume and surface imaginary contributions multiplied in this later case by a decreasing exponential...

A spherical optical model potential (OMP) containing a dispersive term is used to fit the available experimental database of s(u) and sT for n127Al covering the energy range 0.1–250 MeV using relativistickinematics and a relativistic extension of the Schrödinger equation. A dispersive OMP with parameters that show a smooth...

The critical radii obtained from analyses of the elastic scattering of alpha-particles by a range of nuclei are found to be closely connected with the nuclear matter distributions obtained by summing the squares of single-particle wavefunctions. This provides a method of calculating the details of the optical potentials from the structure of...

We exploit analytic properties of the optical potential for elastic scattering of α particles on nuclei to extract information on the effective interaction that should be used to describe the motion of a cluster of two neutrons and two protons bound to a nuclear system. This prescription solves long-standing ambiguities in the formalisms used...

A characteristic pattern frequently observed in the angular distribution of heavy-ion elastic scattering at moderate energies above the Coulomb barrier has been attributed either to a Fresnel diffraction or to a rainbow effect. We propose a comparison between the strong absorption radius Rsa and the rainbow radius Rr at different energies,...

The energy dependence of both the strong absorption radius, Rsa, and the rainbow distance, Rr, in the elastic scattering of a dozen pairs of heavy ions is studied. Rsa decreases with energy linearly in E−13 while Rr increases linearly in E−32. The rainbow effect appears to prevail (Rr > Rsa) above a certain energy which is proportional to the...