title: Geometric model for nuclear absorption from microscopic theory.
abstract: A parameter-free geometric model for nuclear absorption is derived from microscopic theory.  The expression for the absorption cross section in the eikonal approximation taken in integral form is separated into a geometric contribution, described by an energy-dependent effective radius, and two surface terms which are shown to cancel in an asymptotic series expansion.  For collisions of light nuclei, an expression for the effective radius is derived using  harmonic-oscillator nuclear density functions.  A direct extension to heavy nuclei with Woods-Saxon densities is made by identifying the equivalent half density radius for the harmonic-oscillator functions.  Coulomb corrections are incorporated and a simplified geometric form of the Bradt-Peters type obtained.  Results spanning the energy range of 1 MeV/nucleon to 1 GeV/nucleon are presented.  Good agreement with experimental results are obtained.
authors.affiliation: Vigyan Inc., Hampton, Virginia 23666, USA.
authors.forename: S
authors.initials: S
authors.lastname: John
authors.forename: L W
authors.initials: LW
authors.lastname: Townsend
authors.forename: J W
authors.initials: JW
authors.lastname: Wilson
authors.forename: R K
authors.initials: RK
authors.lastname: Tripathi
mesh_terms: D004601:Elementary Particles; D008433:Mathematics; D008962:Models, Theoretical; D009686:Nuclear Physics; D011522:Protons; D012542:Scattering, Radiation