Antiproton-hydrogen atom annihilation. Final report, April-December 1985

Technical Report · Thu May 01 00:00:00 EDT 1986

OSTI ID:5413157

Morgan, D L

For antiproton energies of several eV or less, annihilation in matter occurs through atomic rearrangement processes in which the antiproton becomes bound to a nucleus prior to annihilation. Annihilation cross sections via rearrangement at such energies are much higher than for direct antiproton-nucleon annihilation and are, therefore, of consequence to antiproton annihilation propulsion of spacecraft. Existing calculations of the antiproton-hydrogen atom rearrangement cross section are semiclassical and employ the Born-Oppenheimer approximation. They also employ various arguments in regard to the behavior of the system when the Born-Oppenheimer approximation breaks down at small antiproton-proton separations. These arguments indicate that rearrangement is essentially irreversible. In this study, a detailed investigation was made of the antiproton-hydrogen atom system when the Born-Oppenheimer approximation breaks down. Results indicate that the previous arguments were approximately correct, but that there is a significant probability for rearrangement reversing prior to annihilation. This probability is estimated to be about 20%. This consequent reduction in annihilation cross section has little or no negative consequences for antiproton annihilation propulsion at the present time. However, because of the approximate nature of this result and because more-accurate values will be required in the future, it is important to conduct an accurate, fully quantum-mechanical calculation of antiproton-hydrogen atom rearrangement.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• OSTI ID: 5413157
• Report Number(s): AD-A-168262/4/XAB; UCID-20748
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTIPROTONS
ANNIHILATION
ATOMS
HYDROGEN
BORN-OPPENHEIMER APPROXIMATION
CROSS SECTIONS
NUCLEONS
PROPULSION SYSTEMS
RECOMBINATION
ANTIBARYONS
ANTIMATTER
ANTINUCLEI
ANTINUCLEONS
ANTIPARTICLES
BARYONS
BASIC INTERACTIONS
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
HADRONS
INTERACTIONS
NONMETALS
NUCLEI
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory
645203 - High Energy Physics- Particle Interactions & Properties-Theoretical- Weak Interactions & Properties