Theory of positron production in heavy-ion collisions
- 1 July 1981
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review A
- Vol. 24 (1), 103-128
- https://doi.org/10.1103/physreva.24.103
Abstract
Collisions of very heavy ions at energies close to the Coulomb barrier are discussed as a unique tool to study the behavior of the electron-positron field in the presence of strong external electromagnetic fields. To calculate the excitation processes induced by the collision dynamics, a semiclassical model is employed and adapted to describe the field-theoretical many-particle system. An expansion in the adiabatic molecular basis is chosen. Energies and matrix elements are calculated using the monopole approximation. In a supercritical () quasiatomic system the level joins the antiparticle continuum and becomes a resonance, rendering the neutral vacuum state unstable. Several methods of treating the corresponding time-dependent problem are discussed. A projection-operator technique is introduced for a fully dynamical treatment of the resonance. Positron excitation rates in and states are obtained by numerical solution of the coupled-channel equations and are compared with results from first- plus second-order perturbation theory. Calculations are performed for subcritical and supercritical collisions of Pb-Pb, Pb-U, U-U, and U-Cf. Strong relativistic deformations of the wave functions and the growing contributions from inner-shell bound states lead to a very steep dependence of positron production. The results are compared with available data from experiments done at GSI. Correlations between electrons and positrons are briefly discussed.
Keywords
This publication has 90 references indexed in Scilit:
- Fermions and bosons interacting with arbitrarily strong external fieldsPhysics Reports, 1978
- Quantum electrodynamics of strong fieldsReports on Progress in Physics, 1977
- Positron Creation in Superheavy Quasi-MoleculesAnnual Review of Nuclear Science, 1976
- Auto-ionization of positrons in heavy ion collisionsThe European Physical Journal A, 1972
- Solution of the Dirac Equation for Strong External FieldsPhysical Review Letters, 1972
- Electron shells in over-critical external fieldsThe European Physical Journal A, 1972
- Interior electron shells in superheavy nucleiThe European Physical Journal A, 1969
- On Gauge Invariance and Vacuum PolarizationPhysical Review B, 1951
- Materieerzeugung im anschaulichen und im gequantelten Wellenbild der MaterieThe European Physical Journal A, 1941
- Die Reflexion von Elektronen an einem Potentialsprung nach der relativistischen Dynamik von DiracThe European Physical Journal A, 1929