# Accession Number:

## AD0702406

# Title:

## ON ANNIHILATION AND OTHER INTERACTIONS OF POSITRONS IN A PLASMA.

# Descriptive Note:

## Final technical rept. (Part 2),

# Corporate Author:

## FLORIDA UNIV GAINESVILLE DEPT OF NUCLEAR ENGINEERING SCIENCES

# Personal Author(s):

# Report Date:

## 1970-01-01

# Pagination or Media Count:

## 140.0

# Abstract:

A consistent derivation of the nonrelativistic Hamiltonian for a many-body electron-positron system is given as well as a general formula for the annihilation probability in such a system. The derivations begin with the proper relativistic expressions and are based on a power expansion of the electron-positron field operators in terms of kK, where hk is the nonrelativistic momentum of the particles and K the inverse of the electron Compton wavelength. The theory is carried out up to the second power in kK for the Hamiltonian as well as the annihilation probability. An upper momentum cut-off kmax K is introduced to avoid divergences and insure the convergence of the expansion. The annihilation rate and the angular correlation function are then evaluated for a plasma as a function of the electron temperature, assuming thermal equilibrium for electrons as well as positrons. Finally, a short survey of other processes than annihilation with free electrons is given. author

# Descriptors:

# Subject Categories:

- Nuclear Physics and Elementary Particle Physics
- Plasma Physics and Magnetohydrodynamics