Nuclear annihilation by antinucleons

Abstract

We examine the momentum dependence of $bar p$$p$ and $bar n$$p$ annihilation cross sections by considering the transmission through a nuclear potential and the $bar p p$ Coulomb interaction. Compared to the $bar n p$ annihilation cross section, the $bar p p$ annihilation cross section is significantly enhanced by the Coulomb interaction for projectile momenta below $p_{rm lab} <$ 500 MeV/$c$, and the two annihilation cross sections approach the Pomeranchuk's equality limit [JETP {bb 30}, 423 (1956)] at $p_{rm lab}sim 500$ MeV/$c$. Using these elementary cross sections as the basic input data, the extended Glauber model is employed to evaluate the annihilation cross sections for $bar n$ and $bar p$ interaction with nuclei and the results compare well with experimental data.