Strangeness production in antiproton annihilation on nuclei.

Abstract

The strangeness production in antiproton annihilation on nuclei is investigated by means of a cascade-type model, within the frame of the conventional picture of the annihilation on a single nucleon followed by subsequent rescattering proceeding in the hadronic phase. The following hadrons are introduced: N, \ensuremath{\Lambda}, \ensuremath{\Sigma}, \ensuremath{\Lambda}\ifmmode\bar\else\textasciimacron\fi{}, \ensuremath{\pi}, \ensuremath{\eta}, \ensuremath{\omega}, K, and K\ifmmode\bar\else\textasciimacron\fi{} and, as far as possible, the experimental reaction cross sections are used in our simulation. The numerical results are compared with experimental data up to 4 GeV/c. The \ensuremath{\Lambda}\ifmmode\bar\else\textasciimacron\fi{} yield is correctly reproduced, while the \ensuremath{\Lambda} and ${\mathit{K}}_{\mathit{s}}$ yields are overestimated in the p\ifmmode\bar\else\textasciimacron\fi{}Ta and p\ifmmode\bar\else\textasciimacron\fi{}Ne cases. On the other hand, the rapidity and perpendicular momentum distributions are well reproduced. It is shown that total strange yield is not very much affected by the associated production taking place during the rescattering process. It is also shown that the \ensuremath{\Lambda}/${\mathit{K}}_{\mathit{s}}$ ratio is largely due to the strangeness exchange reactions induced by antikaons. In particular, values of the order of 1 to 3 are expected in the energy range investigated here, independently of the detail of the hadronic phase dynamics. Finally, it is stressed that rapidity distributions are consistent with the rescattering process. Comparison with other works and implications of our results are examined.