%\subsection{The scattering term \editor{Johannes Peter}}
The basis of the description of the reactive part of the scattering amplitude 
are two particle binary collisions (hence binary cascade), 
resonance production, and decay. Based on the cross-section described later
in this paper, collisions will occur when the transverse distance $d_t$ 
of any projectile target pair becomes smaller than the black disk radium
corresponding to the total cross-section $\sigma_t$
$${\sigma_t\over \pi} > d_t^2$$
In case of a collision, all particles will be propagated to the estimated
time of the collision, i.e. the time of closest approach, and the collision
final state is produced.


% General description of the scattering term.

% We do discrete binary reactions, and decays. Hence the name binary cascade.

% We do two particle reactions

% in this we assume the breit frame.

% We differencate: Nucleon nucleon scattering
% pion nucleon scattering
% elastic
% resoance production (t-channel)
% resonance excitation (s-channel)
% decay

% the scattering cross-sections are based on the following channel cross-sections.
% Parametrizations similar to UrQMD parametrizations. Comparisons with HERA data
% to show the quality. The total cross-sections for pp scattering, and the same as
% sum of all the channel cross-sections.

% The resonances taken into account for production are the following:
% Delta, N-star.

% Kaons will not further react.
% Resonances will not undergo secondary scatters, but only decay.
