467Theory of Special Relativity
13.11 RELATIVISTIC KINEMATICS OF COLLISIONS
The subject of collisions is of considerable interest in experimental high-energy physics. Although
the interactions (forces) between elementary particles are non-classical, as long as the particles
involved in a reaction are outside the region of mutual interaction, their mean motion can be
described by classical mechanics. The fundamental principles involved in the analysis of collisions
are the conservation laws of momentum and energy. Because energy and momentum form a four-
momentum vector, the conservation equations can be written as one four-vector equation. We shall
see that it is easy to work with this four-vector equation.
We shall restrict our discussion to ...