Some useful properties of a theory of variable mass particles

By a simple extension of the canonical formalism, one can include mass and proper time as dynamical variables in mechanics. Such a theory allows one to treat particles with variable mass and also classically decaying particles. The theory has other properties which offer a fresh approach to classical dynamics. For example, the inertia of a system becomes an active concept, and the rest mass of an interacting particle changes to include its binding energy. Also, the proper time as measured by a clock on a decaying particle runs at a different rate from a clock on a stable particle. This effect causes a ``decay red shift'' to be present in classically decaying systems, over and above other red shift effects. The effect could be used to remove the acausal properties of ``pre-acceleration'' in radiative reaction, and it is suggested that for rapidly decaying massive objects, like quasars, this effect might be responsible for part of their red shift.