Zeros of tree amplitudes at rest and symmetries of mechanical systems

Libanov, M. V.; Rubakov, V. A.; Troitsky, S. V.

Zeros of tree amplitudes at rest and symmetries of mechanical systems

Authors

Libanov, M. V.

Rubakov, V. A.

Troitsky, S. V.

Description

We consider the tree amplitudes of production of $n_2$ scalar particles by $n_1$ particles of another kind, where both initial and final particles are at rest and on mass shell, in a model of two scalar fields with $O(2)$ symmetric interaction and unequal masses. We find that these amplitudes are zero except for the lowest possible $n_1$ and $n_2$, and that the cancellation of the corresponding Feynman graphs occurs due to a special symmetry of the classical mechanical counterpart of this theory. This feature is rather general and is inherent in various other scalar field theories.
11 pages Preprint INR-830/93, August 1993