Tree amplitudes at multiparticle threshold in a model with softly broken $O(2)$ symmetry

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

Tree amplitudes at multiparticle threshold in a model with softly broken $O(2)$ symmetry

Authors

Libanov, M. V.

Rubakov, V. A.

Troitsky, S. V.

Description

Tree amplitudes of the production of two kinds of scalar particles at threshold from one virtual particle are calculated in a model of two scalar fields with $O(2)$ symmetric quartic interaction and unequal masses. These amplitudes exhibit interesting factorial and exponential behaviour at large multiplicities. As a by-product we observe that the kinematically allowed decay of one real particle into $n$ real particles of another kind, all at rest, has zero tree amplitude in this model for $n>2$.
17 pages. Preprint INR-823/93