“Isochronic” dynamical systems and nullification of amplitudes

Open Access funded by SCOAP3 - Sponsoring Consortium for Open Access Publishing in Particle PhysicsWe construct the set of theories which share the property that the tree-level threshold amplitudes nullify even if both initial and final states contain the same type of particles. The origin of this phenomenon lies in the fact that reduced classical dynamics describes the isochronic systems.Supported by the Łódź University grant No. 269. Supported by KBN grant No. 5 P03B 060 21