Non-topological kink scattering in a two-component scalar field theory model

Abstract

In this paper the scattering between the non-topological kinks arising in a family of two-component scalar field theory models is analyzed. A winding charge is carried by these defects. As a consequence, two different classes of kink scattering processes emerge: (1) collisions between kinks that carry the same winding number and (2) scattering events between kinks with opposite winding number. The variety of scattering channels is very rich and it strongly depends on the collision velocity and the model parameter. For the first type of events, four distinct scattering channels are found: kink reflection (kinks collide and bounce back), one-kink (partial) annihilation (the two non-topological kinks collide causing the annihilation of one half of each kink and the subsequent recombination of the other two halves, giving rise to a new non-topological kink with the opposite winding charge), winding flip kink reflection (kinks collide and emerge with the opposite winding charge) and total kink annihilation (kinks collide and decay to the vacuum configuration). For the second type of events, the scattering channels comprise bion formation (kink and antikink form a long-living bound state), kink-antikink passage (kinks collide and pass each other) and kink-antikink annihilation (kink and antikink collide and decay to the vacuum configuration).