SOLITONS IN A BABY-SKYRME MODEL WITH INVARIANCE UNDER AREA-PRESERVINGDIFFEOMORPHISMS

We study the properties of soliton solutions in an analogue of the Sky rme model in 2+1 dimensions whose Lagrangian contains the Skyrme term and the mass term, but no usual kinetic term. The model admits a symme try under area-preserving diffeomorphisms. We solve the dynamical equa tions of motion analytically for the case of spinning isolated baryon- type solitons. We take fully into account the induced deformation of t he spinning Skyrmions and the consequent modification of its moment of inertia to give an analytical example of related numerical behavior f ound by Piette, Schroers, and Zakrzewski. We solve the equations of mo tion also for the case of an infinite, open string, and a closed annul ar string. In each case, the solitons are of finite extent, so called ''compactons,'' being exactly the vacuum outside a compact region. We end with indications on the scattering of baby Skyrmions, as well as s ome considerations as the properties of solitons on a curved space.