Evidence for the decay of nuclear matter toroidal geometries in nucleus-nucleus collisions

Systematic experimental evidence is presented for the decay of nuclear matter from toroidal geometries using reactions of Kr-86 + Nb-93 at incident energies ranging from 35 to 95 MeV/nucleon. The decay of noncompact geometries is established through two charge-related observables, and the distinction between toroidal and bubblelike geometries is achieved through event shape analysis. Indications of these exotic geometries appear for beam energies between 60 and 75 MeV/nucleon.