Thermodynamics of non-topological solitons Original Research Article

In theories with low energy supersymmetry breaking, the effective potential for squarks and sleptons has generically nearly flat directions, V(φ) ∼ M4(log(φ/M))n This guarantees the existence of stable non-topological solitons, Q-balls, that carry large baryon number, B ≳ (M/mp)4, where mp is the proton mass. We study the beaaviour of these objects in a high temperature plasma. We show that in an infinitely extended system with a finite density of the baryon charge, the equilibrium state is not homogeneous and contains Q-balls at any temperature. In a system with a finite volume, Q-balls evaporate at a volume-dependent temperature. In the cosmological context, we formulate the conditions under which Q-balls, produced in the early Universe, survive till the present time. Finally, we estimate the baryon to cold dark matter ratio in a cosmological scenario in which Q-balls are responsible for both the net baryon number of the Universe and its dark matter. We find out naturally the correct orders of magnitude for M ∼ 1-10 TeV: η 10−10(M/TeV)−2(B/1026)−12.