Dark Matter from Unstable B-balls

Abstract

The spectrum of MSSM admits solitons carrying baryonic charge, or B-balls. In an inflationary universe they can be produced in significant numbers by a break-up of a scalar condensate along the flat directions. It is shown that if SUSY breaking is mediated to the observable sector by gravity, B-balls are unstable but decay to baryons and LSPs typically well below the electroweak phase transition. It is argued that B-balls could be the source of most baryons and cold dark matter in the universe, with their number densities related by $n_{LSP}\simeq 3n_B$. For B-balls to survive thermalization, the reheating temperature after inflation should be less than about $10^3$ GeV.

Comments: 11 pages, 3 ps figures. Invited talk at DARK98 conference, Heidelberg, Germany, July 20-25