Constraints on self-interacting Q-ball dark matter

We consider different types of Q-balls as self-interacting dark matter. For the Q-balls to act as the dark matter of the universe they should not evaporate, which requires them to carry very large charges; depending on the type, the minimum charge could be as high as Q similar to 10(33) or the Q-ball coupling to ordinary matter as small as similar to 10(-35). The cross-section-to-mass ratio needed for self-interacting dark matter implies a mass scale of in similar to 0(l) MeV for the quanta that the Q-balls consist of, which is very difficult to achieve in the MSSM. (C) 2002 Published by Elsevier Science B.V.