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∼1033 or the Q-ball coupling to ordinary matter as small as ∼10−35. The cross-section-to-mass ratio needed for self-interacting dark matter implies a mass scale of m∼O(1) MeV for the quanta that the Q-balls consist of, which is very difficult to achieve in the MSSM.