Q-ball collisions in the MSSM: gravity-mediated supersymmetry breaking

Collisions of non-topological solitons, Q-balls, are studied in a typical p otential in the Minimal Supersymmetric Standard Model where supersymmetry h as been broken by a gravitationally coupled hidden sector. Q-ball collision s are studied numerically on a two dimensional lattice for a range of Q-bal l charges. Total cross-sections, as well as cross-sections for fusion and c harge-exchange are calculated. The average percentage increase in charge ca rried by the largest Q-ball after a collision is found to be weakly depende nt on Uhe initial charge. (C) 2000 Elsevier Science B.V. All rights reserve d.