Late-decaying Q-ball with BBN lifetime

In the Affleck-Dine mechanism of baryogenesis, non-topological solitons called Q-balls can be formed. In this work we propose that such Q-balls decay during the BBN era and study the cosmological consequence of such late decays. We find that the late-decaying baryonic Q-balls with lifetime of about 10s can provide a new developing mechanism for the BBN through a rolling baryonto-photon ratio η, which can naturally explain the discrepancy of the BBN prediction with the WMAP data on Li abundance. For the late-decaying leptonic Q-balls with lifetime of about 10s, we find that their decay product, gravitinos, can serve as a dark matter candidate and give an explanation for the approximate equality of dark and baryon matter densities. 96.35.+d, 04.65.+e, 12.60.Jv Typeset using REVTEX