Big bang nucleosynthesis with matter-antimatter domains

We investigate big bang nucleosynthesis (BBN) in a cosmic environment characterized by a distribution of small-scale matter-antimatter domains which are predicted in some electroweak baryogenesis scenarios. We find that antimatter domains spoil agreement between BBN abundance yields and observationally inferred primordial abundance limits which allows us to derive limits on their presence in the early universe. However, if only small amounts of antimatter are present, BBN with low deuterium and low He-4, as seemingly favored by current observational data, is possible. [S0031-9007(98)07413-4].