ELECTROWEAK ANOMALY AND LEPTON ASYMMETRY

It has recently been pointed out that shortly after the electroweak phase transition (t≃10−11 sec , T≃100–200 GeV ) there was a period of very effective baryon (and lepton) number violation driven by non-perturbative effects arising from the electroweak anomaly. Here we argue that as a result of these electroweak interactions the total asymmetry in leptons must be equal and opposite to the baryon asymmetry: L≡∑iLi=Le+Lμ+Lr=−B. Since the individual lepton numbers can be positive or negative, this does not preclude any large individual contribution, i.e., |Li|>B. This fact has important consequences for primordial nucleosynthesis if |Li|≳1.