PRIMORDIAL MAGNETIC-FIELDS, RIGHT ELECTRONS, AND THE ABELIAN ANOMALY

In the standard model there are charges with Abelian anomaly only (e.g ., right-handed electron number) which are effectively conserved in th e early Universe until some time shortly before the electroweak scale. A state at finite chemical potential of such a charge, possibly arisi ng due to asymmetries produced at the grand unified theory scale, is u nstable to the generation of hypercharge magnetic field. Quite large m agnetic fields (similar to 10(22) G at T similar to 100 GeV with typic al inhomogeneity scale similar to 10(6)/T) can be generated. These fie lds may be of cosmological interest, potentially acting as seeds for a mplification to larger scale magnetic fields through nonlinear mechani sms. Previously derived bounds on exotic B - L violating operators may also be evaded.