Varying leptonic chemical potentials and spatial variation of primordial deuterium at high z

We try to explain the spatial variation of primordial deuterium suggested by some observations by varying leptonic chemical potentials. The variation of the latter may take place in some scenarios of leptogenesis. The model predicts a large mass fraction of He-4 (35-60%) and Li-7 (up to 10(-9)) in deuterium-rich regions. Because of lepton family symmetry, the angular variations of cosmic microwave background radiation can be sufficiently small although still observable in future measurements. (C) 1999 Elsevier Science B.V. All rights reserved.