We investigate what would be the consequences for leptogenesis of the
existence of a charged SU(2)_L singlet scalar delta^+. If such a scalar
particle exists, it allows the right-handed neutrinos to couple not only to
left-handed lepton and Higgs doublets as in ordinary leptogenesis, but also to
a right-handed charged lepton and a delta^+. This provides a new source of
leptogenesis which can be successful in a non-resonant way at scales as low as
TeV. The incorporation of this scenario in left-right symmetric and unified
models is discussed.Comment: To appear in the proceedings of 41st Rencontres de Moriond on
Electroweak Interactions and Unified Theories, La Thuile, Aosta Valley,
Italy, 11-18 Mar 200
