  We propose a mechanism for baryogenesis from particle decays or annihilations
that can work at the TeV scale. Some heavy particles annihilate or decay into a
heavy sterile neutrino N (with M > 0.5 TeV) and a "light" one \nu (with m <<
100 GeV), generating an asymmetry among the two helicity degrees of freedom of
\nu. This asymmetry is partially transferred to Standard Model leptons via fast
Yukawa interactions and reprocessed into a baryon asymmetry by the electroweak
sphalerons. We illustrate this mechanism in a WIMPy baryogenesis model where
the helicity asymmetry is generated in the annihilation of dark matter. This
model connects the baryon asymmetry, dark matter, and neutrino masses. Moreover
it also complements previous studies on general requirements for baryogenesis
from dark matter annihilation. Finally we discuss other possible realizations
of this helicitogenesis mechanism.
