  The well-known baryon and lepton numbers of the standard model of quarks and
leptons are extended to include new fermions and bosons in a simple structure
with several essential features. The usual heavy right-handed neutrino singlets
(for neutrino mass and leptogenesis) are related to the axion which solves the
strong CP problem. At the same time, baryon number is broken softly, allowing
the proton to decay. Associated with this breaking, a long-lived dark-matter
candidate (called the pseudo-sakharon) emerges. This new insight connects
proton decay to a new component of dark matter.
