Chiral gauge theories and a Dirac neutrino - Dark Matter connection

It is proposed that all light fermionic degrees of freedom, including the Standard Model (SM) fermions and all possible light beyond-the-standard model fields, are chiral with respect to some spontaneously broken abelian gauge symmetry. A new gauge symmetry U(1)(v) is required if light fermionic new states are to exist. Anomaly cancellations mandate the existence of several new fields with nontrivial U(1)(v) charges. A general technique to write down chiral-fermions-only models that are at least anomaly-free under a U(1) gauge symmetry is described. A concrete example that provides a Dark Matter candidate and leads to parametrically small Dirac neutrino masses is further developed.