Dark Matter interpretation of the neutron decay anomaly

We add to the Standard Model a new fermion chi with minimal baryon number 1/3. Neutron decay n -> chi chi chi into non-relativistic chi can account for the neutron decay anomaly, compatibly with bounds from neutron stars. chi can be Dark Matter, and its cosmological abundance can be generated by freeze-in dominated at T similar to m(n) . The associated processes n -> chi chi chi gamma, hydrogen decay H -> chi chi chi nu(gamma) and DM-induced neutron disappearance (chi) over barn -> chi chi(gamma) have rates below experimental bounds and can be of interest for future experiments.

Automated summary

This study adds a new fermion chi to the Standard Model and explores its potential properties and applications in neutron decay and dark matter.