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 $n \to \chi\chi\chi$ into non-relativistic can account for neutron anomaly, compatibly bounds from stars. be Dark Matter, and its cosmological abundance generated by freeze-in dominated at $T \sim m_n$. The associated processes \chi\chi\chi \gamma$, hydrogen ${\rm H}\to \chi\chi \chi\nu(\gamma)$ DM-induced disappearance $\bar\chi n \chi (\gamma)$ have rates below experimental of interest future experiments.