Dark matter production through a non-thermal flavon portal

Understand

The Froggatt-Nielsen (FN) mechanism provides an attractive way of generating the determined fermion mass hierarchy and quark mixing matrix elements in the Standard Model (SM).

• Here we extend it by coupling the FN field, the flavon, to a dark sector containing one or more dark matter particles which are produced non-thermally sequentially through flavon production.
• Non-thermal flavon production occurs efficiently via freeze-in and through field oscillations.
• We explore this in the regime of high-scale breaking $\Lambda$ of the global $U(1)_{\textrm{FN}}$ group and at the reheating temperature $T_R\ll \Lambda$ where the flavon remains out of equilibrium at all times.