Moduli portal dark matter

We show that moduli fields as mediators between the Standard Model and the dark sector can naturally lead to the observed relic abundance. Indeed, even if moduli are very massive, the nature of their couplings with matter and gauge fields allows to produce a sufficiently large amount of dark matter in the early Universe through the freeze-in mechanism. Moreover, the complex nature of the moduli fields whose real and imaginary parts couple differently to the thermal bath gives an interesting and unusual phenomenology compared to other freeze-in models of that type.