Browsing by Subject "SCALAR-FIELD"

Sort by: Order: Results:

Now showing items 1-2 of 2
  • Fairbairn, Malcolm; Kainulainen, Kimmo; Markkanen, Tommi; Nurmi, Sami (2019)
    We demonstrate the existence of a generic, efficient and purely gravitational channel producing a significant abundance of dark relics during reheating after the end of inflation. The mechanism is present for any inert scalar with the non-minimal curvature coupling xi RX2 and the relic production is efficient for modest values xi= O(1). The observed dark matter abundance can be reached for a broad range of relic masses extending from m similar to 1keV to m similar to 10(8) GeV, depending on the scale of inflation and the dark sector couplings. Frustratingly, such relics escape direct, indirect and collider searches since no non-gravitational couplings to visible matter are needed.
  • Bernal, Nicolas; Rubio, Javier; Veermäe, Hardi (2020)
    In the Starobinsky model of inflation, the observed dark matter abundance can be produced from the direct decay of the inflaton field only in a very narrow spectrum of closeto-conformal scalar fields and spinors of mass similar to 10(7) GeV. This spectrum can be, however, significantly broadened in the presence of effective non-renormalizable interactions between the dark and the visible sectors. In particular, we show that UV freeze-in can efficiently generate the right dark matter abundance for a large range of masses spanning from the keV to the PeV scale and arbitrary spin, without significantly altering the heating dynamics. We also consider the contribution of effective interactions to the inflaton decay into dark matter.