Radiative production of nonthermal dark matter

We compare dark matter production from the thermal bath in the early universe with its direct production through the decay of the inflaton. We show that even if dark matter does not possess a direct coupling with the inflaton, Standard Model loop processes may be sufficient to generate the correct relic abundance.

Figure 1

Parameter space in the plane ($\mathrm{\Lambda }$, $N{B}_R$) of points respecting PLANCK constraints, with the corresponding dark matter mass $m$ for the case with $n=6$. The lines correspond to the branching ratio determined in our microscopic approach for $y_{\chi }=0$ (white solid line) and $y_{\chi }={10}^{-4}{y}_f$ (white dashed line). See the text and Eq. (23) for details.

Figure 2

The radiative decay of the inflaton into a pair of dark matter fields.

Figure 3

The radiative decay of inflaton into a pair of gravitinos. Dashed (solid) lines in the loop represent the Higgs bosons (Higgsinos).

Figure 4

The total number density of gravitino. The top panel assumes the instantaneous thermalization, and the bottom panel takes into account the effect of noninstantaneous thermalization.