Antisymmetric tensor portals to dark matter

Both freeze-in of very weakly coupled dark matter and freeze-out of initially thermalized dark matter from the primordial heat bath provide interesting possibilities for dark matter creation in the early universe. Both scenarios allow for a calculation of baryon-dark matter coupling constants as a function of dark matter mass m χ , g = g ( m χ ) , due to the constraint that freeze-in or freeze-out produce the observed dark matter abundance. Here we compare the resulting coupling constants in the two scenarios if dark matter couples to baryons through an antisymmetric tensor portal. The freeze-in scenario predicts much smaller coupling in agreement with the nonthermalization postulate. We find that the couplings as a function of mass behave very differently in the two scenarios. • An antisymmetric tensor portal can account for the dark matter both through freeze-in or through freeze-out of dark matter. • The freeze-in scenario predicts much smaller coupling constants than thermal freeze-out. • Freeze-in also favors higher antisymmetric tensor masses and lower dark matter masses.