We bring together the physics of preheating, following a period of inflation, and the dynamics of non-topological solitons, namely oscillons. We show that the oscillating condensate that makes up an oscillon can be an efficient engine for producing heavy fermions, just as a homogeneous condensate is known for doing the same. This then allows heavy fermions to be produced when the energy scale of the Universe has dropped below the scale naturally associated to the fermions.
Saffin, P. M. (in press). Recrudescence of massive fermion production by oscillons. Journal of High Energy Physics, 2017(7), Article 126. https://doi.org/10.1007/JHEP07%282017%29126