Scientists from the University of Oslo in Norway suggested a new mechanism of how dark matter is reproduced in the universe, rolling out a theory that its particles can interact with regular particles and transform them into dark matter, according to Physical Review Letters.
There are two models for dark matter production in the Universe. According to the so-called freeze-out models, a large initial quantity of dark matter is in equilibrium with the plasma of standard model particles in the early Universe, but then, as the Universe expands and cools, dark matter particles are being destroyed faster than they are created. The freeze-in models say that the Universe starts with little or no dark matter at all, and then standard model particles birth the dark matter ones.
Torsten Bringmann and his colleagues from the University of Oslo have come up with another model. According to the new theory, a small initial quantity of dark matter in the early Universe could interact with the standard model particles in a way that "contaminated" the particles and could transform them into dark matter.
The newly-transformed dark matter particles could then do the same thing to other standard model particles, allowing the dark matter to grow exponentially, with its spread being more rapid than in freeze-in models. Then, according to the hypothesis, this process would naturally slow down and stop as the Universe expanded, leading to the amount of dark matter that is observed today.
These findings could mean that there were consequences for the CMB’s power spectrum and other present-day properties of the Universe. However, in order for the potential mechanism to be supported or ruled out, more observations are needed, the researchers said.