Dark matter, the mysterious substance that makes up roughly a quarter of the Universe, may have its origin in pre-Big-Bang times, according to a new paper published in the Physical Review Letters.
This artist’s impression shows the evolution of the Universe beginning with the Big Bang on the left followed by the appearance of the Cosmic Microwave Background. The formation of the first stars ends the cosmic dark ages, followed by the formation of galaxies. Image credit: M. Weiss / Harvard-Smithsonian Center for Astrophysics.
“We revealed a new connection between particle physics and astronomy,” said study author Dr. Tommi Tenkanen, a postdoctoral researcher at the Johns Hopkins University.
“If dark matter consists of new particles that were born before the Big Bang, they affect the way galaxies are distributed in the sky in a unique way. This connection may be used to reveal their identity and make conclusions about the times before the Big Bang too.”
While not much is known about its origins, scientists have shown that dark matter plays a crucial role in the formation of galaxies and galaxy clusters.
For a long time, they believed that it must be a leftover substance from the Big Bang.
“If dark matter were truly a remnant of the Big Bang, then in many cases researchers should have seen a direct signal of dark matter in different particle physics experiments already,” Dr. Tenkanen said.
Using a new, simple mathematical framework, he shows that dark matter may have been produced during an epoch known as the cosmic inflation when space was expanding very rapidly.
The fast expansion is believed to lead to copious production of certain types of particles called scalars.
So far, only one scalar particle has been discovered, the famous Higgs boson.
“We do not know what dark matter is, but if it has anything to do with any scalar particles, it may be older than the Big Bang,” Dr. Tenkanen explained.
“With the proposed mathematical scenario, we don’t have to assume new types of interactions between visible and dark matter beyond gravity, which we already know is there.”
While the idea that dark matter existed before the Big Bang is not new, other theoretical physicists have not been able to come up with calculations that support the idea.
“This new study shows that researchers have always overlooked the simplest possible mathematical scenario for dark matter’s origins,” Dr. Tenkanen said.
“The study also suggests a way to test the origin of dark matter by observing the signatures dark matter leaves on the distribution of matter in the Universe.”
“While this type of dark matter is too elusive to be found in particle experiments, it can reveal its presence in astronomical observations.”
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Tommi Tenkanen. 2019. Dark Matter from Scalar Field Fluctuations. Phys. Rev. Lett 123 (6); doi: 10.1103/PhysRevLett.123.061302
