Breakthrough in research on mysterious 'dark matter'

A new model has been proposed for the mysterious 'dark matter,' which as per the scientists makes 80 percent of the substance of our universe.

Mikhail Medvedev, professor at the University of Kansas, said that dark matter was some unknown matter, most likely a new elementary particle or particles beyond the Standard Model. It had never been observed directly, but revealed itself via gravity it produced in the universe.

Medvedev's theory rests on the behavior of elementary particles that had been observed or hypothesized. According to today's prevalent Standard Model theory of particle physics, elementary particles, categorized as varieties of quarks, leptons and gauge bosons, are the building blocks of an atom. The properties, or "flavors," of quarks and leptons are prone to change back and forth, because they can combine with each other in a phenomenon called flavor-mixing.

He compared flavor-mixing to white light that contains several colors and can generate a rainbow, explaining that if white was a particular flavor, then red, green and blue would be different masses that mixed up together to create white. By changing proportions of red, green and blue in the mix, one could make different colors, or flavors, other than white.

Medvedev said that dark matter might interact with normal matter extremely weakly, which was why it hadn't been revealed already in numerous ongoing direct detection experiments around the world. So physicists devised a working model of completely collisionless (noninteracting), cold (that is, having very low thermal velocities) dark matter with a cosmological constant (the perplexing energy density found in the void of outer space), which they term the "Lambda-CDM model."

The results demonstrated that the flavor-mixed, two-component dark matter model resolved all the most pressing Lambda-CDM problems simultaneously, said the KU researcher.

The study is published in Physical Review Letters.