Collider Reveals New Clues about the Origins of the Universe: Change from 'Quark Soup' to Atoms

The early universe is a difficult subject to study. Yet scientists may have just uncovered new clues about its origins. Researchers have observed a phase transition different from the smooth transition of the early universe from the hot "soup" of subatomic particles to atoms, made up of neutrons, protons and electrons that are the building blocks of matter.

The researchers were actually looking at phase transitions, which occur when matter changes states. For example, a familiar phase transition is when water is heated to boiling. The water's temperature rises until it begins to turn into steam. The temperature stops rising as the heat's energy goes into the change of state from liquid to gas.

In this particular case, the scientists were looking for the signature of the moment when energy going into the system stops producing one effect and instead goes into producing the phase change instead. More specifically, they were examining the sharp phase transition between the quantum plasma of the early universe and the normal matter of atoms and molecules.

"We can't go back in time, but we can reproduce the conditions present just after the Big Bang and try to understand the evolution of the early universe," said Yadav Pandit, one of the researchers, in a news release.

The researchers analyzed data on heavy gold nuclei collisions at various energies within huge particle detectors at Brookhaven. They ended up finding the signature, which was a temporary disappearance of a particular kind of particle flow observed coming out of the collisions.

"When the collision takes place at an energy close to a first-order phase transition, the expansion and the resulting deflection of the emitted particles is 'softened,'" said Pandit in a news release. "Energy that would normally expand the system is instead going into changing the state of matter-melting the hadrons to free the quarks and the gluons."

The findings take physicists one step closer to understanding the complete phase structure of nuclear matter.  This, in turn, could allow scientists to understand a bit more about the origins of our early universe.

The findings are published in the journal Physical Review D.