Particle Collider Experiment Recreates the Big Bang's Primordial Soup - and Finds Unexpected Pattern
SUMMARYPhysicists at Brookhaven National Laboratory’s STAR experiment at the Relativistic Heavy Ion Collider analyzed about 1 billion gold-ion collisions and found an unexpected dip in how strongly charged particles were flung sideways. The pattern may point to a long-sought critical point in nuclear matter, offering a new way to study how the early universe’s quark-gluon plasma cooled into protons and neutrons. The findings were published September 22 in Physical Review Letters.
"Physicists smashed gold nuclei together at nearly the speed of light and found an unexpected pattern in the particles..." writes Live Science.
"If confirmed, that pattern could help reveal how the hot soup of quarks and gluons that filled the universe in the first few microseconds after the Big Bang cooled and condensed into the protons and neutrons that make up ordinary matter today."
In every collision, particles are flung out sideways; how hard they are flung, on average, varies slightly from one collision to the next. Physicists expected the size of these variations to change smoothly as they adjusted the collision energy. Instead, the variations dipped, shrinking and then growing again. This dip could be a sign of a long-sought "critical point," a special set of conditions at which nuclear matter changes the way it transforms from one form to another.
The signal, detected by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in New York, is strong enough that it is very unlikely to be a statistical accident. However, the researchers cautioned that the dip is a tantalizing hint, not proof of the long-sought transition. They published their findings Sept. 22 in the journal Physical Review Letters...
The team analyzed roughly 1 billion collisions, measuring how hard charged particles were flung sideways out of the fireball, according to the article.
The dip "does point to a set of conditions where the behavior of nuclear matter changes, and it gives theorists a new, precise measurement to test their calculations against," study co-author Rutik Manikandhan, told Live Science.