Collaborating for a "Perfect" Scan of Nuclear Matter
As the finishing touches are put on the world’s most powerful particle accelerator in Switzerland, and plans for others pop up across the globe, Brookhaven’s Relativistic Heavy Ion Collider (RHIC) continues to exploit its unique ability to explore the surprising features of matter bound by the strongest of Nature’s forces. Although RHIC’s overall mission is quite different from other machines on the horizon, new scientific facilities are incorporating heavy ion capabilities similar to RHIC. This healthy competition and collaboration with facilities worldwide will greatly enhance the exploration of nuclear matter — the inner cogs that make up the nucleus, and really, everything around us.
On the most basic level, scientists know that the nucleus is made of particles called protons and neutrons, which are made of smaller particles called quarks and gluons — the most fundamental constituents of matter. They know that the quarks are grouped into triplets held together by gluons (named for their Elmer’s-like properties). But, they also know that these elementary particles weren’t always glued together. Go back about 13.7 billion years, a hundred-millionth of a second after the Big Bang, and you’d find quarks and gluons floating freely. And that’s where it gets sticky.
Using RHIC, researchers have revealed surprising results in their quest to recreate this moment in history, in microcosm. By colliding beams of heavy gold nuclei at very high energies, RHIC provides a small-scale replication of the ultra-hot, dense conditions thought to have existed immediately following the birth of the universe. However, instead of producing a gas of free quarks and gluons, RHIC’s energetic collisions appear to produce something more like a liquid — a “perfect” liquid with almost no viscosity, or frictional resistance to flow.