By Peter Weiss
An elusive primordial soup of particles may have simmered last year in the Relativistic Heavy Ion Collider, or RHIC, a new particle accelerator at Brookhaven National Laboratory in Upton, N.Y.
The soup would have been a quark-gluon plasma—an astoundingly hot fluid brimming with quarks and gluons, the building blocks of protons and neutrons. In its attempts to make the plasma, RHIC revs gold nuclei to nearly light speed and slams them together (SN: 8/26/00, p. 136). The particle collisions have yielded the densest, hottest matter ever observed in a lab.