Fireballs of Free Quarks; April 2000; Scientific American Magazine; by Collins, Reichert; 2 Page(s)

Not every scientific discovery is heralded by a clear cry of "Eureka!" A case in point is the study of an exotic state of matter known as a quark-gluon plasma (QGP), in which hundreds of ordinary protons and neutrons melt together and form a fiery soup of free-roaming quarks and gluons. The universe consisted of such a quark stew 10 microseconds after the big bang, about 15 billion years ago.

Seven experiments have been gathering data for the past six years at CERN, the European laboratory for particle physics near Geneva. Although the accumulated evidence is not as direct and clear-cut as had been hoped for when the program began, scientists conducting the experiments felt sufficiently confident to make their February 10 announcement. "We now have compelling evidence that a new state of matter has been created," said CERN theorist Ulrich Heinz. And that state, he continued, "features many of the characteristics" predicted for a quark-gluon plasma