Nuclear Matter in Extremis Sought with Ultrarelativistic Heavy‐Ion Beams

Last summer's Quark Matter '87 conference, at Schloss Nordkirchen near Dortmund, was the sixth in a series of quasiannual gatherings of physicists interested in extended nuclear matter under extreme conditions of density and temperature. But it was the first that had significant data to chew on. At sufficiently high energy densities, it is confidently believed, we will reach the Holy Grail—the phase transition from ordinary nuclear matter to the “quark‐gluon plasma.” (See PHYSICS TODAY, March 1985, page 40.) The experimental method of choice is to bang heavy nuclei together at the highest possible collision energies. Before September 1986 the best one could do (aside from examining a handful of spectacular cosmic‐ray events) was to accelerate uranium ions to a modest 1 GeV per nucleon at the Berkeley Bevalac and fire them at a uranium target.