FIGURE 19.21 (a) The 3.83 km circumference ring of the Relstivistic Heavy Ion Collider at Brookhaven National Laboratory. Experimental data on the kinetic energy distribution of (b) antiprotons and (c) pions produced in collisions of gold nuclei. These collisions become by far the hottest place in the Solar System for the short times they exist and produce a state of matter, the quark-gluon plasma, which existed for a fraction of a second after the Big Bang. The blue lines represent fits to the kinetic energy distributions using cquation 19.30.