At the time before the Big Bang explosion tiny particles existed. They were called quarks and gluons.
The BNL team collided two gold beams, which caused some of the gold ions to explode (thousands per second, on average), producing a very tiny amount of 'freely-flowing' quark-gluon plasma after the gold ions broke apart.
Check out the YouTube animated video of the BNL explosion: 'Hot Quark Soup Produced at RHIC.'
For additional information on this exciting new development in particle physics, pleases read the Brookhaven National Lab article 'New Findings on Hot Quark Soup Produced at RHIC.'
The article states that the U.S. Department of Energy's (DOE) Brookhaven National Laboratory has produced ' '¦ collisions of gold ions traveling at nearly the speed of light [that] have created matter at a temperature of about 4 trillion degrees Celsius '” the hottest temperature ever reached in a laboratory, about 250,000 times hotter than the center of the Sun."
"This temperature, based upon measurements by the PHENIX collaboration at RHIC, is higher than the temperature needed to melt protons and neutrons into a plasma of quarks and gluons. Details of the findings will be published in Physical Review Letters.'
Page four concludes with even higher energies at another particle accelerator/collider that will create even higher temperatures in the very near future.