Physicists have created a ‘quark soup’ with a temperature of four trillion degrees Celcius – almost as hot as the temperature just after the Big Bang.
The relativistic Heavy Ion Collider (RHIC) smashed gold ions together at nearly the speed of light to create matter at the hottest temperature ever reached in a laboratory. It’s hot enough to melt protons and neutrons into a plasma of quarks and gluons, and about 250,000 times hotter than the center of the Sun.
The quark-gluon plasma, or QGP, is the same substance that filled the universe a few microseconds after it came into existence 13.7 billion years ago.
Although it survives for much less than a billionth of a trillionth of a second, its properties can be determined using RHIC’s detectors to look at the thousands of particles emitted during its brief lifetime.
“There are many ways that photons can be produced in these violent collisions. We were able to ‘eliminate’ the contribution from these other sources by exploiting RHIC’s flexibility to measure them directly and to make the same measurement in collisions of protons, rather than of gold nuclei,” said Barbara Jacak, a professor of physics at Stony Brook University and spokesperson for the PHENIX collaboration.
“Thus we could pin down excess production in the gold-gold collisions, and determine the temperature of the matter that radiated the excess photons. By matching theoretical models of the expanding plasma to the data, we can determine that the initial temperature of the ‘perfect’ liquid has reached about four trillion degrees Celsius.”
Moving forward, Brookhaven physicists are planning to upgrade RHIC over the next few years to increase its collision rate and detector capabilities.
“These technical improvements will facilitate studies of rare signals providing measurements of even better precision on temperature, viscosity, and other basic properties of the nearly perfect liquid quark-gluon plasma created at RHIC,” said Steven Vigdor, Brookhaven’s Associate Laboratory Director for Nuclear and Particle Physics.