The primordial particles of matter that existed just after the big bang are now being re-created in the Large Hadron Collider (LHC) to advance understanding of the kind of matter that existed in the first seconds of the universe. Seconds after the big bang, quarks and gluons — basic building blocks of matter — were not confined inside composite particles such as protons and neutrons as they are today. Instead, they moved freely in a state of matter known as quark-gluon plasma.

Now, experiments using heavy ions at CERN’s LHC have re-created, for a fleeting moment, conditions similar to those of the early universe. By examining more than 1 billion lead ion collisions, collaboration experiments have enabled precise measurements of the properties of matter under these extreme conditions. The findings are based on the four-week LHC run with lead ions in 2011.