Quarks and gluons are sub-atomic particles - some of the building blocks of matter. In the state known as quark-gluon plasma, they are freed of their attraction to one another. This plasma is believed to have existed just after the Big Bang.

He explained that by studying the plasma, physicists hoped to learn more about the so-called strong force - the force that binds the nuclei of atoms together and that is responsible for 98% of their mass.