Such a collision should produce so much energy that protons and neutrons in the lead would disintegrate into their constituent quarks and gluons, which would be drastically compressed. Under those circumstances, quarks and gluons are expected to behave in weird ways, thanks to a counterintuitive peculiarity of nuclear physics. The more familiar fundamental forces of nature, such as gravity or magnetism, get weaker over distance. It is this plasma that is thought to have filled the nascent universe microseconds after the Big Bang. As that plasma cools, the quarks would recombine into new forms, including numerous mesons.
Mesons are unstable and break up almost immediately.
But CERN's detectors are able to discern the particular types of mesons emitted around the nuclear crash site. And the distinctive proportions of the different types, the scientists said, were exactly what theory predicted would result from the plasma condition. The data from any one experiment is not enough to give the full picture, but the combined results from all experiments agree and fit. Making a 'Little Bang' CERN scientists smashed lead nuclei together in an attempt to re-create the start of the universe. Nuclear particle made up of two up quarks and a down quark, has positive charge.