CERN researchers have observed the formation of small droplets of quark-gluon plasma (QGP) in oxygen ion collisions. This finding is significant because, until now, QGP production had been primarily associated with collisions of heavy nuclei, such as lead, where large volumes of this "primordial soup" are generated. The detection of QGP in smaller systems, such as those created by light oxygen nuclei, challenges some previous assumptions about the conditions necessary for its formation.

Quark-gluon plasma is a state of matter that existed in the first microseconds of the universe, when temperatures and densities were so extreme that quarks and gluons were not confined within protons and neutrons but moved freely. Recreating and studying this state in the laboratory allows physicists to better understand quantum chromodynamics (QCD) and the early evolution of the cosmos. The observation in oxygen collisions suggests that system size is not the only determining factor, opening new avenues for exploring the properties of QGP.

The experiments were conducted at CERN's Large Hadron Collider (LHC), where beams of oxygen ions were accelerated and collided at very high energies. Detectors, such as ATLAS or CMS, analyzed the products of these collisions, searching for characteristic signatures of QGP, such as heavy hadron suppression or elliptic flow. The confirmation of these signals in smaller systems expands the range of conditions under which QGP can be studied, which could lead to a more complete understanding of its thermodynamic and transport properties.