Physicists at the University of Copenhagen and the ALICE collaboration at CERN have achieved a breakthrough in understanding the earliest moments of our Universe. By smashing neon-20 and oxygen-16 atomic nuclei together at near light speed, the research team successfully recreated quark-gluon plasma. This substance is the hot, dense soup of particles that filled the cosmos within the first millionth of a second after the Big Bang.
Previously, scientists believed that creating this primordial matter required much heavier atomic nuclei like lead. This new experiment demonstrates that smaller nuclei can generate these conditions, opening a path to study nuclear structures with high-energy collisions. The team observed that the movement patterns of the resulting particles act as a mirror for the shape of the colliding nuclei.
While oxygen nuclei produce a rounded collision pattern, neon nuclei create a distinct bowling-pin shape. This method functions similarly to casting a shadow to reveal the form of an object that cannot be seen directly. By analyzing these particle trajectories, researchers gain specific information about how protons and neutrons are organized within an atom.
This work advances our knowledge of the strong force, one of the four fundamental forces of nature. The team at the Niels Bohr Institute is already planning to test even lighter nuclei, such as helium-4, to determine the exact boundaries of when this state of matter can emerge. These experiments bridge the gap between nuclear physics and cosmology, showing how the internal architecture of atoms relates to the initial expansion of the Universe.