CERN scientists observe unusual gluon behavior inside atomic nuclei
Physicists working on the ALICE experiment at CERN's Large Hadron Collider have obtained one of the most detailed views yet of how gluons behave inside atomic nuclei. The findings point to an effect that could help scientists better understand matter at extremely small scales.
Gluons are elementary particles that carry the strong force between quarks inside protons and neutrons. Understanding their behavior is therefore fundamental to explaining the internal structure of ordinary matter.
Large Hadron Collider probes structures smaller than a proton
In the ALICE experiment, researchers studied interactions involving lead nuclei moving at extremely high speeds. Their intense electromagnetic fields acted as sources of high-energy photons, allowing scientists to investigate the distribution of gluons inside the nuclei.
The researchers were able to probe structures around 0.2 femtometers across, roughly four times smaller than a proton. At the smallest scales, they observed an unexpected decrease in J/ψ particle production. The result reached a statistical significance of approximately three standard deviations.
The observation is difficult to explain entirely through the conventional effect known as nuclear shadowing. Instead, the data are consistent with gluon saturation, a phenomenon in which gluons at extremely high densities begin interacting more strongly with one another, limiting further growth in their numbers.
The research was published in Physical Review Letters. If future experiments confirm the observation, it could help physicists build a more precise understanding of the strong force and the internal structure of atomic nuclei.
