CERN finds gluons behaving strangely deep inside atomic nuclei

Physicists at CERN have found a new way to peer deep inside atomic nuclei and distinguish between two competing explanations for how gluons behave. Using the ALICE experiment at the Large Hadron Collider, researchers measured particle production at record-setting spatial resolution, revealing structures as small as about one-quarter the size of a proton. At the smallest scales, they saw a surprising drop in J/ψ production that conventional “nuclear shadowing” struggles to explain.

CERN finds gluons behaving strangely deep inside atomic nuclei. University of Kansas physicist Daniel Tapia Takaki played a leading role in the study, which was conducted as part of the ALICE experiment at CERN’s Large Hadron Collider and published in Physical Review Letters. The researchers report the first multidimensional measurement of incoherent J/ψ (pronounced "JAY-sigh") photonuclear production that tracks both interaction energy and momentum transfer.

Together, those measurements allow scientists to examine how gluons are distributed inside atomic nuclei with record-setting detail. Why Gluons Matter Gluons are particles that help bind quarks together through the strong force. Although quarks are commonly described as the fundamental pieces of protons and neutrons, much of the mass of ordinary matter comes from the energy associated with gluons and the strong force.