Color-glass condensate was an unexpected discovery made during proton-lead collisions, intended to act as a reference to compare with other types of collisions. Scientists saw a fluid wave of gluons, elementary particles that "glue" together the quarks together inside neutrons and protons. New particles are produced by the collisions between the lead ions and protons. As expected, the majority of the new particles speed off in all directions. However, some pairs of particles appear to depart the collision in correlated directions. Why do gluons in the color-glass condensate direct particles to travel in the same direction? It may be related to the phenomenon called quantum entanglement, which is when a pair of particles retain a connection or become entangled even when they are separated.
Details of the discovery will be published in the journal Physical Review B.
Photo: Large Hadron Collider or LHC (Maximilien Brice, CERN)