Like quarks, these particles are unobservable in the singlet state due to asymptotic freedom.
In the Peccei-Quinn theory, which seeks a solution to the strong CP problem, the triangle anomaly involving these particles spontaneously breaks symmetry and gives mass to the axion. Evidence for the existence of these particles was deduced from three hadronic jet events with zero total angular momentum using electron-positron collisions in the PETRA experiment, which also determined this particle's spin. Deep inelastic scattering of photons off protons reveal that these neutral particles carry away about half of the proton momentum. Like quarks, these particles are unobservable in the singlet state due to asymptotic freedom. These spin-1 particles are massless and mediate a force described by the SU(3) symmetry group, which results in their carrying a color charge. For 10 points, identify these gauge bosons of QCD, which mediate the strong force.
In the Peccei-Quinn theory, which seeks a solution to the strong CP problem, the triangle anomaly involving these particles spontaneously breaks symmetry and gives mass to the axion.
gluons