Multigluon

Multigluon is a term used in quantum chromodynamics (QCD) to describe systems, states, or processes that involve more than one gluon. Gluons are the gauge bosons of the SU(3) color gauge group and can interact with each other, enabling color-singlet configurations that do not require valence quarks.

One prominent embodiment of multigluon dynamics is the glueball, a hypothetical bound state composed solely of gluons. Lattice QCD calculations predict a spectrum of glueballs with various total angular momentum, parity, and charge conjugation quantum numbers. The lightest is expected to be a scalar 0++ state around 1.5 to 1.7 GeV, with other low-lying states including 2++ and 0-+. Identifying glueballs in the hadron spectrum is challenging because they can mix with ordinary quark-antiquark mesons that share the same quantum numbers.

In high-energy scattering, processes can be described by exchanges of multiple gluons in a color-singlet configuration. The two-gluon exchange picture is often associated with the Pomeron, which governs diffractive scattering at high energies, while three-gluon exchange is related to the Odderon, a C-odd counterpart. These multi-gluon exchanges form part of the perturbative and nonperturbative descriptions of hadronic interactions.

Beyond bound states and exchanges, dense gluon systems at small Bjorken x or in heavy-ion collisions are treated using multi-gluon correlations and saturation frameworks, such as the Color Glass Condensate, highlighting the central role of multigluon dynamics in QCD phenomena.