Physicists find new evidence for glueballs, a particle made entirely of gluons

New Evidence for Glueballs

Physicists involved with the Beijing Spectrometer III (BES III) experiment have reported new evidence for the existence of glueballs. These are composite particles theorized to be made entirely of gluons, which are carriers of the nuclear strong force. The findings were detailed in a preprint on arXiv and presented at the International Conference on High Energy Physics (ICHEP).

The Role of Glueballs in Physics

The Standard Model of Particle Physics predicts the existence of glueballs as a direct consequence of quantum chromodynamics, the theory governing the strong nuclear force. While the Higgs boson was considered the final missing piece of the Standard Model upon its discovery, glueballs represent another fundamental aspect of particle physics that has remained unconfirmed.

Glueballs contribute to the mass of matter, similar to the Higgs boson. Most of the mass in protons and neutrons comes from the energy involved in the strong force binding quarks together via gluons, rather than from the quarks themselves. Gluons can also bind to each other, theoretically forming particles composed solely of gluons.

Experimental Search for Glueballs

The search for glueballs often focuses on the decay products of particles like the J/ψ particle, discovered in 1974. This meson, composed of a charm quark and a charm antiquark, produces a large number of gluons and hadrons when it decays, making it a suitable environment for detecting glueballs.