The Standard Model of particle physics predicts the existence of glue-balls, which are particles made from gluons. Gluons are force particles that hold quarks together. Without them, the nuclei of atoms would fall apart. Scientists are pretty sure that gluons could come together themselves to form these glue-balls, but thus far, none have been found. The best way to prove their existence would be to search for and analyze their decay, and some research teams are doing just that. However, because no one knows what exactly to look for, the hunt for glue-balls is a difficult one.
Glue-balls are subatomic particles made from gluons, which typically keep the nuclei of atoms together.
The existence of glue-balls is predicted by the Standard Model of particle physics, and observing them would help to confirm that the model is correct.
There are a couple particles that scientists have analyzed that could be glue-balls, notably f0 (1500) and f0 (1710).