Glueballs?

A particle purely made of nuclear force

For decades,scientists have been looking for so-called "glueballs". Now it seems
they have been found at last. A glueball is an exotic particle, made up
entirely of gluons – the "sticky" particles that keep nuclear particles
together. Glueballs are unstable and can only be detected indirectly, by
analysing their decay. This decay process, however, is not yet fully
understood.

Professor Anton Rebhan and Frederic Brünner from TU Wien (Vienna)
have now employed a new theoretical approach to calculate glueball
decay. Their results agree extremely well with data from particle
accelerator experiments. This is strong evidence that a resonance called
"f0(1710)", which has been found in various experiments, is in fact the
long-sought glueball. Further experimental results are to be expected
in the next few months.

The Standard Model is very messy....