“However, last year, while analyzing a large dataset of top quark–antiquark production from 2016 to 2018 in search of new types of Higgs bosons, CMS researchers spotted an unexpected surplus of top quark–antiquark pairs,

which are often seen as a smoking gun for the presence of undiscovered particles.

That excess occurred precisely at the minimum energy required to produce such a pair of top quarks, a threshold where the formation of a quasi-bound state becomes more likely.

This led the team to consider an alternative hypothesis, a fleeting union of a top quark and antiquark, which was long thought too elusive to detect at the LHC. ATLAS has confirmed that the same effect exists in its data, thus ruling out simpler explanations and aligning closely with CMS’s findings.

As it turns out, top quark–antiquark pairs can linger just long enough to briefly bind into a toponium state, an interaction mediated by gluons, the messengers of the strong nuclear force.”

https://interestingengineering.com/science/particle-accelerator-reveals-rare-top-quark-dance