Topponium: the new physics we nearly missed!

The greatest success of the LHC has been to dispel the myth that hadron colliders are not precision physics machines. From the discovery of the Higgs boson, the measurement of the W boson mass, the discovery of dozens of new bound states, and now the observation of subtle and elusive QCD pseudo-bound state of topponium, the LHC has probed the SM to unprecedented precision. In this seminar I will give an overview of the history of precision top properties measurements at the LHC and how they lead to the discovery of a new pseudo-bound state at the very threshold of ttbar production by the ATLAS and CMS experiments. I will also use this discovery as both an example and a caution about the limitations in current experimental particle physics techniques and highlight the steps that must be taken to exploit the forthcoming HL-LHC to it’s full potential if we are to have a chance to discover physics beyond the Standard Model.