After months of intense research, CMS and ATLAS finally have announced the observation of one of the rarest and most extreme Standard Model processes ever observed at the LHC: the simultaneous production of four top quarks. Quarks are one of the fundamental building blocks of nature, being the main constituents of protons and neutrons. Currently, we know of six types of quarks, one of which is the top quark. It is the heaviest particle we know of, 100 000 time heavier than the the typically found in protons and neutrons, amounting to a mass almost as large as that of a gold atom. Given that it is so heavy, it is virtually impossible to observe under normal circumstances, but in the highly energetic collisions at the LHC, they are produced in large quantities. Having four of them at the same time is, however, still rare, even at LHC. Yet the extremity of the process makes it especially prone to modification by yet unknown physics ruling the high-energy spectra.
For those reasons, the recent observation is another great success of LHC. In this case, one with a strong Belgian flavour, because the research yielding the CMS discovery has been largely conducted at Ghent university, by the PhD student Niels Van den Bossche and his supervisor Prof. Didar Dobur, supported by the the other members of the Ghent CMS group. Armed with machine learning, physical insight, and, most of all, heroic energy, they made this observation possible in record time, confirming once again the commitment of Belgium, and especially Ghent, to provide world class physics at the forefront of modern science.