2.5 millennia ago Democritus had the first great vision: “Atoms are indivisible, elementary grains of reality”. He had a sound argument, here his Gedankenexperiment: “Imagine that you break up a piece of matter ad infinitum. What would be left?”

He goes on: “Just as by combining letters of the alphabet in different ways we may obtain comedies or tragedies, ridiculous stories or epic poems, so elementary atoms combine to produce the world in its endless variety.” [Carlo Rovelli, “Reality Is Not What It Seems.”]

It took 2.5 millennia to experimentally confirm this. (Einstein in 1905 on Brownian motion)

Experimental inconsistencies (Michelson-Morley experiment, black body radiation) led to the great revolutions of special relativity and quantum mechanics. Nowadays we understand Newtonian physics as an approximation of relativity for low speeds (compared to c), and an approximation of quantum mechanics for large sizes (as compared to the size of an atom).

“And probably everything that we know today, is an approximation of something else that we don’t yet know.” [Carlo Rovelli, “Reality Is Not What It Seems.”]

In analogy, the Standard Model (SM) is like Newtonian physics – a success story: it describes all visible matter, all forces (with the exception of the gravitational force) and it describes how elementary particles acquire a mass (Higgs mechanism). All predictions are verified by experiment with excellent precision for more than 50 years. The last piece to this puzzle was added in 2012: the Higgs boson discovery.

Now we try to test the limits of this SM to find an inconsistency, a clue of physics Beyond the Standard Model (BSM). While Michelson-Morley and the black body conundrum led the way to high speeds and small sizes, respectively, we now push to high energies, where we expect a new theory to reveal itself...

The LHC provides a unique opportunity to explore this high-energy frontier to pioneer Terra Incognita.