Two protons enter from opposite sides of a 27-km tunnel under the French–Swiss border, each carrying so much energy that, for an instant inside the collision, the universe is briefly hotter than it has been since 10⁻¹² seconds after the Big Bang.
$$ p\,p \rightarrow H \rightarrow \gamma\gamma,\, ZZ^*,\, WW^*,\, b\bar{b},\, \tau\bar{\tau} $$
What you see is the transverse view: the page is the slice of the detector perpendicular to the beam line. Charged particles spiral inside a 3.8 T solenoid — positive charges curve one way, negative the other. Their curvature radius gives you the momentum:
$$ r = \frac{p_T}{|q|\,B} $$
Crank the magnetic field slider up and the spirals tighten. Push the energy slider and the tracks shoot further before they curl. The number of tracks is set by hand here; in real life it's set by the gory innards of QCD and the "branching ratios" of whatever state was produced.
We discovered the Higgs by counting events like this — millions of them — and watching for the tiny excess of two-photon pairs near 125 GeV. Counting is a deeply unromantic verb for something that took 50 years and 10,000 people.