The Large Hadron Collider is the most complex machine ever built. What it has discovered so far and what the future FCC — four times larger — will search for.
📖 Read more: Higgs Boson: Why Do They Call It the 'God Particle'?
⚙️ The Largest Machine in the World
The Large Hadron Collider (LHC) sits 100 metres underground on the Franco-Swiss border near Geneva. With a circumference of 26,659 m (roughly 27 km), it is the world's largest and most powerful particle accelerator. Two beams of protons travel in opposite directions, guided by 1,232 superconducting dipole magnets (15 m each) operating at 1.9 K (−271.3 °C) — colder than outer space. In total, 9,593 magnets steer and focus the beams.
Each beam contains 2,808 bunches of $1.2 \times 10^{11}$ protons each, making 11,245 turns per second. As CERN describes: "The particles are so tiny that the task of making them collide is akin to firing two needles 10 kilometres apart with such precision that they meet halfway." Nine experiments operate at the LHC — the main ones are ATLAS, CMS, ALICE and LHCb.
⭐ July 4, 2012 — The Higgs Boson
In 1964, Robert Brout, François Englert and Peter Higgs proposed a mechanism explaining how elementary particles acquire mass. As CERN states: "When the universe began, no particles had mass — they all sped around at the speed of light. Stars, planets and life could only emerge because particles gained their mass from a fundamental field associated with the Higgs boson."
On July 4, 2012, the ATLAS and CMS experiments announced the discovery of a new particle to a packed auditorium at CERN. Its mass: roughly 125 GeV. It is the only known elementary particle with zero spin, appearing in about one in a billion collisions. In October 2013, the Nobel Prize in Physics was awarded to Englert and Higgs. By the end of Run 3, approximately 55 million Higgs bosons had been produced.
⚖️ How the Higgs Field Gives Mass
58% of Higgs bosons decay into bottom quark pairs — the most likely decay channel but also the hardest to measure, definitively observed in 2018. Photons do not interact with the Higgs field — which is why they are massless.
🪩 Exotic Particles and Quark-Gluon Plasma
In July 2022, LHCb discovered three new exotic particles: a pentaquark containing a strange quark (significance 15σ) and the first pair of tetraquarks, including one with double electric charge.
📖 Read more: The Standard Model: The Map of All Known Particles
"We're witnessing a period of discovery similar to the 1950s, when a 'particle zoo' of hadrons started being discovered and ultimately led to the quark model. We're creating 'particle zoo 2.0'."
— Niels Tuning, LHCb physics coordinator (July 2022)In heavy-ion collisions (lead nuclei), ALICE recreates conditions from microseconds after the Big Bang. Quark-gluon plasma (QGP) behaves as a perfect fluid with minimal viscosity — not a gas as expected. Jet quenching was confirmed: particle jets lose energy passing through the fireball, which is 30–50 times denser than an ordinary nucleus.
🔭 Run 3 and the Future: HL-LHC
In July 2022, Run 3 began at a record energy of 13.6 TeV. By the end of 2025, the LHC had delivered 500 inverse femtobarns of integrated luminosity (1 fb⁻¹ ≈ 100 trillion collisions), and in December 2025 it surpassed 1 exabyte of stored data.
From mid-2030, the High-Luminosity LHC (HL-LHC) will operate after replacing 1.2 km of the LHC with innovative components. It will boost luminosity 10-fold, reaching 140–200 collisions per bunch crossing (vs ~60 today). Target: 380 million Higgs bosons and 4,000 fb⁻¹ total luminosity.
🌍 FCC — The Successor
LHC vs FCC
| Feature | LHC | FCC-hh |
|---|---|---|
| Circumference | 27 km | 90.7 km |
| Collision energy | 13.6 TeV | 100 TeV |
| Access shafts | 4 | 8 |
| Cost | 4.3 bn CHF | 15 bn CHF (FCC-ee) |
| Operation | 2008 – present | Late 2040s (ee) / 2070s (hh) |
The Future Circular Collider (FCC) will feature a 90.7 km tunnel at depths of 180–400 metres. The feasibility study was delivered in March 2025, with a decision expected in 2028. It will first operate as FCC-ee (electron-positron) for precision measurements (~15 years), then as FCC-hh with 100 TeV proton collisions (~25 years), with a programme running until the end of the 21st century. Over 140 institutes in 30+ countries are involved.
Since 2008, the LHC has reshaped our understanding of the fundamental structure of the universe — and the greatest questions remain open: dark matter, matter-antimatter asymmetry, supersymmetry. With the FCC, humanity will have the tool to reach energies far beyond the LHC — perhaps that is where the answers hide.