Instead, similar to ice at the melting point, the universe could suddenly undergo a rapid “phase transition”. As it stands, the results indicate that our universe isn’t in a perfectly stable state. Its properties not only determine the masses of elementary particles, but also how stable they are. Experiments at Cern have continued to probe the Higgs boson. Yet the discovery has raised new, fundamental questions. Elementary particles would be massless, there would be no atoms, no humans, no solar systems and no structure in the universe. Without the Higgs boson, the whole theoretical framework describing particle physics at its smallest scales breaks apart. In the following year, Higgs and his collaborator François Englert won the Nobel prize “for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles”. Finally, on July 4 2012, two independent experiments at Cern had each collected enough data to declare the discovery of the Higgs boson. In 2010, the Large Hadron Collider (LHC) began colliding protons with seven times more energy than the Tevatron. In 2011, the Tevatron ceased operations – the Higgs boson escaped detection again. But proton-antiproton collisions produce a lot of debris, making it much harder to extract the signal from the data. The Tevatron collided protons (which, along with neutrons, make up the atomic nucleus) and antiprotons (nearly identical to protons but with opposite charge) with an energy five times higher than what was achieved in Geneva – surely, enough to make the Higgs. Meanwhile, the most ambitious American collider in history, the Tevatron, had started taking data at Fermilab, close to Chicago.

It ran for 11 years, but its maximum energy turned out to be just 5% too low to produce the Higgs boson. The idea was to smash particles together with such high energy that a Higgs particle could be created in a 27km long tunnel at Cern in Geneva, Switzerland – the largest electron-positron (a positron is almost identical to an electron but has opposite charge) collider ever built. It took until 1989 for the first experiment with a serious chance of discovering the Higgs boson to begin its search.

Higgs boson theory