On the morning of 4 July 2012, students who had queued overnight in the corridors of CERN, sleeping bags and all, filed into the main auditorium as if into a rock concert. On stage, the leaders of the two great experiments — Fabiola Gianotti for ATLAS, presenting, to physicists' lasting amusement, in the Comic Sans font, and Joe Incandela for CMS — walked through their data until each arrived at the same small bump in the same place. When the statistical significance flashed up as five sigma, the room erupted. In the audience sat Peter Higgs, then 83, who took off his glasses and wiped away a tear, remarking that he had never expected the discovery to come in his lifetime. CERN's director-general told the room that, speaking as a layman, he thought they had it.
'It' had been 48 years in the finding. In the autumn of 1964, three groups independently cracked the same puzzle: how the carriers of the weak nuclear force could be heavy when the underlying mathematics seemed to insist they be massless. Robert Brout and François Englert in Brussels published first, in August; Peter Higgs in Edinburgh followed in October; Gerald Guralnik, Carl Hagen and Tom Kibble completed the trio in November. The shared answer was an invisible field filling all of space, with particles acquiring mass through their interaction with it — the more strongly they couple, the heavier they are. Higgs's short paper was initially rejected by the journal Physics Letters, then edited at CERN of all places, as lacking obvious relevance to physics. Stung, he added a paragraph noting that the theory implied a new massive particle, and sent it to Physical Review Letters instead. That afterthought paragraph is why the boson carries his name.
The particle acquired a second, more troublesome name in 1993, when the Nobel laureate Leon Lederman published a book calling it the God Particle. Lederman claimed he had wanted to call it the 'goddamn particle', in honour of its refusal to be found, and that his publisher balked. Physicists have winced ever since — Higgs, an atheist, disliked the label — but the nickname sold newspapers, and arguably helped sell the machines needed for the hunt.
The machine
That hunt required the largest scientific instrument ever constructed. The Large Hadron Collider is a 27-kilometre ring buried about 100 metres beneath the Franco-Swiss border near Geneva, in which protons lap the circuit more than 11,000 times a second at within a whisker of the speed of light, steered by superconducting magnets chilled to 1.9 degrees above absolute zero — colder than deep space. Its path to glory was bumpy: first beam on 10 September 2008, then, nine days later, a faulty electrical connection, a violent helium leak and more than a year of repairs. The field had been left to Europe partly by default, after America's rival Superconducting Super Collider — planned at 87 kilometres around, in Texas — was cancelled by Congress in 1993 with its tunnels partly dug. Crucially, the LHC ran two independent, deliberately rival detectors, ATLAS and CMS, whose teams were kept apart so that a fluke in one could not masquerade as a discovery in both. Five sigma — odds of roughly one in 3.5 million that the bump was mere chance — was demanded of each separately, and delivered by both, at a mass of about 125 gigaelectronvolts, some 133 times the mass of a proton.
The reluctant laureate
On 8 October 2013, after an uncharacteristic delay of an hour, the Nobel committee awarded the physics prize to Englert and Higgs; Brout had died in 2011, and under the Nobel Foundation's current rules a prize cannot be awarded posthumously unless the laureate dies after the announcement. Higgs, dreading the attention, had slipped out of his Edinburgh flat that morning without a mobile phone — he never carried one — and learned of his prize only when a former neighbour stopped him in the street, on his way home from lunch, to offer congratulations. He spent much of his later life gently protesting that too much of the credit had attached to his name alone, and he died in 2024, aged 94.
The boson itself decays in a fantastically small fraction of a second and touches nobody's daily life directly — except that the field whose existence it certifies gives every electron in every atom its mass. It took humanity 48 years, and the biggest machine it has ever built, to catch the universe in the act of holding everything up.
Quiz nuggets
- The Higgs mechanism was proposed in 1964 by three groups: Englert and Brout published first, Higgs second, and Guralnik, Hagen and Kibble third.
- Peter Higgs's original paper was rejected by Physics Letters; he added the boson prediction and published in Physical Review Letters instead.
- CERN announced the discovery on 4 July 2012, with the ATLAS and CMS experiments each reaching five-sigma significance at a mass of about 125 GeV.
- The nickname 'the God Particle' comes from Leon Lederman's 1993 book — he reportedly wanted to call it the 'goddamn particle'.
- The 2013 Nobel Prize in Physics went to Higgs and Englert; Robert Brout had died in 2011, and current Nobel rules generally rule out posthumous awards.