Thousands of scientists were involved in hunting down the Higgs boson, this generation’s greatest discovery in particle physics. But for the committee awarding the Nobel Prize in Physics, two names mattered most. In an announcement on 8 October in Stockholm, Peter Higgs of the University of Edinburgh, UK, and François Englert of the Free University of Brussels were named Nobel laureates for developing the theory of what is now commonly called the Higgs mechanism: the process by which a field pervading space gives other fundamental particles mass, and which implies the existence of the Higgs boson. Regarding the committee’s choice, “I think in all honesty, this is what I would have done,” says John Ellis, a theoretical physicist at CERN, Europe’s particle-physics lab near Geneva, Switzerland.
The existence of the boson was announced to cheers at CERN on 4 July last year, after the particle was fleetingly produced in high-energy collisions at the lab’s €3-billion (US$4.1-billion) Large Hadron Collider. It would have been too complicated to try to honour the experimenters with the Nobel, says Ellis, who joined other CERN theorists in popping open champagne as the award was announced. “Englert and Higgs’ pioneering work richly deserved this prize,” he adds.
“I’m very, very happy to have the recognition of this extraordinary reward,” says Englert. Higgs, who is notoriously modest and suffered a bout of bronchitis last month, made himself unavailable for interviews. The two winners had met for the first time at CERN last July.
The Higgs boson was the missing piece in the standard model of particle physics, which describes all known fundamental particles and forces, apart from gravity. The boson itself is the smallest possible ripple of the Higgs field, which gives mass to particles including electrons, quarks and the W and Z bosons that carry the weak nuclear force.
The idea was mooted in the 1960s, when physicists trying to describe the fundamental forces were wrestling with “embarrassing massless particles floating around in their theories”, as Ellis puts it. In 1964, six physicists independently worked out how a field would resolve the problem. Robert Brout (who died in 2011) and Englert were the first to publish, in August 1964, followed three weeks later by Higgs — the only author, at the time, to allude to the heavy boson that the theory implied. Tom Kibble, Gerald Guralnik and Carl Hagen followed. “Almost nobody paid any attention,” says Ellis — mostly because physicists were unsure how to make calculations using such theories. It was only after 1971, when Gerard ’t Hooft sorted out the mathematics, that citations started shooting up and the quest for the Higgs began in earnest.
So numerous were the theorists involved, that Higgs reputedly referred to the ABEGHHK’tH (Anderson–Brout–Englert–Guralnik–Hagen–Higgs–Kibble–’t Hooft) mechanism. But that list of names is nothing compared with the legion of experimenters who joined the quest to track down the boson, with increasingly powerful particle accelerators that produced their own Nobel-prizewinning findings along the way.
“It’s really an incredible thing that it’s happened in my lifetime,” Higgs told the audience at CERN when the particle was announced.
Alan Walker, a colleague of Higgs at Edinburgh, says, “That day was for the experimentalists. I guess today is for the theorists.”
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