It is more than four decades since Peter Higgs predicted the existence of the particle that now carries his name. As the latest, $9 billion search for the Higgs boson gets under way, Ian Sample managed to track down this unassuming physicist to find out how he will feel when he is finally proved right – or wrong
BY THE age of 79, most scientists have put aside the stresses of working life and settled into quiet retirement. For theoretical physicist Peter Higgs, the chance would be a fine thing. With the world’s most powerful particle accelerator about to be switched on at the CERN nuclear physics lab near Geneva, Switzerland, Higgs has become one of the media’s most wanted.
The attention is hardly unexpected. More than 40 years ago, Higgs predicted the existence of a particle that has proved as elusive as it is profound. The Higgs boson helps explain the origin of mass for some of the fundamental building blocks of matter. To the popular press it is the God particle, which the $9 billion (LHC) at CERN was built to discover. If the quest succeeds, many suspect Higgs will be rewarded with a summons to Stockholm.
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Higgs, now emeritus professor of physics at the University of Edinburgh in the UK, is often portrayed as a reclusive genius. Yet when I met him at his apartment in the city, where neat piles of science magazines cover the coffee table, and box sets of classical records sit on shelves alongside art books and figurines, it quickly became clear that this is a clumsy stereotype. To protect himself from a barrage of media calls he rarely answers the phone, and he doesn’t have a computer – a reaction against the old “cash register”-style machines he ran calculations on during his student days. And while he achieved international recognition for his work in the 1960s – wrong-footing some of the finest minds in physics in the process – he later found he was unable to keep up with the field and eventually cut his losses and moved on.
In conversation Higgs, who has two children – Chris, a computer scientist, and Jonny, a jazz musician – is affable and verges on the self-deprecating, as eager to emphasise what he didn’t do as much as what he did. He is unerringly precise, recalling the dates and discussions of meetings years ago as if they were yesterday. And he is still very much involved with physics, attending conferences and meeting up with former colleagues and students.
Higgs made his name with a series of papers, beginning in 1964, which predicted the existence of an energetic field pervading the universe which drags on particles that interact with it, endowing otherwise massless particles with mass. The field, which is thought to have switched on when the universe was just one 10-billionth of a second old, has an associated particle, the Higgs boson.
At first most physicists dismissed the idea. Higgs had reached his conclusions using quantum field theory, which others had written off as outdated. Several heavyweight groups insisted they could prove him wrong. “Most of my colleagues thought I was an idiot for sticking with quantum field theory, but I stuck with it because I didn’t believe it was as dead as they claimed,” he says. “It turned out to be the most important thing I’d done, perhaps the only important thing I’d done.”
“My colleagues thought I was an idiot for sticking with the theory”
He was convinced that his work was sound, but was unclear what it meant for particle physics. Only in the late 1960s, after Higgs had completed a lecture tour of the US, did Steven Weinberg at the Massachusetts Institute of Technology and Abdus Salam at Imperial College London put the theory to good use – to lay down the first building block of the standard model of particle physics by unifying the electromagnetic and weak forces, two of the universe’s four fundamental forces.
From early on, the authorship of the idea behind what we now call the Higgs boson has been controversial. In Belgium, Robert Brout and François Englert had developed a similar idea via a different route, as had a transatlantic trio of Tom Kibble at Imperial College London and two Americans, Gerald Guralnik and Richard Hagen. The Nobel prizewinner Philip Anderson at Princeton University also claims to have “invented” the Higgs boson in 1962.
Higgs says the first he knew of the particle having acquired his name was after a conference at Fermilab in Batavia, Illinois, in 1972. He heard from a colleague that the name “Higgs” had been attached to almost everything to do with theories of mass generation by the conference rapporteur, prominent physicist Ben Lee. “I have to accept that,” Higgs says. “I think I was first to draw attention to the particle associated with it, and I go around pointing out that nothing else in this kind of theory was mine or mine alone.” What Higgs does object to is the label “God particle”. Though himself an atheist, he worries that the title “might offend people who are religious”.
The Fermilab conference cemented Higgs’s position on the world stage, but privately he was struggling and the success was not enough to push him to develop the idea further. “There was a problem for me when the bandwagon started to roll in 1972. Because I’d written an influential paper, people tended to assume I understood far more about the subsequent theory than I did and I found it increasingly hard to keep up. There were personal issues involved in that too. The same year, my wife and I broke up, though we got back together on friendly terms later, so while the news from the conference at Fermilab was good for my morale, I wasn’t in a good state for getting involved with the detailed theoretical work that followed.”
Instead, he changed the focus of his work to the field of supersymmetry, but later found that tough going too. “I realised the only people who were producing anything that was worth doing was the generation that had just got their PhDs. After some years, I gave up. I was sad about it. If I’d done more maths at university I might have had the right background to do it.”
Though Higgs was no longer a major player in the field, instead devoting time to teaching and supervising, he closely followed the hunt for his particle at CERN and Fermilab. Along the way, he became anxious at what he sees as scientists overselling the need to find the Higgs. In 2000, his fears were realised when CERN’s previous collider, before finding the Higgs, prompting the headline: “God particle disappears down £6bn drain” in The Times of London. “It was a comeuppance for people who’d oversold the machine on something it might not find,” says Higgs, “and people are still doing that now.”
There are plenty of theories describing what the Higgs boson will look like. Higgs himself suspects it might turn out to be a number of supersymmetric composite particles, rather than a single irreducible one. That would be the first major success to take physics beyond the confines of the standard model and raise hopes of finally paring down the unwieldy set of competing models known as string theory, which many physicists see as a route to an all-encompassing theory of the universe. “I sit somewhere in the middle on string theory, between those who think it’s the answer to everything and those who write it off completely. Superstring theories have turned out to contain far more than we need for our present universe and that’s the embarrassment of it. I wonder if one day someone will find an intermediate theory that does the job in a better way.”
Earlier this year, Higgs visited CERN for the first proper visit since 1979, and like almost everyone who has seen the LHC he was impressed by its sheer scale. How confident is he that the machine will find his particle? “What I suspect will happen is that the signal will be there in the LHC data, but it will take a couple of years to recognise it, because it’s a formidable problem of data analysis. Equally it may be already in Fermilab’s data,” he says. “If they do find it, it’ll be a relief.”
But what if the Higgs boson is not detected, or Higgs’s theory is proved wrong? “I’ll be very surprised if they don’t find it. If someone shows it’s wrong, I’ll be rather sad but also very puzzled,” he says. “Then I suppose my life will go a little quiet, I shan’t be pestered so much.”
The LHC is scheduled to run for at least 20 years, but Higgs says funds for its planned successor, the , need to be put in place now to ensure it will be ready to take over. He urges scientists not to repeat the mistakes of the past by overselling it as a machine destined to find definite answers to the remaining mysteries of the universe.
As the world waits for the first particles to be smashed together at the LHC, one thing is for sure: Higgs is likely to have a lot more phone calls to ignore.
The Large Hadron Collider – find out more about the world’s biggest experiment in our cutting-edge special report.
Quantum World – Learn more about a weird world in our comprehensive special report.
Profile
Peter Higgs was born in 1929 in Newcastle upon Tyne, north-east England, and won a PhD in molecular physics at King’s College London in 1954. He taught at University College London and the University of Edinburgh, where he was professor of theoretical physics from 1980 to 1996. He was elected a Fellow of the Royal Society in 1983 and was awarded the Dirac medal and prize in 1997. In 2004, he was awarded the Wolf prize alongside Robert Brout and François Englert for pioneering work on mass generation.
