The announcement of the discovery of the Higgs boson on July 4, 2012, at CERN, the European center for particle physics, was a strange scientific jubilee. Reporters and scientists crammed into the auditorium to hear about the revelation. There was a party atmosphere, with wild applause interrupting presentations by the researchers who had done the experiments. Peter Higgs, the then eighty-three-year-old British physicist whose work in 1964 led him to propose this elusive fundamental part, was in the audience and, shedding a tear or two, said: “It’s a really incredible thing that it’s happened in my lifetime”. Yet aside from the experts, hardly anyone understood what the fuss was about.
“All the journalists are begging for layman’s terms”, the Guardian‘s live blog confessed. “Rolf Heuer [director-general] of CERN is trying all kinds of inventive allegories to explain the discovery. Is it working? Not entirely sure.” Some reporters resorted to ridiculing the scientists for presenting their findings in Comic Sans.
The discovery of the Higgs was a scientific triumph that relied on Herculean engineering and dogged persistence. But its unveiling was not the finest day for the relationship between science and society. There was a hint of the emperor’s new clothes as the media whipped themselves into a frenzy without really knowing why. How could the billions of euros spent on the Large Hadron Collider (LHC), the particle accelerator at CERN that made the discovery possible, be justified if only specialists could appreciate what it was for?
The physicist Frank Close’s thorough and characteristically reliable joint biography of Higgs and the particle named for him doesn’t resolve these questions. In explaining what the Higgs boson is, how it came to be proposed and how it was summoned from furiously energetic collisions, Close sometimes asks a lot of his reader. To say that his description of Goldstone modes and gauge invariance would have been handy when I was struggling to learn quantum field theory as a physics PhD student will give an idea of the book’s level. It’s not for the fainthearted.
But Close is a seasoned communicator of physics. He draws on the many attempts made around the time of the CERN discovery to explain the particle with accessible analogies. At the root of the matter is the Standard Model of particle physics, developed in the second half of the twentieth century, which collects together all known particles and forces. These include the electrons, neutrons and protons that are the constituents of atoms, as well as the more exotic particles that physicists (to their surprise) identified in high-energy particle collisions, such as muons and neutrinos. Protons and neutrons themselves are composites of more fundamental components called quarks, which come in six varieties. And there are four fundamental forces: gravity, electromagnetism and the strong and weak forces that operate inside atomic nuclei.
Most of these particles have mass – which is why we do too. The basic particle of light, called the photon, does not. In the 1970s physicists showed that the electromagnetic and weak forces were once – in the first instants of the Big Bang, 13.8 billion years ago – the same force, which then split into two varieties. But while the photons associated with electromagnetism have no mass, the particles associated with the weak force, called W and Z bosons and discovered in 1983, are decidedly massive: about as much as a single atom of iron. Where did that mass come from?
The Higgs boson is the answer. Just as the photon is the particle associated with an electromagnetic field, so the Higgs has a corresponding field: the Higgs field, which permeates all of space. Even now, no one knows what the Higgs field is exactly – does it have its own deeper structure, say, or is it a featureless continuum? “For now, all we know is its effect”, writes Close: it is the source of the mass of fundamental particles. Particles that have mass “feel” the Higgs field and are slowed down by it. When the LHC was being built in the 1990s with the principal (though not sole) goal of finding the Higgs, the British science minister William Waldegrave offered a bottle of vintage champagne for the best lay explanation of the Higgs, so that voters could understand why the government was helping fund the European project. The winning effort came from a physics professor who compared the Higgs field to the way lackeys would surround Margaret Thatcher when she entered a room, slowing down her progress as she crossed the floor.
While it’s a little too simplistic to say that the Higgs is the origin of all mass, this “Higgs mechanism” seemed vital for making sense of the Standard Model. By the 2010s it was the last remaining piece of the puzzle that experimental evidence was yet to confirm. There was already indirect evidence that the Higgs existed, and estimates of how massive it could be showed that the LHC was the only particle accelerator in the world that could create collisions energetic enough to produce it. The bigger a particle’s mass, the more energy is needed to conjure it out of the Higgs field. With a twenty-seven-kilometre-long accelerator tunnel for speeding up beams of protons to within a whisker of the speed of light, the LHC seemed likely to reach the hazily known threshold.
How Higgs came up with the idea of this mechanism is a fascinating and somewhat poignant tale. He has always maintained that it was the only good idea he ever had – and this is not false modesty. It’s not clear if even he was initially aware of what he had done in his two key papers of 1964; it took him and others some time to appreciate that his solution to a recondite conundrum was in fact a fundamental theory of how some gain particles their mass. He was not, moreover, the only person to have the idea for what became known as the Higgs field: five others did so around the same time, the most significant contribution coming from François Englert (who shared Higgs’s Nobel prize in 2013) and Robert Brout (who died in 2011). Close explains that Higgs’s name alone became associated with the theory partly because of an accidentally erroneous citation, although Higgs does deserve sole credit for recognizing that the theory implied the existence of a new particle that might be detectable.
The work brought him little recognition at first. Because, by his own admission, he lacked the skills to extend his idea to explain other aspects of the Standard Model, Higgs was soon left behind by younger researchers and became a marginal figure, working in the physics department of the University of Edinburgh. Through the 1990s many young particle physicists were surprised to discover that the “Higgs” of this elusive particle was still alive. And that suited Higgs fine: Close’s title refers not just to the particle, but also to the man, who seemed to hate the celebrity and attention forced on him in 2012. When his Nobel prize was announced the following year, he had fled to Leith after sowing a false story about being in the Highlands. The discovery, he later told Close, “ruined my life”.
I suspect Higgs would agree that this reticence does not make him a rich subject for biography. Close perhaps succeeded in writing this book only because, as an expert himself, he earned the man’s trust by interviewing him several times after the discovery. Even then Close has few quotations to adduce, of which none of is particularly scintillating or revealing. Many of the giants of twentieth-century physics – Albert Einstein, Werner Heisenberg, Paul Dirac, Richard Feynman, Robert Oppenheimer, Murray Gell-Mann and (in the popular sphere at least) Stephen Hawking – had lives filled with event, intrigue, controversy and colour. Some were complex and fascinating characters. Higgs has gone out of his way to avoid all that and seems positively eager that we regard him as a tad dull and academically unremarkable. “Let me be frank”, he told Close asked why he had not his own theory further, as others taken later did. “I’m not a very competent theorist when it comes to calculations … When I tried my hand at doing something, I made a fool of myself.”
For all that we crave stories of genius, few scientists, even those who make breakthrough discoveries and win a Nobel prize, can live up to it. Like the writers and artists who produce one great work among mediocrity, they shine for just a moment before the light fades, as if briefly channelling something greater than themselves. What distinguishes Higgs is that he seems to have no wish to bask in an aura of omnipotence. That’s a rare quality, and if it gives Elusive a rather melancholy air, it also means the book offers an unusual representative picture of a life in science. Not everyone’s moment of insight garners a Nobel, but many will agree that such inspiration is fleeting, if it comes at all. The rest can be a frustratingly unremarkable time.
Philip Ball is a science writer. His most recent book is The Book of Minds2022
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