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IN HIS latest book Elusive, Close sets out to write about Peter Higgs, whose belief in the detectability of a very special particle that was to bear his name earned him a Nobel prize in 2013.
But Higgs鈥檚 life resists narrative. He has had a successful career. His colleagues enjoy his company. He didn鈥檛 over-publish or get into pointless spats. Now in his mid-nineties, Higgs keeps his own counsel and doesn鈥檛 use email.
So that left Close with writing a biography not of the man, but of 鈥渉is鈥� particle, the Higgs boson 鈥� and with answering key questions, such as how do we explain fundamental forces that can鈥檛 reach outside the nucleus of an atom? What was so compelling about our explanation it was worth inventing a fundamental field we couldn鈥檛 detect? Why did this idea occur to six thinkers, independently, in 1964? And how did it justify a cool 鈧�10 billion to hunt for the particle that this conjectural field predicted?
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It is all in Close鈥檚 excellent book, but you have to work hard. Let鈥檚 start with our universe. Forget solid matter for a moment, think fields. The universe is full of them, and if we disturb these fields it is as though we dropped a stone into a lake 鈥� we make waves. In this analogy, which is a favourite of the physicist Sean Carroll, there is no 鈥渙utside鈥� from which you can see the whole wave. Instead, as the wave passes through a point in space, you will notice a fluctuation in energy at that point.
These changes show up as particles. Light, for example, is a wave in the electromagnetic field, yet when we observe the effect that wave has on a point in space, we detect a particle 鈥� a photon. Some waves are easier to make than others, and travel farther. Light waves travel outwards as fast as the universe allows. Gravitational waves are just as fast, but decay sharply with distance.
The mathematics used to model such fields makes sense. But we also need a maths to explain why the other fields we know about are confined to infinitesimally small spaces, extending no farther than the dimensions of the atomic nucleus. For this maths to work, it requires another, more mysterious, infinite field: one that doesn鈥檛 decay with distance, and that always has a value greater than zero. This field interacts with everything bar light.
We call the effect of this field mass. Photons are massless, so travel very fast, while everything else has some mass and therefore travels more slowly. It is easy to set the electromagnetic field trembling 鈥� just light a match. To set off a wave in the mass-generating field, however, takes much more energy.
In 1998, CERN, the world鈥檚 largest particle physics lab, began work on its Large Hadron Collider (LHC), a 27-kilometre-long particle accelerator below the French-Swiss border. More than a decade later, on 4 July 2012, a particle collision in the LHC released such energy that it set off a mass-generating wave. As this wave passed through the machine鈥檚 detectors, a new particle was observed. Physicists confirmed the existence of the mass-generating field and our model of how the universe works (the standard model) was completed.
Ultimately, both Higgs and his particle remain elusive. Newcomers should start elsewhere 鈥� perhaps with Carroll鈥檚 fine webinars and books. But Close, and this difficult, brilliant book, will be waiting.
