Review: The Particle at the End of the Universe by Sean Carroll
Sean Carroll is both a scientist and science-writer, combining the inside knowledge of a particle physicist with the skills of a storyteller. This combination of talents gives a unique and valuable perspective to his book about the Higgs Boson and its discovery at the Large Hadron Collider [LHC] in 2012.
The reader will cover a lot of ground in Carroll's company, getting a potted history of 20th century physics and joining the author in the heroic task of explaining the Higgs itself. This is the most esoteric beast in the "particle zoo" of modern physics and its job is to sneak past an esoteric roadblock encountered on the road to a fundamental description of nature. Even for physics students the resulting "Standard Model" is an intellectual Everest and a non-mathematical account of the Higgs is like tackling that Everest without oxygen, but the description here is as good as any you will find. (There's a reason why physicists use math -- it's not there to make it harder, but to make it easier.)
The book's (few) shortcomings also reflect its mixed heritage. The prose is overly adjectival in places, in a way that is more typical of journalese than scientific writing. And there is possibly a surfeit of back-story, displaying an academic thoroughness at the price of a large cast of characters and a welter of detail. It is all interesting, but perhaps not all crucial to understanding the Higgs and its discovery.
Particle physics is a human story as much as a science story. One widely repeated anecdote tells of a team working on an experiment in the 1970s who were baffled as to why their equipment went haywire each evening. According to legend, they eventually rigged a video camera - and caught the leader of the rival group making stealthy visits to urinate on their detector as he knocked off for the evening. This story is (I hope!) apocryphal, but its very existence and the glee with which it's retold bear witness to the epic rivalries that litter the field.
By contrast, Carroll portrays the vast collaboration that funds, constructs and operates the LHC as a functional community. This is a huge achievement in its own right, given that the LHC is the most complex machine devised by human beings. The titanic egos of the past are less visible at the LHC or, more likely, better harnessed to the common good. There may be colourful stories to be told, but as yet there are no books written by LHC insiders -- apparently theoreticians like Carroll have more time on their hands.
Like many science writers, Carroll underlines the mana of the Nobel by explicitly identifying winners when they appear in the text, as if they were saints in a religious history. Always Saint Peter, never just Peter and always "Nobel Prize winner Weinberg", never just "Weinberg". Success may have a thousand fathers, but the Nobel Prize only recognizes three at a time; so, although many scientists collaborated to find the Higgs, there will always be a sharp distinction between team and individual when Nobel prizes are handed out. This year's prize went to the ideas underlying the Higgs, rather than the experimentalists who discovered it. Carroll delves carefully into this history, which hinges upon a sequence of papers written in 1964 -- almost 50 years ago.
The Higgs is named for Peter Higgs, a Scottish physicist, and there was never any doubt that he would be among those called to Stockholm. Work by Brout and Englert was also deemed worthy and the pair's surviving author, Englert, shared the prize with Higgs. This choice left a third group – Gerry Guralnik, Carl Hagen and Tom Kibble – waiting at the door. GHK were the last to publish but their discussion was the most comprehensive, but the three of them could only have won at the expense of Higgs himself given that no more than three people can share the prize. Physicists are likely to bicker over which group was the most worthy of recognition for years.
Carroll is a prominent blogger and tweeter (and co-founded the pioneering but now-dormant group blog, Cosmic Variance) and he does a great job of capturing the feedback between the conventional scientific process and the new world of blogs and tweets. This is a key part of the story, as the size of the collaborations ensure that thousands of people were in the know, so the rumour mill cranked up to a dizzying speed as the hunt progressed. Moreover, the Higgs was not found in a single Eureka moment but after a long slog to differentiate a signal from the ``background'', further hiking the tension.
The definitive announcement came on July 4, 2012 in a scheduled media event. It was clear that something was up, and the physics community speculated endlessly about whether it would be an "announcement" or just an "update". Everyone seemed to know somebody who knew something. My personal inside track was via Gerry Guralnik, whom I know from my time as a post-doc at Brown University. We were swapping email in late June, and Gerry mentioned that he was heading to Geneva for the 4th. He didn't know exactly what would be said, but if it was enough to get Gerry on a plane it was clearly going to interesting. I kept this snippet to myself, but a week later later the Daily Mail reported that most of the surviving inventors of the Higgs would be in Geneva, and my discretion was rendered academic.
From a working theoretical physicist, questions about the utility of particle physics are surely rhetorical, but the money involved means they need to be asked. Carroll poses this question toward the end of the book, and eventually answers it by quoting Robert Wilson, the founder of Fermilab which is the nearest rival to the LHC. Testifying before the US Congress, Wilson was asked if particle physics would contribute to national defence and he replied that it was no use at all. Pressed, he placed the exploration of the physical world alongside poetry and painting, stating that particle physics "has nothing to do with defending our country expect to make it worth defending."
Carroll also extols the spin-offs from particle physics, from better electronics to the world wide web itself. Of course another, albeit smaller, by-product of the search for the Higgs has been a bumper crop of books (this, this and this, for instance), and The Particle at the End of the Universe is one of the best. Carroll's account provides an excellent account of what we have learnt about the particle realm, capturing the excitement of the hunt and the grandeur of what has been discovered.
POSTSCRIPT: Yep, first blog in a long time -- always planned on this as an occasional thing, rather than adding another deadline to my life. This review is also published on Sciblogs.co.nz. And, full disclosure, Sean and I know each other -- physics is a small world.