A Review of Collider: The Search for the World’s Smallest Particles, by Paul Halpern
288 pages
Wiley, 2010

If you haven’t been living under a rock for the past two years, then you’ve probably heard of the Higgs boson. Physicist Peter Higgs predicted the particle’s existence in the 1960s, and in 2012 scientists finally found it with the Large Hadron Collider (LHC) at CERN. The discovery made headlines around the world, and public interest in particle physics skyrocketed virtually overnight. But unlike the field’s newfound popularity, the Higgs boson and the incredible machine that found it didn’t come out of nowhere. The road to this moment in particle physics has been a long one, and in Collider: The Search for the World’s Smallest Particles, physicist Paul Halpern gives a quick and dirty rundown of how we got here.

An expert in the field of general relativity and a professor at the University of the Sciences in Philadelphia, Halpern is the author of twelve popular science books, including Faraway Worlds, What’s Science Ever Done For Us: What the Simpsons Can Teach Us About Physics, Robots, Life, and the Universe, The Great Beyond: Higher Dimensions, Parallel Universes and the Extraordinary Search for a Theory of Everything and Edge of the Universe: a Voyage to the Cosmic Horizon and Beyond.

For anyone who’s new to particle physics, Halpern’s Collider offers a mix of historical background and scientific explanation that doesn’t get too bogged down in details, but rather serves as a kind of who’s who and what’s what reference guide to the field. Unfortunately, Halpern advertises Collider as the story of the LHC, not the history of particle physics. In truth, the machine barely comes up in the first two thirds of it. So if you’re looking for a book about the LHC, look elsewhere. If you’re interested in a history lesson, then let’s continue.

To prepare us for this whirlwind tour of particle physics, Halpern compares us to particles in an accelerator. Warning: this foreshadows Halpern’s unbridled use of analogies (more on that later). “…Before propelling ourselves into modern issues and techniques, we must first boost ourselves up to speed with a look at the history of elementary particles and the methods used to unravel their secrets,” he writes. “Like a ride through a high-energy accelerator, it is a fantastic journey indeed.”

Now, if you want to indulge Halpern’s delusion that his book is about the LHC, then be sure to read the book’s preface, prologue, and introduction before jumping in at chapter 1. There’s more about the LHC in these disjointed supplementary sections than in most of the rest of the book.

In the first, Halpern details the LHC’s shaky start in 2008. Like its U.S. predecessor, the Tevatron at Fermilab, the LHC uses superconducting electromagnets to guide its particles around its 17-mile ring until they’re fast enough to smash together. Superconducting magnets are useful because at extremely low temperatures, they conduct electricity with zero resistance and produce very strong magnetic fields that can keep fast-moving, energetic particles under control. If, however, their temperature rises above a critical point, they resume normal conductivity in a violent burst of energy called a quench. The LHC experienced a catastrophic quench soon after it began running and had to shut down for more than a year.

In the prologue that follows, Halpern gives a first-person account of his own trip to CERN and tour of the LHC, conveying the immensity of the machine and the beauty of the surrounding French countryside.

Finally in the introduction, Halpern lets out his inner theorist and muses on physicists’ desire to understand the complete set of particles and forces in our universe and how by creating tiny microcosms of Big Bang-like conditions, the LHC could aid in this endeavor.

Then we jump back in time. First stop: ancient Greece, where philosophers debated what matter was made of. Was it the four elements or tiny pebble-like building blocks? Fast forward to the 1600s, when chemist Robert Boyle coined the term “element.” Up next, the 18^th century to introduce chemist John Dalton and the concept of an “atom.” Moving right along, we learn about further work on atomic theory by Thomas Thomson and Dmitry Mendeleyev in the 1800s. All the while, there was Newton playing around with gravity, Ben Franklin discovering electric charge, Joseph Priestley taking a stab at explaining the electrostatic force and then Charles-Augustin de Coulomb proving him right!

I won’t continue, but you get the picture. Halpern covers a lot of ground in just the first two chapters.

Eventually, we get to the early 1900s. By that time, thanks to J. J. Thomson and Ernest Rutherford, physicists knew that atoms were composed of electrons and nuclei but decided that in order to truly understand matter, they would need to start breaking nuclei apart. Thus began the long tradition of particle physicists using electromagnetic fields to accelerate charged particles and smash them into fixed targets or each other in order to see the universe in finer and finer detail.

Halpern gives us the evolution of these machines, called accelerators, starting with Van de Graaff generators, Cockroft-Waltons, and cyclotrons that use giant magnets to guide accelerating particles in concentric circles. Eventually we get to synchrotrons, like the LHC, that use rings of magnets to guide particles in fixed circles.

By mid-century (nearly halfway through the book), the plot thickens, and Collider starts to read more like a story, rather than a series of dates and names.

For decades, there’s been competition between American and European particle physicists, even though there’s also been great collaboration. Europeans dominated the field in its pre-accelerator days, but by the mid-1900s, the two particle physics hubs were in a back-and-forth over who had the more powerful machine.

Particle physicists measure energy in electron volts, or eV. For reference, a molecule at room temperature has less than 0.1 eV. The U.S. built the 3.3 billion eV(per particle) Cosmotron at Brookhaven National Laboratory in 1953 and the 6.6 billion eV Bevatron at Berkeley in 1954. CERN built the 28 billion eV Proton Synchrotron in 1959, then Fermilab built the 400 billion eV Main Ring, then CERN built the 480 billion eV Super Proton Synchrotron, then Fermilab built the 1 trillion eV (and later 2 trillion eV) Tevatron in 1983. Halpern lingers for a bit on the Tevatron, as it was the world’s most powerful collider for the 28 years prior to the LHC.

But before getting to the LHC, Halpern spends a whole chapter on the fascinating and tragic story of the Superconducting Super Collider (SSC), or Desertron. This 54-mile, 20 trillion eV synchrotron was under construction in Texas when the U.S. government slashed the project from its budget in 1993. Halpern takes an interesting look at how politics doomed the SSC. Unlike CERN, which decided to build the LHC in an existing tunnel, the U.S. government decided to start from scratch. If it had instead allowed Fermilab to use existing infrastructure for the collider, Halpern suggests, perhaps the SSC would have pulled through and the Higgs discovery would have happened on domestic soil.

To complete Halpern’s analogy from the beginning of the book, when we finally get to the construction of the LHC, we, the particles, should finally collide with awe-inspiring information about the world’s most famous science experiment. Instead, Halpern keeps up the swift pace of the rest of the book and tells us about the machine in a single chapter before moving on to what physicists hope to use it for.

It’s too bad, because he tempts us with statements like “Researchers realized that two extreme conditions would need to be maintained to make the LHC a success. These requirements would bring some of the most hostile aspects of outer space down to Earth,” then allows only two paragraphs of explanation before moving on. Those “hostile aspects,” by the way, are near-vacuum emptiness and temperatures below 450 degrees Fahrenheit.

Or he’ll bring up that scientists had to account for the moon’s gravitational effects on the Earth’s crust in constructing the ring, then jump to something else a few sentences later. As it turns out, the LHC’s length fluctuates about 1/25 of an inch due to these “lunar influences.”

Such mind-blowing details beg the question, why not condense the field’s history and instead devote most of the book to this incredible machine, which he claims to do anyway? And it’s a shame that we don’t get first-hand accounts of the LHC’s construction. Unlike Cockroft, Walton and Van de Graaff, the masterminds behind the LHC are still around to tell their stories.

Perhaps because Halpern himself is a theorist, he instead moves right along into what physicists hope the LHC will add to our understanding of the universe. Could it help reveal the identity of our universe’s dark matter by detecting so-called supersymmetric companion particles like neutralinos, charginos, gluinos, photinos, squarks and sleptons? Could it detect the extra dimensions predicted by string theory?

First published in 2009 and then updated in 2010, Collider preceded the Higgs discovery and therefore discusses it as one of these hoped-for findings. Since the book is mostly about what came before the LHC, this ends up being only a minor problem.

At the end of the book, Halpern muses on the future of particle physics and the next big machine, but first, he devotes the second-to-last chapter entirely to the bogus accusations that the LHC could create mini black holes that would destroy the planet. In short, it could, hypothetically, create mini black holes, but they wouldn’t destroy the planet.

One more thing — if you decide to pick up Collider, I have to warn you about Halpern’s use of analogies. He throws them around like beaded necklaces at Mardi Gras. Some of them are useful, like when he writes that the LHC can create Big Bang-like conditions but can’t re-create the Big Bang itself because doing so would be like “pouring a thimbleful of water on a smidgen of sand to test beach erosion.” Others are simply forced and unnecessary, and some are downright bad. In trying to explain an accordion-like configuration of our four dimensional existence in a theorized 11 dimensional world, he writes: “It would be the same as standing at the end of a serpentine line winding around a zigzag chain-link fence and then having someone lift a chain that allows you suddenly to be right next to the person formerly well ahead of you.” Good luck picturing that!

Despite Halpern’s false advertising and forced analogies, Collider is an interesting and informative read. Should I ever need to look up a tidbit of particle physics history, I know where to look. I won’t get much detail, but I’ll get the gist.