The Particle at the End of the Universe: How the Hunt for the Higgs Boson Leads Us to the Edge of a New World (39 page)

Spinoffs

Research in particle physics often does lead to very tangible benefits. Those benefits usually take the form of spinoffs—new technologies that were developed to help meet the challenges posed by the experimental effort itself, rather than direct applications of finding new particles.

The most obvious example is the World Wide Web. Tim Berners-Lee, working at CERN, pioneered the Web when he was trying to develop ways to make it easier for particle physicists to share information. Now it’s hard to imagine our world without it. Nobody ever suggested funding CERN because some day they would invent the WWW; it’s just a matter of putting smart people into an intense environment with daunting technological challenges, and reaping the benefits from what comes out.

There are many other similar examples. The need for uniquely powerful magnets in particle accelerators has led to noticeable advances in superconducting technology. The ability to manipulate particles has had applications in medicine, food sterilization and testing, and other areas of science such as chemistry and biology. The durable and high-precision detectors that appear in particle experiments have found uses in medicine, radiation testing, and security. The incredible demands on computing power and information transfer between particle physicists have led to advances in computer technology. The list is very long, but the lesson is very clear: Money spent on searching for esoteric particles doesn’t just slide down the drain.

It’s hard to quantify exactly how efficient it is to invest in fundamental research. Studies by economist Edwin Mansfield suggested that, for society as a whole, it is a wise investment indeed. Mansfield argues that public spending on basic science yields an average return of 28 percent, which almost anyone would be thrilled to get out of their investment portfolio. A number like that is suggestive at best, because the details depend greatly on what industries are studied and what counts as “basic science.” But it reinforces the anecdotal impression that, at the cutting edge of science, even the most nonapplied research yields impressive dividends.

The most important spinoff of basic research isn’t technological at all—it’s the inspiration that science provides for people of all ages. Who knows when a certain child is going to hear a news story about the Higgs boson, become intrigued by science, start studying, and end up as a world-class doctor or engineer? When society puts some small fraction of its wealth into asking and answering big questions, it reminds us all of the curiosity we have about our universe. And that leads to all sorts of good places.

The future of particle physics

Weinberg’s ornery congressman aside, most people are willing to admit that learning the laws of nature is a worthwhile project. It’s reasonable to ask, however, precisely how much we think it’s worth. The fate of the Superconducting Super Collider weighs heavily on anyone who contemplates the future of particle physics. We live in an era in which money is tight, and expensive projects need to justify themselves. The LHC is an amazing accomplishment and will hopefully hum along for many years to come, but at some point we will have learned everything it has to teach us. What then?

The problem is that, while the overwhelming majority of worthwhile scientific projects are much less expensive than high-energy particle accelerators, there are certain questions that can’t be addressed without such a machine. The LHC cost roughly $9 billion, and it has given us the Higgs boson and, hopefully, will give us much more in the future. If we were limited to spending only $4.5 billion on that project, we wouldn’t have discovered half a Higgs boson or taken twice as long; we simply would have found nothing. Making new particles requires high energies and substantial luminosities, which require a large amount of precision equipment and expertise, which cost money. Hanging over all the jubilation for the wonderful performance of the LHC is the very real possibility that it may be the last high-energy accelerator built in our lifetimes.

There is no shortage of plans for possible next steps forward, if the money can be found. The LHC itself could be upgraded to higher energies, although that seems like a stopgap solution. More attention has been focused on the possibility of a new linear collider (in a straight line, rather than a ring), which would collide electrons and positrons. One proposal has been dubbed the International Linear Collider (ILC), which would be more than twenty miles long and reach energies of either 500 GeV or 1 TeV.

That sounds like less energy than the LHC, which might seem like a step backward, but electron-positron colliders work in a different mode from that of hadron colliders. Rather than throwing as much energy as possible into collisions and seeing what comes out, electron-positron machines are ideal for precision work, which can be achieved by aiming at precisely the energy required to produce a specific new particle. Now that we believe the Higgs is at 125 GeV, it provides a tempting target for physics at a linear collider.

Cost estimates for the ILC range anywhere from $7 billion to $25 billion, and possible sites have been explored in Europe, the United States, and Japan. The project would clearly require major international collaboration and necessitate as much political acumen as experimental physics know-how. An alternative proposal, the Compact Linear Collider (CLIC), has been developed at CERN. It would actually be shorter but reach higher energies through the use of innovative (and therefore riskier) technologies. In 2012, studies for the two competing projects were brought together under a single umbrella. The new leader of the combined effort will be Lyn Evans, who didn’t get to enjoy much of a retirement after stepping down from heading the LHC team. It will be Evans’s job to decide on the most promising technology for moving forward, as well as to juggle the competing interests of different countries who would love to host a new collider (but don’t want to pay for it).

One of the persistent themes you hear when talking to anyone who has been involved with the LHC is the inspirational success of its international collaboration. Scientists and technicians of many different nationalities and ages and backgrounds have come together to build something larger than themselves. If our larger society can summon the willpower to put substantial resources into new facilities, the future of particle physics is bright. But for that to happen, scientists have to convey the interest and importance of what they do. We can’t sell particle physics on the basis that it might someday cure Alzheimer’s or lead to portable teleportation devices. We have to tell the truth: We want to discover how nature works. How much that’s worth is for the human race as a whole to decide.

Wonder

Interviewing my fellow physicists for this book, I was struck by how many were fascinated by the arts before they eventually turned to science. Fabiola Gianotti, Joe Incandela, and Sau Lan Wu all studied art or music when they were young; David Kaplan was a film major.

It’s not a coincidence. Even though our quest to understand how nature works often leads to practical applications, that’s rarely what gets people interested in the first place. Passion for science derives from an aesthetic sensibility, not a practical one. We discover something new about the world, and that lets us better appreciate its beauty. On the surface, the weak interactions are a mess: The force-carrying bosons have different masses and charges, and different interaction strengths for different particles. Then we dig deeper, and an elegant mechanism emerges: a broken symmetry, hidden from our view by a field pervading space. It’s like being able to read poetry in the original language, instead of being stuck with mediocre translations.

I was recently helping out with a TV show that was trying to explain the Higgs boson. When you do TV, words never suffice; you need compelling images. If you’re trying to explain subatomic phenomena, the only way to get compelling images is to reach for an analogy. So here’s what I came up with: Imagine little robots scooting about on the floor of a vacuum chamber. Each robot is equipped with a sail, but the sails come in all different sizes, from fairly large to quite small. We first film the robots when the chamber has been evacuated; they all move at the same speed, since the sails are completely irrelevant when there’s no air for them to feel. But then we let the atmosphere into the chamber and film them moving again. Now the robots with tiny sails still move quickly, while those with large sails are much more sluggish. Hopefully the analogy is clear. The robots are particles, and the sails are their couplings to the Higgs field, which is represented by the air. In a vacuum, where there is no air, the robots are all symmetric and move at the same speed. Filling the chamber with air breaks the symmetry, just like the Higgs field does. You could even draw an analogy between sound waves in the air and the Higgs particle.

Since I’m a theoretically minded person myself, nobody wants to put me in charge of robots, so I consulted with some of my colleagues at Caltech in engineering and aeronautics. When I explained what we wanted to do, the response was universal: “I have no idea what the Higgs boson is, or whether that’s a good analogy, but it sounds
awesome
.”

At heart, science is the quest for awesome—the literal awe that you feel when you understand something profound for the first time. It’s a feeling we are all born with, although it often gets lost as we grow up and more mundane concerns take over our lives. When a big event happens, like the discovery of the Higgs boson at the LHC, that childlike curiosity in all of us comes to the fore once again. It took thousands of people to build the LHC and its experiments and to analyze the data that led to that discovery, but the accomplishment belongs to everyone who is interested in the universe.

Mohammed Yahia writes
Nature
magazine’s
House of Wisdom
blog, dedicated to science in the Middle East. After the July 4 seminars announcing the discovery of the Higgs, he celebrated the universality of the scientific impulse.

As people across the Arab world are all dealing with their politics, revolutions, human rights issues and uprisings, science speaks to all of us equally and we become one. The only two human endeavours that are cross-boundary at this massive scale are art and science.

On July 4, 2012, only hours after the seminars that announced the discovery of the Higgs boson to the waiting world, Lyn Evans was asked what he hoped young people would take from the news. His response was immediate: “Inspiration. These big flagship projects have to be inspirational. When we were young there were lots of things going on—putting a man on the moon. Exciting young people in science is essential.” They’ve succeeded.

Meaning and truth

Particle physics can trace its roots back to the atomists of ancient Greece and Rome. Philosophers such as Leucippus, Democritus, Epicurus, and Lucretius developed an understanding of the natural world based on the idea that matter and energy represented different arrangements of a small number of fundamental atoms. They were not scientists in the modern sense of the word, but some of their insights fit quite well with how we think about the universe today.

The ancient world didn’t recognize the strict boundaries we have erected to separate academic disciplines in the contemporary university, so as philosophers they were as interested in ethics and the meaning of life as they were in material reality. As with their understanding of atoms, not all of their conclusions hold up from our perspective today, but many of their ideas still remain relevant. They attempted to follow the logical consequences of their atomic view of the world. If reality is simply the interplay of atoms, where are we to find purpose and meaning? Epicurus, in particular, responded to this challenge by locating value in life as we actually live it here on earth, encouraging his followers to be tranquil in the face of death, to value friendship highly, and to seek pleasure in moderation.

Science is ultimately a descriptive enterprise, not a prescriptive one. It tells us what happens in the world, not what should happen or how to judge what happens. Knowing the mass of the Higgs boson doesn’t make us better people, or help us decide which charity to support. Nevertheless, the practice of science has crucial lessons for how we live our lives.

The first lesson is that we are part of the universe. Everything in the human body is successfully described by the Standard Model of particle physics. The heavier elements that are so crucial to our biochemistry were formed by nuclear fusion inside stars, leading to Carl Sagan’s dictum, “We are star stuff.” Knowing that our atoms obey the Standard Model isn’t very helpful when it comes to real-world problems of politics, psychology, economics, or romance; but any ideas you have along those lines must at least conform to what we know about the behavior of elementary particles.

We are part of the universe that has developed a remarkable ability: We can hold an image of the world in our minds. We are matter contemplating itself. How is that possible? Particle physics doesn’t give us the answer, but it’s a basic ingredient in the larger story in which the answer arises. With the discovery of the Higgs boson, our understanding of the physics underlying everyday reality is complete. There is plenty of room for new particles and forces, but only ones that interact so weakly or briefly with ordinary matter that we can’t perceive them without billions of dollars’ worth of apparatus. This is a towering achievement in human intellectual history.

The other lesson of science is that nature doesn’t let us fool ourselves. Science proceeds by making guesses, which it dignifies by calling them “hypotheses,” and then testing those guesses against the data. The process might take decades or longer—and what qualifies as “the best explanation for the data” is a notoriously knotty problem—but ultimately, the experiments have the final say. It doesn’t matter how beautiful your idea is, or how many awards you’ve won, or how many IQ points you have; if your theory contradicts the data, it’s wrong.