With the Large Hadron Collider set to start up in November, a new book takes you inside the world's largest and most powerful particle accelerator.

Paul Halpern has a Ph.D. in theoretical physics and is a professor at the University of the Sciences in Philadelphia. He is the author of 13 popular science books, including Cosmic Wormholes and the Cyclical Serpent. Read an exclusive excerpt from his latest book, Collider.

Physicist Paul Halpern explores the past, present and intriguing future of high-energy particle physics in Collider. He explains what all the hubbub surrounding the LHC is about and why physicists are pretty much beside themselves with anticipation.

Wired.com spoke with Halpern about what the LHC may find and how the United States failed in its quest for its own giant collider.

Wired.com: We hear a lot about the Higgs boson and whether it will be found in the U.S. by Fermilab's Tevaton or at CERN (European Organization for Nuclear Research) by the LHC. What’s so great about the Higgs?

Paul Halpern: In the 1970s the Standard Model was developed, which is a way of uniting electromagnetism with the weak force. It predicts certain types of particles: the W and Z bosons as the carriers of the weak force, and the Higgs boson as a mechanism for explaining why the W and Z bosons are so much heavier than the photons, which are massless. The Higgs boson is the only known way to explain the great disparity between masses, and theoretical physics works best when you assume that all particles have equal mass.

Fields theory imagines that at some fundamental level, at highest energies all particles are essentially interacting points which have zero mass, and that somehow something created a disparity, and that was the Higgs field. The Higgs field is just something that fills up all of space, and it has a free parameter kind of like a roulette wheel that can spin in any direction.

Somehow when the temperature of the universe cooled beyond a certain amount there was a phase transition, and the Higgs field became locked in one direction, shared by the entire Higgs field across space in lockstep. Once the Higgs field locked into that phase, first of all that set the lowest energy of the universe, and secondly that energy was translated into a

mass which was given to certain particles. These were particles that interacted with the Higgs field, and these included the W and Z bosons but also the quarks and leptons that make up matter. These acquired mass, and it explains why everything around us except for photons has mass.

And just like ice freezing into patterns, the universe froze into certain patterns, and these patterns meant the acquisition of mass by certain particles. The Higgs that scientists are looking for is kind of a remnant of the original Higgs field. It's kind of a leftover, a relic.

Wired.com: Was it worth building an $8 billion collider to find the Higgs boson?

Halpern: Well, that’s only one of the uses for the collider. Another use is to look for what are called the minimally supersymmetric Standard Model particles, which is a fancy way of saying particles that are expected to be slightly higher mass than known particles but that occupy a kind of mirror world. So in our world, photons, which are a type of boson, carry force, W and Z particles carry force, and things called gravitons and gluons also carry force. And quarks and leptons are the building blocks of matter. But there’s no reason to assume that this division always existed.

Perhaps early on in the universe, there was one type of particle which was kind of a combination of matter and force carrying particles. That would mean there must be companions of quarks and leptons which are like them but with certain opposite properties... We’re looking for the lowest energy ones because it’s predicted that some of them will have masses that might be able to be detected in colliders.

No one’s hoping to find all the supersymmetric companions, but if we could just find the lowest energy ones, then people who believe in supersymmetry will know that they’re on the right track. But so far there’s absolutely no evidence for supersymmetry and theorists have been talking about it since the 1970s. Supersymmetry plays a role in what’s called string theory too. And if supersymmetry is not true, than that rules out certain types of string theory.

Wired.com: What else could the LHC find?

Halpern: The other reason for looking for these supersymmetric companions is to try to find the elusive particles that make up what's called dark matter. Astronomers know that much of the universe is missing. In fact, if you add up all the energy and mass in the universe, 95 percent is invisible. Only 5 percent is known visible matter including everything around us, atoms and so forth, and 95 percent is either dark energy or dark matter. Dark energy meaning repulsive type of energy which is pushing the universe apart and dark matter meaning a type of matter which is exerting a gravitational pull on galaxies but we don't see it.

The reason astronomers believe in dark matter is because if you just take visible matter, then the stars on the edges of galaxies ought to be moving a lot slower than they are. Another piece of evidence is that galaxies ought to be less tightly clustered than they are. So for example, if you look at our galaxy and the neighboring galaxies, and you predict how much pull they should exert on each other, there's something missing. There's some missing glue that's holding the galaxies together into clusters.

Wired.com: How big a blow was it to American science to lose the Superconducting Super Collider?

Halpern: I know a professor who left a long-standing tenured university position, where he was a full professor and highly respected, to get a job at the SSC. And then after resigning from his job which he had his whole life, the SSC was canceled and he couldn't go back to his original position. He had to take a job at a small college. And I'm sure there are many stories like that. There are many people whose careers were completely severed because of the SSC, from the support staff all the way up to the professors plus students who were planning to use that material for dissertations and things like that.

It had a huge impact first of all on the perception of the United States I think. In recent years the perception that the United States is on the leading edge of science has waned, especially in high-energy physics. So Europe has renewed vigor, renewed centrality in science. And that, coupled with the unfortunate disasters and setbacks in NASA, lent a double blow to the perception of American science.

When I went over to CERN to interview scientists, I met someone who was involved with the SSC but then came over to CERN. He was very cynical about American science and said a big difference between Europe and the United States is that in the United States budgets are year to year, and in recent years there's been no long-term commitment so there's no kind of budget which can be planned 10 years in advance. Whereas for CERN, European governments commit a certain amount of money every year and then the CERN board decides what that money is used for. So the CERN board can plan 10 years in advance. CERN is already planning upgrades to the LHC and so forth. Whereas with the SSC everything was done year to year, and whether or not it would get funding or how much funding, that was up for grabs every single year.

Wired.com: Is the LHC the last super collider we're going to see?

Halpern: They're talking about a linear collider, which is the ILC, International Linear Collider. That's in the early planning stages and that wouldn't be a ruing that would involve two linear accelerators colliding particles with each other which would require a lot of land. But the advantage of the linear colliders is that they can narrow down the energies and thus narrow down the masses more precisely.

With the LHC they can't really enlarge the ring or build a new ring. There's just no room, they're up against the mountains. So one side is the mountains, the other side is Geneva. So unless they can get rid of the mountains or get rid of Geneva there's no place to enlarge the ring. But what they can do is replace the magnets. So they're planning to replace the magnets sometime in the next decade and upgrade it and that will be the super LHC. And the reason that will improve things is because with stronger magnets they can improve the luminosity and luminosity means improving the chances of collision.

__Wired.com: __Have we ceded the lead in high-energy physics for good?

Halpern: Never say never. It could be the case that in an era in which the American budget deficit is reduced, or perhaps we even have a surplus again someday, somewhere down the line American scientists will start to push for an increase in funds toward high-energy physics. But right now the clout of high-energy physics is fairly low because of the shift towards Europe.

Unfortunately it means a lot for the American educational system. We're going to have at least a generation of students in the United States who wont be able to have much hands-on experience with particle physics. And if they want to become a high-energy physicist, they know they're going to have to spend time in Europe or else just be computer analysts. If they want equipment experience they'll have to go to Europe or else they can just get data channeled from Europe to the United States and just analyze the data and do everything remotely.

So I kind of fear for the future of high-energy physics because traditionally experimentalists had a lot of hands-on experience with detectors and could produce the hardware. But then they would also get experience with the software and with the computer programming and analysis. However, nowadays it's harder and harder for people to get detector experience because once a detector is sealed up, people can't really interact with it. Then you have people who are in other countries analyzing the data who have very little chance of interacting with the equipment.

So what would happen is, if let's say there needs to be a new generation of detectors or a new gen of accelerators, that there might be very little experience among the next generation of students. I think it's gonna be a real problem because you need well-trained people in order to troubleshoot and to suggest new devices and so forth; now perhaps people will be able to do it from a theoretical knowledge from studying the older systems and so forth but I think hands-on experience has been really critical to particle physics so far. So for instance, the people who work in the LHC for the most part, the leaders there are people who worked with much smaller detectors at Fermilab and at the SPS and so forth and know exactly how everything fits together.

__Wired.com: __What would it mean to the U.S. if the Tevatron were to find the Higgs boson before the LHC?

Halpern: I think it would give a new boost to American high-energy physics. But it could be a short-lived boost, because then the question would be will we channel money into some kind of extension to Fermilab or a new accelerator, or will the next discoveries be in Europe?

But I think what's going to happen ultimately is that everything's going to be international. I think that's the direction that big science is going, that no one country can afford projects. Countries don't want to invest in national projects, they want to invest in international projects. That was part of the problem with the SSC. It was sort of an American project, but we wanted it to be international and we wanted to get other countries to invest in us. Whereas the ILC is genuinely international in that the site hasn't been chosen yet and it could be any country, and countries are expected to donate; everybody who's involved is expected to make a donation so it's more equal.

Image: CERN

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