"But enough about High-Energy Physics.
Let's talk about you.
What do you think about High-Energy Physics?"

by Judy Jackson

As U.S. high-energy physicists chart the course for their future, they must first reach agreement among themselves on a road map to the revolutionary new physics that nearly all agree lies ahead. Although converging on a plan within their own ranks is no easy task, it is child’s play compared to the next step: persuading the rest of the world that the scientific promise of twenty-first century particle physics is worth the cost.

Particle physics moves forward on technology that creates ever-higher energy; and, as the energy gets higher, the cost goes up. The tolls are high on the road to the future of particle physics. To turn their map into reality, therefore, particle physicists must successfully make the case for their science to many audiences, including federal funding agencies and Members of Congress. Moreover, they must do so in a world profoundly changed, since September’s terrorist attacks, from the one they have known.

One key constituency that particle physicists must address as they plan for the future is not in Washington but much closer to home: their colleagues down the hall. Although high-energy physicists are sometimes accused of forgetting it, there are other fields of physics. Besides particle physics, university physics departments comprise a dynamic mix of experimentalists and theorists in fields from astrophysics to solid-state physics to optics. What are their views on high-energy physics? What do they think of its prospects? A recent visit to the physics department at the University of Michigan provided some eye-opening answers.

With 50 Fermilab experimenters, the University of Michigan in Ann Arbor fields the third-largest user group at the laboratory. Michigan physicists collaborate on both CDF and DZero, Fermilab’s big collider experiments, and on MiniBooNE. Besides its depth in particle physics, the Michigan physics department has strong groups in solid state and condensed matter physics; astrophysics and atomic, molecular and optical physics. Last September, just as the new academic year was getting under way, four Michigan physicists not of the particle persuasion agreed to share their perspectives on high-energy physics. They didn’t speak for the entire department, just for themselves. And Michigan is only one university—albeit an eminent one—among the nation’s hundreds of research institutions. Obviously, the opinions of four scientists don’t constitute any sort of physics community survey. Nevertheless, at a moment when U.S. particle physicists are preparing to come forward with a plan for the future, their views are enlightening.

Roy Clarke came to Michigan 20 years ago as part of a “first wave” of condensed-matter physicists, with a charter to build a strong solid-state physics effort in Ann Arbor. Today, he works on an experiment using intense x-rays from Argonne National Laboratory’s Advanced Photon Source. Clarke, making a point that all four scientists mentioned, contrasted his 20-person experiment at the APS with huge particle physics experiments.

“In solid-state physics, the single investigator grant is the norm—a couple of post-docs and a principal investigator.”

Roberto Merlin, a solid-state experimentalist who arrived in Ann Arbor at about the same time as Clarke, further emphasized this difference.

“I could not work in high-energy physics,” Merlin said. “I am dismayed by the pack mentality. It is very different when I am an independent contractor, where I can do what I want to do. I can argue the science with my peers, as opposed to particle physics, where there is a mere handful of experiments and the options are limited.”

Theorist Len Sander is a statistical physicist who works on diffusion-limited aggregation, which he described as the fundamental processes of condensed matter physics regarded as collective phenomena.

“More is different,” Sander said. “The fundamental phenomena in particle physics are simple. But ‘fundamental’ is in the eye of the beholder. Collective phenomena are things where new phenomena arise when many particles are involved. It involves a different kind of reasoning and a different view of the world.”

And in Sander’s view of the world, the collective phenomenon of big particle physics experiments represents an extreme.

“They are about as far as you can go in that direction,” Sander said. “It is not easy to distinguish one researcher from another in the big particle physics collaborations.”

All the Michigan scientists pointed to the synergy of particle physics with other fields of physics.

“This department has embraced many areas,” said Physics Department Chair Ctirad Uher. “We celebrate success in any area of physics. Interactions are always helpful.”

All four gave credit to the critical contributions particle physics has made to their fields, noting as well that “it goes both ways.”

Clarke cited the importance for particle physics of laser-induced electron emission and other techniques from solid-state physics, but emphasized that the connection goes far beyond technology.

“There is much common ground between particle physics and condensed matter physics at quite a deep level,” Clarke said. “Field theories from condensed matter physics have had a significant impact on theoretical structures of particle physics.”

But when it comes to connections among scientists, some Michigan physicists saw problems.

“The high-energy physics community is still not connected,” Sanders said. “Although the younger people, the younger experimenters seem to be a different breed; they talk to colleagues in other fields of physics. You can relate to them as scientists. But the leadership is still the same.”

Merlin agreed.

“Some younger high-energy people do come to condensed-matter seminars,” he said. “There is a big difference between the young and the older generation.”

When asked about their high-energy colleagues’ hopes for the future, including the possibility of building a future accelerator, the Michigan physicists’ message could not have been clearer. And, in case anyone was wondering, no, they have not forgotten the Superconducting Super Collider. Sander put it most bluntly.

“I remember the SSC,” Sander said. “You failed to attract the support of the rest of the physics community. There was a feeling of arrogance, of ‘we don’t need you.’ You should have brought the condensed matter people into the plan.

“I am unhappy with the aggressiveness and the hyperbole of the high-energy physicists who were committed to their lobbying effort. If the SSC was not funded, the message went, it would be the end of particle physics in the U.S. Yet, today, particle physics seems just fine. When the dust settled, we learned that even other particle physicists had serious reservations that they kept to themselves.”

As for how to do things differently this time, all four Michigan physicists had the same advice: Talk to your colleagues about the science you want to do.

“Once you start talking about a few billions,” Merlin said, “you would be wise to spend time talking to the rest of the field. It should be properly done, maybe through the National Academy of Sciences. It is unwise to turn off your fellow physicists.”

It’s not that they don’t support high-energy physics; they do. Clarke decried the idea that support for one field of physics comes at the expense of others.

“In high-energy physics, as in every field,” Clarke said, “we need to look at the scale and the science of a project and compare it with other projects that are being promoted. It is not true that funding that goes to one branch of science gets taken away from another. Internal sniping has never done any one any good, and it never will. Physicists spend too much time in their own labs and not enough time talking to other people.”

Uher concurred.

“As long as funding goes to science,” he said, “that’s good.

But they do want to understand the science. The words of the Michigan department chair are likely to resonate for particle physicists in university departments and laboratories far beyond Ann Arbor.

“When the plan for the future of high-energy physics goes out to the general population,” Uher said, “it should have community input. First the high-energy physicists should unite among themselves and come up with the right project. Then they should sell it to the rest of the science community. If the fundamental science is important, the scientific community will support it. Particle physicists have to articulate the project’s benefits, to show how much it will advance science. Their task will be to excite intellectually their scientific colleagues. Without that, they will be dead in the water.”