From the issue dated October 22, 1999
NOTES FROM ACADEME

On the Franco-Swiss Border, Cosmic Collisions – and Another Big Bang?

By PETER MONAGHAN

Geneva

If you're looking for particle physicists, this is the place.

At any given time, half of the world's specialists in that field are likely to be working at CERN, the European Laboratory for Particle Physics. It's the largest such facility in the world, drawing scientists from more than 500 universities and 80 nations. There are probably 7,000 to 8,000 physicists here, "but we don't know exactly," says Neil Calder, director of CERN's news-media service. "We'd have to employ 50 people just to keep track of who's coming in and out."

The physicists' task is simple to describe and complicated to perform: Using magnetic fields, they propel beams of subatomic particles around a 17-mile circular tunnel, or accelerator, at almost the speed of light. The beams are steered into collisions with one another, creating fireballs of energy from which new particles are formed. The process, which creates conditions similar to those that existed soon after the big bang, allows researchers to explore what matter is made of and what forces hold it together.

Large instruments, called detectors, allow the researchers to discern the presence of the subatomic particles created in the collider. However, the scientists here must take into account distortions of the tunnel's circularity caused by the moon's gravity, as well as the effects of passing trains, a couple of stray beer bottles, and snowmelt from nearby mountains.

Mr. Calder has plenty of such anecdotes as he guides a visiting journalist on a tour of CERN's 1,500-acre campus, which sits astride – and lies beneath – the Franco-Swiss border, at the foot of the Jura Mountains. A Scot long resident here, he has honed to a fine art the task of showing off CERN to visitors in an old Swiss military jeep. Chugging along, he points out sheep grazing in a paddock and shouts over the engine: "We have a farm with a shepherd and two flocks of sheep. Cheaper than mowing!"

In tunnels 110 yards below the animals, CERN physicists are re-creating conditions believed to have existed at the formation of the universe, some 15 billion years ago.

CERN, founded in 1954, stands for the Conseil Europeen pour la Recherche Nucleaire. Its 20 European member states spend $650-million a year to run it. The center is now a global undertaking, with North American scientists the most numerous since the United States terminated the Superconducting Supercollider project in Texas, in 1993. The U.S. government supports some of the center's costs.

Mr. Calder pulls up at the portal to one of four shafts that plunge deep into the earth. An elevator zooms down to the Large Electron Positron Collider – the 17-mile ring that is the world's largest accelerator. In a domed space that is as vast as a medieval European cathedral stands a structure of electronic equipment, 70 feet high. It is rigged like some mad scientist's haunt, with dozens of appended machines and booths for monitoring them, decked in tangled clusters of wiring.

At the center of it all is one of the accelerator's four detectors, an enormous instrument consisting of layers of equipment, inside which some 40 million collisions of particles take place each second. That will increase to 800 million per second in 2005 – with each collision producing 10 million pieces of information – when CERN's new accelerator comes on line. Called the Large Hadron Collider, it will use superconductivity at very low temperatures to achieve much more intense beams of particles and much faster and more productive collisions. Two experiments already being prepared involve 1,700 physicists each.

The goal is to answer basic questions in physics: What is the behavior of the basic forces of nature – gravity, the so-called strong and weak forces, and electromagnetism? How do the basic particles of matter – such as up quarks, down quarks, electrons, and electron neutrinos – behave?

Scientists are still searching for the Higgs boson, another subatomic particle that is believed to exist. It has been described as being more like a field, fog, or mist than a particle, and is thought to be the key to solving such fundamental puzzles as why some particles have more mass than others.

Mr. Calder makes sure that visiting journalists hear about those theories directly from prominent physicists. Among them is Paris Sphicas, a research physicist from the Massachusetts Institute of Technology, who has been here for three years. He launches into a potted summary of the history of particle physics, from Aristotle through Newton and on to the "Higgs mechanism." He speaks of scientists' hope of an ultimate, elegant unification of physics theory, a "theory of everything," adding, "This is of such importance that I don't know what words to use."

He speaks so clearly that it all makes perfect sense at the time, but this reporter, who was as resistant to the confusions of high-school physics as to the pedantry of Latin, is nonetheless relieved to know that CERN sells a handy comic book, The World of Particles, that explains it all in terms a smart 8-year-old could understand. Another option is the "CERN in 2 Minutes" guide on the organization's World-Wide Web site (http://www.cern.ch/).

The CERN campus resembles a small, scattered town on the Swiss landscape. Countless auberges and bar-restaurants have set up shop to serve the residents of the tidy villas that sit behind stone fences, setting them off from the apartment blocks that house migrant workers. Among them all are farms and forests. A few months ago, a researcher fetching her bicycle from a shed at CERN surprised a lynx, one of the few left in this part of Europe.

"People tend to come here just to work," Mr. Calder says, but many of their social needs are catered to as well. CERN has its own nursery schools, soccer and rugby teams, a lending library, rental accommodations, and many clubs, including one that helps wives from going stir-crazy in the largely male – and famously overworking – world of particle physics. The ski club sends 15 busloads of skiers into the mountains every Saturday and Sunday in the winter months.

With so many scientists doing such abstract work, letting one another know what's up has posed its own hurdles. A major leap forward came from work done in 1989 by Tim Berners-Lee, now at M.I.T. He invented a distributed-information system, based on hypertext, that by 1993 had developed into the Web.

Another communications task is to present the accomplishments of CERN, which depends on the governments of the 20 member nations for support. Any group that wishes to tour the site or visit an experiment can do so free, guided by a young physicist.

For the scientists and CERN's 2,500 mechanics, technicians, and administrative-staff members, being here affords the pleasures of both a rare work environment and a strikingly scenic lakeside city. Lake Geneva, fed by snowmelt from the Jura, figures centrally in one of the stories of CERN life that Mr. Calder can easily be coaxed to tell. The physicists, he says, have found that their calculations must factor in fluctuations in the lake's volume, because they affect the earth's crust and deform CERN's accelerator minutely.

In 1991, the particle beams in the circular accelerator were oddly off target. A scientist concluded that the moon's gravitational pull was warping the accelerator by tiny but significant amounts.

Two years ago, a French national rail strike provided the answer to another nagging question: What was causing a disturbance in the magnetic fields that propel the particle beams forward? The culprit was stray current from the colossal surges of electricity that propel the high-speed train known as the T.G.V. as it departs Geneva's railway station. The current rode through the accelerator before hopping back to the rails, and only the strike, which halted the train's running, made that clear.

And the beer bottles?

A couple of years ago, on New Year's Day, the accelerator's beam was repeatedly crashing. What was the obstruction in the beam pipe?

Using clever mathematics and physics calculations, operators figured out where to open the accelerator to look inside. They found the two empty bottles, forgotten by mechanics during their New Year's carousing.

Copyright © 1999 by The Chronicle of Higher Education