Collision course.

The Geneva research center known as CERN, or the European Organization for Nuclear Research, is the world's largest physics laboratory. Its focus is studying the basic components of matter and how the universe works. Financed by 20 European countries, its annual budget is US$800 million. CERN's largest project to date is a particle accelerator. Based on the collaboration of more then 6,000 scientists around the world, it will cost more than $3 billion and will be finished in 2007. LATIN TRADE Spanish Editor Andres F. Velazquez talked with John Ellis, a CEBN senior physicist and advisor to the lab's general director, about the center's goals and what part Latin America's science community can play.

Why is CERN's work so important?

Antimatter, for instance, was discovered a few decades ago and is used to make medical diagnoses, like chemotherapy. Every physics discovery has some application to everyday life. Of course, there can be a long delay between the discovery of a concept in physics and its practical application.

What are you working on now?

The basic thing we are trying to understand is why some particles have weight and some don't. Centuries ago, Newton said that the weight of an object is proportional to its mass. But neither Einstein nor Newton explained the origin of mass. We have a theory that explains where mass comes from. It involves some new particles. One of the main objectives of the accelerator [which speeds up particles for their study] we are building is to find Higgs particles. In order to produce them we have to smash protons at high speeds and thus make new, very heavy particles.

What could be the practical use of these kinds of discoveries?

We won't see any immediate applications. But all modern technology is based on discoveries made decades ago that, at the time, seemed irrelevant.

What about this accelerator that cost $3 billion?

That is called the LHC [Large Hadron Collider]. The tunnel is 100 meters below the earth. The diameter of the tunnel is four meters. The two biggest of them cost $400 million each. Many hospitals use small accelerators to create nuclear isotopes for medical diagnostics. There are now 10,000 accelerators in the world. We are building the world's biggest. It consists of a circular tunnel 27 kilometers in length and has thousands of magnets used to make the particles spin and increase in speed so that they have an ever-increasing amount of energy. The magnets are kept at temperatures nearly as cold as the universe itself. The universe is -273 degrees centigrade. Our accelerator operates at -271 degrees centigrade.

Do Latin American governments or scientists take part in CERN activities?

The LHC accelerator makes particles collide, but then you need machines capable of observing the collisions in order to see the particles that are produced. A network of scientists around the world is building these detectors. The two largest of them being built involve 2,000 scientists and engineers each from between 30 and 40 countries. The European countries and CERN members build the basic infrastructure. Then other countries join in to do the experiments. Then we have observing countries, like the United Sates, Russia, Japan, Turkey, Israel and India. After that we have international accords with 35 countries around the world. These are Taiwan, China, Pakistan, Iran, South Africa, Australia, Canada, New Zealand, Brazil, Mexico and Argentina. Colombia and Chile also have cooperative agreements with CERN.

How does CERN benefit from the work of Latin American scientists?

We gain if we have more minds helping us. There is a lot of sophisticated, intellectual work that needs to be done. The more people we can get involved the better, no matter where they are from. We might be farther ahead in terms of particle physics, but there are many aspects of electrical engineering in which Latin Americans are the experts. For example, in Chile there are some physicists who want to take part in our experiments. These engineers are experts in electrical systems and frequency interference in electrical systems. As you might imagine, this is a big problem for our detectors. Each detector has 10 million elements, and each one has its own electrical circuit.