Tevatron: how, what and why

In the Tevatron, protons and their antimatter equivalents, antiprotons, are accelerated at high energies in opposite directions around a three-and-a-half-mile loop. Scientists - including Wyatt - have built two large detectors, D-Zero and CDF, where the particles collide. They hope the detectors will enable them to discover new elementary particles, even the elusive "higgs boson", about which particle physicists have long theorised, but searched for without success.

In the near term, they hope to generate thousands of top quarks - the most massive elementary particles so far discovered, yet about which little is known.

Of the 600 D-Zero collaborators, 200 or so work at Fermilab full time, with the majority of these posted there by collaborating universities. The remaining 400 are Fermilab commuters, coming to the experiment whenever they can. Over summer, about 100 of these will take up residence at Fermilab, swelling numbers by a half.

The other main experiment, CDF, is of a similar size, with numbers increasing by between 25 and 50 per cent over summer.

The Tevatron, which has been upgraded recently, began running in March, five months after the Large Electron Positron accelerator at Cern was shut down. It gets its name because it collides particles at an energy of 2 trillion electric volts (Tev).

The Large Hadron Collider, Cern's more powerful accelerator, will not be ready until 2005 at the earliest.