Illinois atom smasher ushers in new era of discovery for physicists

American physicists are poised for a comeback in the international physics ''ball game.'' Recent innings have gone to the Europeans. They have equipment - an especially powerful particle-smashing accelerator - that gave them the edge in the friendly but earnest competition to uncover the basic nature of matter.

But last Sunday, at the Fermi National Accelerator Laboratory (Fermilab) at Batavia, Ill., a redesigned accelerator exceeded the top energy of its original design. Protons, the positively charged particles that help make up the nucleus of an atom, sped around the machine's four-mile circumference with an energy of 512 billion electron volts (512 gigaelectron volts, or GeV). This represents 112 GeV more than the unit's old maximum energy. Soon the accelerator is expected to produce protons with 1,000 GeV, or 1 teravolt (TeV). Hence the machine's new name, the Tevatron.

Within another two to three years, the Tevatron should be smashing two opposing beams of 1-TeV protons together for a total interaction energy of 2 TeV. That's nearly four times the energy available in the colliding beams at the European Center for Nuclear Research (CERN) at Geneva that has garnered the recent prizes.

At that energy, says Fermilab director Leon M. Lederman jubilantly, physicists will be able to explore matter in an energy range ''beyond the area where theorists can safely project their theories.'' It would, in fact, be the start of a new physics ''ball game.''

Physics has entered a new era of discovery. American physicists want very much to be among the explorers, using their own equipment in their own laboratories, as well as working as visitors abroad.

This year CERN teams (which included United States physicists) found new particles (the W and Z particles) that show the unity of the forces of electromagnetism and the so-called weak force involved in some kinds of radioactivity.

This hints at a larger underlying unity with a third force - the strong force that holds atomic nuclei together. Physicists want to probe further for this unity and perhaps even grope toward glimpses of a larger all-embracing unity that will include gravity, the last of the four basic material forces.

Dr. Lederman says he expects the $130 million Tevatron ''to begin to redress the balance in the cooperative rivalry between the US and Europe.''

With what has been found so far and with the prospect that other seminal discoveries are likely soon, British physicist Frank Close calls 1983 a new golden age of fundamental physics. Making this point recently in Nature magazine , he said one would have to go back half a century to the introduction of the first particle accelerator to find a comparable period.

To effectively follow up the recent discoveries, physicists need more powerful accelerators than have been available up to now. The basic natural forces and the basic nature of matter reveal new facets as they are probed at ever higher energies. It is a little like the new insights astronomers gain when they view the cosmos with increasingly powerful instruments to study finer and finer detail.

This is what Fermilab's Tevatron will contribute when it reaches full power with colliding beams in the next few years. The machine is able to reach higher energies because, following design studies initiated by former Fermilab director Robert R. Wilson, it now is equipped with superconducting magnets.

Cooled to the temperature of liquid helium (roughly -428 degrees F.), the coils of these magnets lose all resistance to electric current. So it takes little electric energy to run them. This means they can be much more powerful than the old magnets without generating large amounts of heat and consuming inordinate amounts of electricity.

In fact, the new design is called an energy saver because it actually holds down the Fermilab electric bill. With its budget cut a few years ago, Fermilab has been able to afford electricity only for half-time operation. Now it should be able to foot the bill for full operation.

The more powerful magnets allow the accelerator to handle more energetic particles. But this is still considered an interim step by US physicists.

To probe deeply into the new realm of basic physics, they would like at least one machine capable of reaching energies as high as 20 TeV. They call it the Desertron because it might be built in the desert, where land and other costs would be relatively cheap. Even then, it probably would cost $1 billion to $2 billion to build.

This is one of the options that has been under study in recent weeks by the US Department of Energy's High Energy Physics Advisory Panel (HEPAP), which has been meeting in Woods Hole, Mass.

HEPAP is expected to announce its recommendations for the future of US particle physics shortly. They are recommendations the Reagan administration is likely to take quite seriously. Indeed, presidential science adviser George A. Keyworth II has said that he leans toward the Desertron concept.

Meanwhile, Fermilab's success with its Tevatron has assured US physicists of a world-leading machine for the interim period of the mid-1980s.