Physics: Anti-Mirror on the Anti-Wall . . .

In the fantasies of science fiction, contraterrene, or CT, is something that strikes fear into the hearts of earthlings. CT is antimatter, which forms the substance of mysterious antiworlds where everything is the mirror image of its counterpart on earth. On some as yet undiscovered planet there might be antipeople who put freeze in their anti-cars, eat pasto for an anti-appetizer, take a dote to counteract antipoison or a biotic against anti-disease or a histamine for an anticold, who join the Defamation League and who put macassars on their anti-sofas. But antimatter is no joke. What is really fearful about it all is that contact of matter with its antimatter counterpart produces an explosive reaction that annihilates both.

Serious scientists have speculated a good deal about antimatter. They have already proved the existence of anti-particles—anti-protons, anti-neutrons, positrons (anti-electrons)—but are there also complex forms of antimatter? Many physicists have seriously doubted it. They did not have proof that particles of antimatter could be bound into anything as large as antiatoms in the same way that the nuclear force holds together earthly atoms.

33 Billion Volts. Last week a team of Columbia University researchers dispelled the doubts. In the Physical Review Letters, the Columbia scientists reported that they have produced the first complex nucleus of antimatter ever observed—the anti-deuteron. It is the antimatter counterpart to the nucleus of deuterium (heavy hydrogen), consists of an antiproton and antineutron bound by a strong nuclear force, and has a negative charge. Such an achievement, the Columbia researchers conclude, provides strong evidence to support theories about the existence of an antiworld of stars, planets, and possibly even antipeople.

To detect the existence of the anti-deuteron, Dr. Leon M. Lederman and his group worked with a device called a mass spectrometer at Brookhaven National Laboratory on Long Island. Using Brookhaven's 33 billion electron volt synchrotron, they bombarded a target of beryllium with a beam of high-energy protons. This resulted in a debris of. particles that sped through the 300-ft. magnetic field of the spectrometer, where they could be sorted and analyzed. When 16 giant, 20-ton magnets were set to pass positively charged particles, the apparatus made careful readings of the flight path, momentum and velocity of these particles. Computers showed where there was a mass peak of deuterons. Then, by reversing the field, the scientists ran the same tests to detect negatively charged particles. Since antiparticles behave the same way as their ordinary counterparts, the scientists concluded that they had found the anti-deuterons when the spectrometer showed a peak of activity where the deuteron had appeared earlier.