Researchers confirm finding of top quark

March 01, 1995|By New York Times News Service

Scientists at the Fermi National Accelerator Laboratory in Illinois said yesterday that they had definitely found and measured the top quark, a fundamental but elusive building block of matter.

A spokesman for the laboratory said details of the landmark discovery would be disclosed in a scientific symposium scheduled for tomorrow in Batavia, Ill., when the mass and other important characteristics of the top quark would be announced.

The announcement reflects the intense rivalry between two competing groups of physicists at the 4-mile-circumference Fermilab accelerator ring. Each has been searching for the top quark with a different detector. More than 400 scientists and experts operate each of these detectors, known as the D0 ("D-Zero") and the CDF ("Collider Detector at Fermilab").

Although both coalitions intend to make announcements tomorrow, neither knows what the other will report, according to Dr. Paul D. Grannis, leader of the D0 detector group.

Last April, the other group, called the CDF Collaboration, electrified physics laboratories around the world with its announcement that it had probably found the top quark.

This ephemeral spark of matter, they reported, apparently had the astonishingly huge mass of about 174 billion electron-volts -- a mass heavier than an entire atom of gold. This may make the top quark the heaviest particle nature has ever created.

But last April the rival D0 team failed to produce similar evidence, and called the CDF claim "interesting but insignificant."

Despite the bickering, scientists speaking on condition of anonymity said yesterday that doubts have now virtually vanished that the top quark has at last been captured, and that its mass and cross section have been accurately measured.

It remains to be seen if the D0 group has merely confirmed its rival's earlier measurement or has found a different mass for the quark and thus relegated its rival's discovery to a false and premature claim.

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