Top‐ology

MAY 01, 1997

The top quark, first seen just two years ago at the Tevatron, is uniquely heavy and short‐lived. But its virtual presence is felt in more familiar realms.

DOI: 10.1063/1.881890

Chris Quigg

The top quark os a most remarkable Particle even for a quark. A single “top,” as we will casually call it here, weighs 175 GeV, about as much as an atom of gold. But unlike the gold atom, which can be disassembled into 79 protons, 79 electrons and 118 neutrons, top seems to be indivisible. With an experimental resolution approaching $10^{−16} cm,$ we have not discerned any structure. Top’s predicted lifetime of about 0.4 yoctoseconds ${(0.4×10}^{−24} s)$ makes it by far the most ephemeral of the six varieties of quarks. The compensation for this exceedingly brief life is a measure of freedom: Top decays before it suffers the confining influence of the strong interactions. In spite of its fleeting existence, the top quark nonetheless helps shape the character of the everyday world.

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More about the Authors

Chris Quigg. Fermi National Accelerator Laboratory, Batavia, Illinois.