Telling the Tale of the Quarks
It is said that a student once asked Enrico Fermi about the name of a fundamental particle, and that Fermi responded, “Young man, if I could remember the names of these particles, I would have been a botanist.” At that time (the mid-1950s), only a dozen particles were known, but their taxonomy was already a tangled problem. Ten years later the list was approaching one hundred and getting longer as powerful new accelerators came on line and increasingly sensitive devices for particle detection were developed. The “botanists” among particle physicists were in despair.
The physicist who dominated the effort to bring order to this seemingly chaotic jungle of particles was Murray Gell-Mann, a man with a deep faith that beneath it all there were simple patterns dictated by symmetry principles. One of his tools was a mathematical device that quantum physicists had recognized since the early work of Bohr and Pauli: the quantum number. Some of the most mysterious of the elementary particles could be classified with a new quantum number appropriately called “strangeness.” In Gell-Mann's scheme, the strangeness quantum number became half of a more complicated system of particle groupings that led straight to the heart of the structural symmetries of protons and neutrons and their exotic relatives. Symmetry was the key because it could tell its story with no recourse to the still unknown details of the appropriate quantum dynamics. By proceeding with his eyes on symmetry theory, Gell-Mann gave birth to the now ubiquitous quark concept. That, in a nutshell, is one of the stories told in this chapter. Another is the story of Murray Gell-Mann himself.
He was born in 1929, when his family lived on Fourteenth Street in lower Manhattan. Arthur Gell-Mann, Murray's father, had gone to New York from Vienna as Isidore Gellmann. He soon adopted the name Arthur, and shortly after his marriage, added the distinctive hyphen to his last name. He was a distinguished-looking man with intellectual aspirations that never were realized. In Vienna, he had started philosophical and mathematical studies, but his par-